Service Learning Project
Amphibian Survey: Amphibian Abundance
within the University of Central Florida’s
Natural Lands
BSC 4861L
By Abner Fontanez, Alaina Kurtz, Andrew Lawrence, David Smith & Shelby
Moran
2
Abstract
Amphibians are considered to be an indicator species that thrive on both land and
water making them sensitive to many ecological disturbances, including deforestation
and pollution. We tested three different cypress domes that are known habitats for
amphibians in areas that have a variety of contact with human impacts. In each cypress
dome we set up aquatic traps, PVC pipe traps, and board traps that were checked four
times a week for amphibians. The results showed that Cypress dome B, the second
furthest dome from human activity, had the highest species diversity and richness. It is
worth noting that cypress dome A, the closest dome to human activity, had the highest
amount of amphibian individuals. We were unable to find a correlation between
proximity to human impacts and amphibian population diversity and richness.
3
Introduction
Over the past few decades there have been
rapid declines in global species biodiversity. This
declining trend has been witnessed within all types of
vertebrates and many are becoming threatened1,
endangered2, or extinct3. Among all of Earth’s
vertebrates, it is the amphibians (frogs, salamanders,
and caecilians) that have the greatest amount of
species on the verge of extinction (Hamer and
Figure1.UCFCypressDomelocated
nearStudentUnion.
McDonnell 2008). There are many factors that have been linked to the decline in
biodiversity5, and some of the most important causative factors include pollution6,
changes in land use, invasive species, which are organisms that are not native to an area
and are causing harm to the ecosystem (Ecology Dictionary), and overexploitation, the
over use of land for its resources (Ecology Dictionary) (Frias-Alvarez et al. 2010).
Amphibians are usually found in wetland habitats, such as the cypress dome
ecosystems9 in Central Florida (See Figure 1). Cypress domes are shallow swamps found
in the low elevation of terrains which can be found throughout Florida (Kurz and Wagner
1Threatened‐Any plant or animal species likely to become an "endangered" species within the foreseeable future
throughout all of a significant area of its range or natural habitat (Ecology Dictionary)
2Endangered-Probability of extinction is 20% within 20 years (Begon et al 203)
3Extinct-The complete disappearance of a species because of failure to adapt to environmental change (Ecology
Dictionary)
5Biodiversity‐Variety and variability of living organisms encompassing ecosystems in relation to community,
species, and genetic diversity (Begon et al 602)
6Pollution‐presence of a substance in the environment that because of its chemical composition or quantity prevents
the functioning of natural processes and produces undesirable environmental and health effects (Ecology Dictionary)
9Ecosystem‐The biological community together with which they interact including the surrounding physical
environment (Begon et al 499)
4
2012), making it a perfect habitat10 for amphibians, whose survival depends on the
availability of an appropriate aquatic habitat (Hamer and McDonnell 2008). Amphibians
need water to reproduce and for cutaneous respiration11, the main method of respiration12
in many amphibian species (Dodd 2010).
Amphibians are considered to be an “indicator species”. This means that they are
highly susceptible to changes in their habitats, which can lead to an increase or decrease
in the number of species found there. Indicator species signal the overall health of an
ecosystem. This is evident when amphibian habitats become polluted. An increase in
pollution is harmful to amphibians because they are both terrestrial and aquatic, meaning
they are more exposed to areas where a
pollutant can linger (Hamer and McDonnell
2008). Also, because they breathe using their
skin (see Figure 2), pollutants, which could be
picked up from the land or water, are more
likely to seriously harm them (Hamer and
Figure2.Amphibianrespiration
Source:"Frogs and Toads." areas, ecosystems with poor water or habitat quality are not likely to have healthy
McDonnell 2008). Aside from just polluted
amphibian populations.
10Habitat‐Location where an organism lives (Begon et al 31)
11Cutaneous Respiration_ Breathing through the skin; in some vertebrates the body surface has become highly
vascularized for gaseous exchange (Allaby 1999)
12Respiration- The oxidative process occurring within living cells by which the chemical energy of organic
molecules is released in a series of metabolic steps involving the consumption of oxygen and the liberation of carbon
dioxide and water (Ecology Dictionary)
5
The movement of amphibians from one habitat to another is a critical component
of amphibian dispersal (Hamer and McDonnell 2008). Research has shown that there is a
direct relationship between the amount of road traffic, which has increased in volume in
recent years, and the number of frogs found dead (Fahrig 1995). This is not only from
the cars driving on the roads, but it is also caused by road-related factors, such as
pollution, noise, and water runoff (Fahrig 1995). Worldwide there has been an increase
in both traffic volumes and amount of roads, which are contributing to declines in
amphibian populations (Fahrig 1995), particularly in populated areas, like UCF.
Urbanization is not the only factor causing many amphibians to become
threatened, endangered, or extinct. Increasing numbers of invasive species have also
contributed to the high number of extinct amphibians. Invasive species have also further
displaced amphibian life, thus changing the species biodiversity (Frias-Alvarez et al.
2010). One example of invasive species is the Cuban Tree-frog, Osteopilus
septentrionalis. These frogs were accidentally brought to Florida in the 1920s and they
are considered invasive because of their voracious appetites. Cuban treefrogs are known
to eat several different species of native frogs and their tadpoles compete with native
tadpoles for food (Johnson et al. 2007).
The main purpose of our study is to survey amphibian richness and biodiversity
within the University of Central Florida’s (UCF) main campus. Through our study, we
hope to find trends in amphibian species diversity and richness related to location. We
plan to do this by recording the amount and type of amphibian species in these areas and
comparing our data sets. We hypothesize that the wetland ecosystems that are furthest
from human activity will have the greatest amount of amphibian diversity and richness.
6
Increasing proximity to human activity also brings about many other factors, including an
increase in pollution, amount of roads, land change, and increased noise (Fahrig 1995).
Research has shown that the decrease in species populations is far more severe in
some amphibian families than others (Frias-Alvarez et al. 2010). Our data, once
collected, will be able to show us if any amphibian families known to be in Central
Florida seem to be on the decline, which we will be able to calculate based on the number
of times we catch them in relation to other amphibian families. This study should be able
to show if any invasive amphibian species are present, which will give light to possible
reasons for the current amphibian biodiversity.
All three of the amphibian habitats are cypress dome ecosystems located on the
UCF’s main campus, which is home to 58,698 students ("Facts About UCF"). The first
Cypress dome is located next to the campus’ Student Union, a very heavily populated
area. The second Cypress dome is located in the Arboretum, which is surrounded by two
of the campus’ busiest roads (Gemini Boulevard and Orion Boulevard). The third
Cypress dome, located the furthest from campus, is found off of Neptune Drive (See
figure 3). We believe that the area closest to human activity, the one within the main
campus and next to the student union, will have the least amphibian diversity and
richness while the furthest from campus will have the highest amphibian diversity and
richness.
7
Figure 3. A map of the locations of our three cypress domes on UCF campus.
8
Triple Bottom Line
Conducting this research and answering our hypothesis is important because vital
habitats for endangered or threatened amphibian species may be susceptible to impacts
that are caused directly by the university. UCF is growing at a rapid rate, this growth
could now, or in the future, impact considerations for places on campus to be used for
additional buildings, student housing, recreation areas, or road development. By
understanding which areas function as important ecosystems to endangered or threatened
amphibians, it is possible to prevent them from being altered or destroyed.
This research will help establish which areas around campus are the most suitable
habitat for species diversity in regards to amphibians and their proximity to humans. The
cypress domes we will be working in are protected and are representatives of nonprotected cypress dome ecosystems around UCF and what their amphibian populations
may be like, assuming they have comparable ecological factors. This could help protect
areas that are not already federally protected by implementing more laws to protect these
fragile environments, keeping them from being altered or polluted. Environmentally, this
is important because it can help keep sensitive areas rich in biodiversity, which could
help amphibians thrive.
Economically this research can provide an understanding of the important
amphibians and wildlife found on our campus, which could in turn help us receive grants
for further research of these areas and the species found within. This research should also
show the requirements needed by these ecosystems to remain or become healthy and
sustainable. In the future UCF may decide to create further jobs for the purpose of
9
maintaining the health of the arboretum, our research will be able to show them how to
help the amphibians in the area, saving them time and money.
This study will also increase the amount of knowledge we currently have on
wildlife found within the UCF main campus and allow us to have a better understanding
of the UCF protected lands. This will also help environmental studies and biology
students at UCF better understand wildlife and the importance of conservation. The
understanding of the diversity of amphibian species in these wetlands could end up
leading to an increase in the quality of these cypress dome habitats. This could raise the
aesthetic purposes of the arboretum and lead to an increased amount of hiking and
recreational uses of the natural lands by students and faculty of UCF and the surrounding
community.
10
Methods
In order to try and catch a variety of different amphibian species our study used
three different approaches for data collection. Each of the three designated survey areas
was set up with aquatic15 traps, PVC pipe traps, and plywood board traps. During the first
three weeks of the study we used all three types of traps, after which the aquatic traps
were removed but the other two types stayed in place for the remaining three weeks. All
the traps were set within the designated survey areas the afternoon before the primary
scheduled test date. Each of the designated survey areas was tested four times a week for
a total of six weeks (see Table 1).
Table 1. Weekly trapping schedule by location
Location
Area A
Area B
Area C
Tuesday
Test
Test
Test
Wednesday
Test
Test
Test
Thursday
Test
Test
Test
Friday
Test
Test
Test
While within the designated survey areas all researchers were required to wear
protective snake chaps and bite proof footwear. The afternoon before the scheduled test
date researchers placed three aquatic traps in each of the designated survey areas (see
object A in Figure 4). The aquatic traps were anchored in the middle of the cypress
domes where there is more standing water. Each trap had a minimum distance of ten feet
separating it from the other aquatic traps. The aquatic traps were placed partially
submerged in the water with roughly one to two inches of the trap exposed to the air, the
gap from the water’s surface to the top of the trap allowed captured specimens to breathe.
15Aquatic‐Growingorlivinginwater;frequentingwater(EcologyDictionary)
11
On the scheduled days each aquatic trap was removed from the water to check for
specimens. If a specimen was found researchers would collect water from the location
surrounding the trap in a collection bucket where the captured specimen was then
emptied for further examination and data collection. Researchers wore latex gloves
because amphibians have delicate skin that can be harmed by the oils on human hands.
While examining the species, researchers would determine the species type and measure
the organisms’ size in centimeters from snout to vent. After examination, all specimens
were released back into the location in which they were captured. These steps were
repeated four times a week for a total of three weeks. At the end of the third week all
traps were removed.
During the second and third trapping approaches, researchers used PVC pipes and
plywood traps for specimen collection. The afternoon before the scheduled test day
researchers set four PVC pipes near the base of trees within each of the designated survey
areas (see object B in Figure 4). Each PVC trap was set vertically in the ground. This
allowed for an opening at the top of the pipe to be exposed, while the bottom few inches
of the pipe remained in the ground. The PVC traps were used to collect arboreal16 frogs.
Researchers randomly placed two plywood boards on dry ground within each of
the survey areas (see object C in Figure 4). The plywood boards are used to attract
amphibians such as frogs, toads, and salamanders seeking a place of refuge during the
day. Both types of traps were checked during the afternoon of the scheduled test days.
When checking the PVC pipe traps, researchers would first remove the pipes from the
ground and then gently tap the sides of the PVC pipe to displace any collected specimens
16Arboreal‐inhabitingorfrequentingtrees(Merriam‐Webster)
12
into a collection bucket. The collected frogs and/or specimens were further examined to
determine their species type and size for data collection. In order to check the plywood
traps, researchers would slowly lift up the board, examine, and record any specimens
found beneath them.
Figure 4. A layout of the traps within the cypress domes.
During the course of this study, researchers were testing for richness and
biodiversity within each of the designated survey areas. The following data was recorded
during each of the three approaches: location, date, temperature, humidity (%), wind
speed, trap type, amphibian type, species name, size (cm), photo #, invasive, and any
13
other observations made by the researchers (see Figure 5). Each of the three designated
survey areas was given a folder with a corresponding color-coded title where recorded
data sheets were placed. After the recordings were complete, researchers transferred data
from the three folders to an Excel document. The data was then analyzed in excel with
focus on richness and biodiversity. This correlation of data was used to help answer our
purposed hypothesis.
Once the data had been inputted into excel the species richness was determined by
looking at the number of species found in each dome. The proportion of species for each
dome was calculated by taking the species richness and dividing it by the overall number
of amphibians caught in that dome. Next, diversity index was calculated by using the
Shannon-Wiener diversity equation; which is used to find the biodiversity of a habitat
(Figure 6).
Figure 6. Shannon-Wiener equation with pi representing the proportion of the species
and ln is the natural logarithm.
Changes
Once we began to conduct our project we decided to change various components
of our original methods. One approach that we agreed to dispose of was the use of an
audio recorder to identify amphibians by their call. This would have been a time
14
consuming process that would likely have resulted in no data collection. Aquatic trap use
was also extended by an extra week than previously planned. Once we began our
research we found that these traps were the most effective in capturing amphibian species
and through continuation we would be likely to obtain a higher number of species to
survey. The number of PVC pipe traps used in each dome was changed as well from
three to four in order to increase our chance of amphibian capture. Our weekly trapping
schedule based on location was also modified to four times a week in each dome as
opposed to four times a week alternating between the different domes, each dome being
visited twice a week. This was due to our belief that we would collect more data if we
checked each cypress dome more often.
Materials
Reptiles and Amphibians

Camera
Peterson Field Guides

Notebooks (3)

Florida Frog Species Calls CD

Aquatic Amphibian Trap (9)

4x5’ Plywood Sheets (6)

Latex Gloves

PVC amphibian Trap (9)

Plastic collection bucket

Excel

Caliper

ArcGIS

Flash Light

Snake Chaps (5)

Rubber Boots (5)

Audio Recorder

Thermometer

Nets (2)

Figure 5. A copy of the data sheet used to collect research
15
16
Results
Overall our data does not support our hypothesis that wetland ecosystems furthest
from human activity will have the greatest amount of amphibian biodiversity and
richness. Calculations of species richness shows that cypress dome A (student union) and
C (east parcel) where both found to contain 4 different species of amphibian, while
cypress dome B (North Orion) contained 6 different species of amphibian (Table. 2).
Though we expected for the east parcel to have the most and the union to have the least,
these two were actually tied and behind the North Orion parcel. Amphibian abundance
was highest in the Union Parcel with 26 amphibians, closely followed by North Orion
parcel, which had 23. The East Parcel only had six.
Calculations of amphibian biodiversity again showed cypress dome B as the area
with the highest biodiversity. This was followed by cypress dome C and then cypress
dome A (Figure. 7). Cuban treefrogs were found in B (North Orion) making up 9% of
the amphibian population (Figure 8). And we found Cuban treefrogs in C (East Parcel)
that made up 40% of the amphibian population (Figure 9). No Cuban treefrogs were
found in A. No other invasive species were found in any of the cypress domes.
17
Table 2. Species Richness of 3 different cypress domes showing species richness and
Total abundance.
A (Student Union)
Species
Green Tree Frog
Southern Toad
Abundance
Results
3 Species Richness
4
15 Total Abundance
26
Squirrel Tree Frog
Southern Leopard
Frog
4
B (North Orion)
Two Toed
Amphuma
2 Species Richness
6
Green Tree Frog
2 Total Abundance
23
Squirrel Tree Frog
Eastern
Narrowmouth
Toad
7
Cuban Tree Frog
Southern Leopard
Frog
C (East Parcel)
4
8
2
2
Cuban Tree Frog
2 Species Richness
4
Barking Tree Frog
Pine Woods Tree
Frog
Southern Leopard
Frog
1 Total Abundance
5
1
1
18
1.8
1.6
1.4
1.578882006
C East Parcel
B North Orion
A Student Union
Biodiversity Index
1.2
1
1.33217904
1.14244482
0.8
0.6
0.4
0.2
0
Diversity Index A
Diversity Index B
Diversity Index C
Parcel Surveyed
Figure7.BiodiversityofeachParcelsurveyedcontainingdiversityindexand
standarddeviation.
Figure8.AbundanceofeachspeciesofamphibianwithincypressdomeB(North
Orion).
Figure9.AbundanceofeachspeciesofamphibianwithincypressdomeC(East
Parcel).
19
20
Discussion
Though the diversity and richness of the amphibian populations did vary greatly
in each different cypress dome, it seems that they did not correlate with their proximity to
human impact. The healthiest ecosystem appears to be cypress dome B followed closely
by cypress dome A. It seems the least healthy was cypress dome C. Cypress dome B was
likely the healthiest because it was not as heavily effected by human impacts as cypress
dome A. A was located right next to a building and directly under two high trafficked
wooden walkways, because of this A had a higher amount of pollution and liter. Also, B
was connected to the UCF arboretum, which meant wildlife could come and go from the
cypress dome safely, which could have increased the biodiversity. Buildings and roads
locked in parcel A preventing any access to other undisturbed ecosystems.
Though cypress dome A had the highest amount of amphibians caught, it also had
the lowest species diversity. This was because the southern toad represented 57% of the
amphibians caught. Southern toads are not known to outcompete or harm other
amphibian species, so this high percentage should not be a concern (Guzy 2010).
It may have seemed like cypress dome C was the least disturbed and likely the
healthiest, the data showed otherwise. We have debated a few different possibilities for
why cypress dome C had an amphibian abundance that was three times less than in
cypress dome A and we have concluded that either we made errors while collecting our
research or there were unforeseen environmental factors in this cypress dome harming the
amphibian populations.
A possible collecting error we could have made was not fully appreciating the
size of this cypress dome compared to the other two. Cypress dome C was our largest
21
cypress dome, which meant that the amphibians could be more spread out in this area as
compared to the others, as they had a larger area to forage, hunt, and search for mates.
We are curious as to if it would have been more beneficial to calculate the approximate
size of each cypress dome and determine the number of traps to lay out based off of that.
This dome had the same amount of traps as the other two, which may have decreased our
chance of finding as many amphibians.
Another possible explanation for the low richness of the cypress dome could be
unforeseen environmental factors. The water level in this dome was constantly above
two feet as apposed to the other two, where the water levels were much lower. This could
have created a better-suited habitat for carnivorous insect species that prey on amphibian
eggs and tadpoles, decreasing the amphibian populations (Morin et al 1988). Another
factor could be the amount of invasive amphibian species in this area. Of the amphibians
we did manage to catch in this dome, 40% were Cuban treefrogs, an invasive species that
is known to compete with and predate on other amphibian species.
While conducting our research we were met with a few barriers that we had to
overcome. One barrier was the initial inability to catch any amphibians; this problem
was resolved after realizing that amphibians were not going to be showing up every
single time we went out. We increased our amount of traps and moved some of them
around and slowly began finding results. We also began using nets to catch amphibians
as we walked around checking our traps, which ended up yielding 47% of our total
amphibian catches. 22
Though a correlation between proximity to human impact and the calculated
diversity and richness was not found, the overall health of these ecosystems is known.
We suggest further research into the amphibian populations in these cypress domes.
Future studies should be prepared to set aside more time than six weeks and set out a
higher number of traps in each cypress dome. Researchers should try to survey through a
wide variety of weather conditions and continue using a wide variety of trap types.
Future researchers should set more time into discovering why cypress dome C had such a
poor amphibian population. They should look at possible pollution levels and other
species that may be competing with the native amphibian species.
Though many people do not understand the importance of amphibians, our natural
lands would not be as enticing without them. If our amphibian populations went into a
sharp decline, mosquito and insect populations would increase while larger wildlife
populations would decrease. This would take away from the aesthetic purposes of our
natural lands, leading to a possible decrease and tourism along with the decline that
would happen in biodiversity.
Amphibians are considered indicator species, which means any significant change
in their population numbers would imply that changes are happening within their
ecosystems. By conducting amphibian surveys on a relatively regular basis, ecologists
would be able to find out if there may be a problem in an ecosystem, such as pollution or
invasive species, before it harms the environment and the wildlife too much.
23
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Water Lettuce and Apple Snails’ Ability
for Bioremediation of Copper
Sara Channell, Diego Santos, Bri Tampa, Jennifer Walls, Jessy Wayles
ABSTRACT
Central Florida’s waters are in critical need of restoration. Recognizing which plants and
animals that help in restoring our waters will provide a realistic and cost efficient solution. Our
research focused on the capacity of Water Lettuce (Pistia stratiotes) and Apple Snails (Pomacea
insularum), which are both classified as invasive, to improve water quality in lake systems
contaminated with Copper. To perform this project, we created an environment suitable for the
animals involving a recirculating system. Overall, the system contained 8 tubs; a control, plants,
snails, and plants and snails. Out of the six weeks of expected research only four weeks were
conducted due to the initial spraying of Cu and lack of health of the snails and water lettuce.
After reestablishing the tubs we were able to conduct four weeks of data. We assessed the
efficiency of bioremediation by testing the levels of Cu weekly within each of the eight tubs. The
water from each tub was tested for the concentration of Cu and was read using an YSI 9,500
photometer. The results showed that P. insularum was most efficient at bioremediation of copper
than P. stratiotes and P. Insularum together and together. Further research is required to
determine if the classified invasive species P. stratiotes and P. insularum are sufficient at the
removal of Cu in lake systems.
INTRODUCTION
Florida’s water quality is becoming
an increasing issue. Nitrate rich pesticides
have been intentionally introduced into
Florida’s freshwater ecosystem. The
increasing use of these pesticides are
threatening the balance and causing
environmental pollution. The adding of
nutrients, such as copper, nitrogen and
phosphorus, is one of the most common
pollutants affecting the Florida’s freshwater.
It accounts for more than 50% of reported
water quality impairment (Huang, 2009). A
large portion of these waters and the
surrounding area are used for agriculture
treated with fertilizers and pesticides,
including Cu (Hoang, 2009). Over 45% of
Florida's lakes are considered impaired from
pollutants and stressors, such as an over
abundance of nutrients, metals, excess algae
growth, and pesticides (Quality of
America’s Lakes, 2000). The toxicity of all
fresh water bodies are interconnected, the
runoff from fertilizer laced lawns eventually
trickles down and pollutes the Floridan
aquifer. This causes excessive algae growth
around the mouth of many springs which in
turn slows down the flow and leads to even
more algae growth. Spraying toxic
chemicals to treat unwanted aquatic plants
such as hydrilla is common practice in
Florida waterways. It is uncertain what kind
of affect the chemicals are having on the
native wildlife in the spring runs and rivers
due to lack of research. The vibrant green of
algae is the environment’s response to
nutrient runoff which can be made worse by
heavy rainfall ("Florida waters alive", 2013).
Invasive species are defined as a
nonnative species that out competes a native
species for resources (USDA, 2006). Water
lettuce and island apple snails are two non-
native species that plague central Florida’s
river systems. Island apple snails are known
to grow larger than the native Florida apple
snail and are thought to be a source of
frustration to the threatened snail kite
(Kitchens, 2010). Water lettuce is known to
form dense mats that shut out sunlight to the
submerged plants below, as well as cause
problems for boaters and swimmers who are
used to a clear path in a certain part of their
creek (Ramey, 2001). The fact of the matter
is that many invasive species are here to
stay, and while chemical-laced means of
disposal are culling the population in certain
areas many of these species are producing
quickly and hindering the growth of native
species.
There are many invasive species of
flora and fauna that can be used to our
advantage instead of being destroyed by
harmful chemicals. If an invasive species
cannot be contained, and is thriving in our
ecosystems despite extensive measures to
get rid of it we should begin planning ways
to use them to our advantage, because like
the plants and animals that share an
ecosystem with invasive aquatic species, we
need to learn to adapt and grow.
The apple snail is one of the many
invasive species in Florida. Apple snails are
large freshwater gastropods that are native to
tropical and subtropical areas around the
world (Barker, 2002). They are commonly
known as mystery snails, or golden mystery
snails in the pet trade (Barker, 2002). Many
species of apple snail inhibit slow moving
rivers and lakes, and are perfectly at home in
marshes and ditches (Barker, 2002). All
apple snails have both lungs and gills which
makes it possible for them to live in a dried
lake bed for 9 months to a year (Barker,
2002). There are five species of apple snail
in Florida, and only one of them is native.
The most prominent species of apple snail in
Florida is the Island Apple Snail, Pomacea
insularum, originally thought to be released
into the wild by aquarium hobbyists who
became aggravated by the snail’s ability to
uproot and destroy a planted tank in a very
short amount of time.
While P. insularum is considered to
be an invasive species the reasoning is
vague or inaccurate. Many cite the plight of
the threatened Florida Snail Kite as a reason
to rid the state of these creatures. The snail
kite feasts almost exclusively on apple snails
and studies have shown that juvenile snail
kites have trouble opening the larger P.
insularum, and therefore expend more
energy than acquired by eating the snail
(Kitchens, 2010). However limpkins also eat
the apple snails and they have no problem
opening the larger snails. By having P.
insularum in the same population there is an
abundance of food available for both species
of birds.
P.
insularum
are
voracious
herbivores and are known to wreak havoc on
aquatic plants and habitats. While they do
devour native aquatic plants they are also
extremely partial to hydrilla (Hydrilla
verticillata), a highly invasive aquatic plant
that is choking our spring runs and pushing
out native species of plants (Mitchel, 2004).
By culling invasive plant populations, and
being reproductively successful so more
snails are available to be a primary food
source for native birds, one could argue that
P. insularum, while nonnative, are not as
invasive as once considered and should not
be actively destroyed with chemicals that
could potentially harm the species around
them.
Water lettuce (Pistia stratiotes) is a
floating aquatic plant with large soft leaves
that form a rosette and roots that hang
submersed beneath the floating leaves. It is
considered a weed in Florida because it can
form large thick mats that clog water ways
(Ramey, 2001) and also has the potential to
reduce biodiversity in a water way by
blocking gas exchange at the surface, which
in turn reduces oxygen and kills fish
(Ramey, 2001). The large mats of water
lettuce also block light which can kill
submerged plants, and can potentially crush
the plant communities. Water lettuce, while
it has its faults, can be used to clean up a
river system as water lettuce is known for its
water purifying ability (Reddy et al., 1982).
It can outcompete with algae for nutrients in
the water and thereby prevents algae blooms
(Pirie, 1960). Compared to native plants,
this invasive species shows significantly
higher nutrient removal efficiency with their
high nutrient uptake. They have a large
capacity, a fast growth rate, and a big
biomass production (Reddy and Sutton
1983). Water lettuce can double their
number and size in one to two weeks (Lu
and He, 2010). The success of water
treatments using aquatic plants depends on
the growth rate of the specific plants, and
how they utilize solar energy as well as the
available nutrients (Reddy and DeBusk,
1984).
While these plants are considered
highly invasive, they can be very useful to
society. Pirie studied water lettuce, and
another invasive water purifier called water
hyacinth and deemed that both species could
be used as fertilizer, livestock feed, or even
human food (Pirie,1960) if we put the time
and effort into harvesting the plants instead
of attempting to destroy them with
chemicals.
Copper is an element that can be
found for all biota, however anthropogenic
sources for copper can cause water
pollution, and toxicity to aquatic organisms
(Gendy, 2009) Copper sulfate is example of
an herbicide that is commonly used to rid
lakes and ponds of an overgrowth of algae
called “algae blooms.” Specifically within
the Central Florida area, Cutrine, an
anthropogenic copper source with 9% of the
element as an active ingredient is dispersed
throughout fresh water bodies. It is used to
control many species of algae as well as
hydrilla, which as we discussed earlier is
highly invasive in the central Florida area.
The following can be found on the Cutrine
label: that water treated with this pesticide is
safe for swimming, drinking, animals, and
watering lawns (MSDS No. D7120, 2007).
The label sounds relatively safe; however
Cutrine can affect the entire ecosystem as
well
as
non-targeted
organisms
(Deoliveirafilho, 2009). Over the past two
decades, copper from anthropogenic sources
have caused toxicity to aquatic organisms
and has contaminated freshwater ecosystems
(Deoliveirafilho, 2009). When exposed to
heavy metals, such as copper sulfate, aquatic
invertebrates have developed ways to
regulate internal copper concentrations and
essentially build up copper in their systems
(Hoang, 2008). Studies have determined that
the apple snail can accumulate copper from
a variety of sources in its environment such
as food, soil, and water (Hoang, 2008),
however it has been shown that copper
transfer through the food chain was the most
important route of uptake as compared to
water or soil exposure (Hoang, 2008). This
raises the question about apple snail
predators such as the snail kite and limpkins
and how much of the pesticide they are
being exposed to when they eat the apple
snails (Hoang, 2008). This pesticide has
been developed to poison aquatic plants
therefore
Cutrine
has
devastating
consequences for water lettuce. The copper
in Cutrine triggers oxidative stress in rooted
aquatic plants and equally harms floating
and immersed plants (Upadhyay, 2009)
short term copper exposure has been studied
to have an effect on the biochemistry and
physiology of aquatic plants (Upadhyay,
2009). Exposures and effects from
anthropogenic copper sources (Cutrine) can
be studied in living organisms known as
biomarkers (Gendy,2009 ).
Sustainability is often defined by
three pillars: environment, economy, and
equity. From an ecological point of view,
the relationship between aquatic organisms
and their ecosystem is being affected by the
application of chemicals into the pond
systems to treat nuisance plants such as
invasive species and algae blooms. This
addition of chemicals harms the system by
messing with the ph and chemical levels.
The biodiversity of organisms will not
tolerate heavy metals; it will lead to the
eventual demise of keystone species from
heavy metal build up due to preying on
chemical-laden invertebrates and fish. When
a keystone species is lost, it affects the hub
and therefore the metapopulations. By
focusing on restoration of a hub, more
species can be positively influenced and the
ecosystem’s health can be improved.
Environmental pollutants and toxins
come at a huge economic cost along with a
cost to the environment. According to the
U.S. Geological survey, “Cleaning up
existing environmental contamination in the
United States could cost as much as $1
trillion dollars” (U.S. Geological Survey).
Bioremediation is shown in Figure 1 and is
defined as, “the use of either naturally
occurring or deliberately introduced
microorganisms or other forms of life to
consume and break down environmental
pollutants, in order to clean up a polluted
site” (Baker and Herson ,1994).
Figure 1 Bioremediation of copper with water lettuce and
apple snails
It works as a cost effective solution,
because it has the ability to treat toxins in
place, reduce environmental stress, and
harness natural processes (U.S. Geological
Survey). Bioremediation also addresses
restoration instead of displacement and
therefore further helps the environment.
Invasive species are also a great
economic cost to the government. Apple
snails and water lettuce are both invasive
species and understanding these species that
are already present at polluted sites could
address the aspect of bioremedation by
harnessing natural processes and treating
toxins in place. If invasive species could be
better understood, they could possibly be
used as helpful measures to clean the pond
systems instead of adding more chemicals
and economic burden to the ponds. Florida’s
water systems are a major source of tourism.
If the water ways cannot be cleaned up, it
will adversely affect the communities
around them.
Clean water has an increased
economic impact for the state of Florida,
especially when it comes to tourism. Many
people travel here to experience the white
sand beaches, or hang out with friends on
the lawns beside cool springs. Florida’s
ecosystems attract more than $67 billion in
tourism and recreational spending each year
(Guest, 2012). However, algae outbreaks
can have devastating impacts on waterdedicated tourist destinations (Guest, 2012).
Even one harmful algae outbreak may cause
visitors to avoid a region, or even the state
of Florida as a whole, which could spell
disaster for cities, and towns that rely on
eco-tourism to survive (Guest, 2012).
HYPOTHESIS
Based on previous research, it was
predicted that a large biomass would provide
a greater bioaccumulation and therefore a
greater bioremediation. This study presented
the hypothesis that the combintation of P.
stratiotes
and
P.
insularum
will
bioremediate the copper treated water more
efficiently than P. stratiotes or P. insularum
alone.
METHODS AND MATERIALS
The experimental design changed in
the first two weeks of data collection due to
trial and error. The experiment was
originally designed to use PVC pipes with
holes drilled into them that would harbor the
water lettuce and collect water pumped from
the tubs so it ran through the PVC pipes,
over the roots of the plants, and trickle back
into the tub to be reused. It was observed
that the water lettuce was not able to thrive
in this system so the experiment was
redesigned without the PVC pipes and the
plants were placed directly in the water in
the tubs. Refer to Figure 2.
Figure 2 Top original set up with the PVC pipes; Bottom
final design with water lettuce floating
The experiment was performed in a
garage to avoid predation of the plants and
snails. From 8 am to 8 pm the garage door
was opened for sunlight exposure. 8 tubs
were filled with 10 gallons of water obtained
from pond nine on UCF campus, refer to
Figure 3.
temperature. These tests were simple tests
that involved the sampling of the water in a
test tube, inserting a tablet for the
appropriate test and waiting five minutes to
compare the results to a provided color
scale. Copper was tested using a 9500 YSI
Photometer. Once a week for 4 weeks the
water was tested using the urban water
testing kit and photometer.
Figure 3 UCF Pond map, highlighting pond 9 in red
A water pump that circulated the water was
installed in the tubs. Each tub was exposed
to the same amount of sunlight and external
environment. Several various sized snails
were collected from treated ponds on
campus and a dozen various sized water
lettuces were collected from the Wekiva
River. Snails and water lettuce were divided
so that the biomasses were equal. The tanks
with the combination of apple snails and
water lettuce contained smaller apple snails
than the tank that housed apple snails alone.
Two tubs contained only snails, two tubs
contained only water lettuces, two tubs
contained both snails and water lettuces, and
the two control tubs contained only pond
water. Submerged plants that were found in
the treated ponds were used to feed the
snails.
The water was tested before the
experiment using an urban water testing kit
for bacteria, chlorine, dissolved oxygen,
hardness, iron, nitrate, pH, phosphate, and
RESULTS
Table 1 displays the average amount
of total copper in parts per million (ppm) per
manipulation across four weeks. These
results are interpreted in Figure 4. Figure 4
shows the trends of total copper in ppm over
a four week time period. In the four different
trials the amount of copper went down each
week and got the lowest in the tank with
only P. insularum and remained the highest
in the control. The initial drop is thought to
be due to being tested from the tanks for the
first time. The second point is a week after
the tanks had been set up and the systems
started working on the small scale of the
tanks rather than the whole lake. Figure 5
displays the standard error and that there is
no significant difference between some of
the results. The tanks that contained the
apple snails showed a significant difference
compared to those that did not, but not
between each other. The other tests
performed were found to show no
significant results. It is also important to
note the condition of the P. stratiotes over
the four weeks; the water lettuce was
browning, wilting and showing signs of
dying. In addition to the water lettuce dying
some of the apple snails showed decreasing
health.
Table 1 The averaged results of the 9500 YSI copper test
Total Copper (ppm)
Week 1 Week 2 Week 3 Week 4
control
0.22
0.06
0.09
0.14
P. stratiotes (water lettuce)
0.22
0.05
0.10
0.10
P. insularum (apple snail)
0.22
0.02
0.01
0.01
water lettuce and apple snail 0.22
0.03
0.02
0.02
Figure 4 Trends of the loss in copper over four weeks
Figure 5 Loss of copper over four weeks with standard error bars
DISCUSSION
Water lettuce and apple snails did
affect the concentration of copper in the
tanks. The apple snails were more efficient
than the water lettuce at the removal of
copper and together they were less efficient
than apple snails alone. These results do not
provide support for the hypothesis. The
combination of water lettuce and apple
snails together was not the most efficient at
the removal of copper.
There may be several reasons why
the combination of apple snails and water
lettuce was not most efficient at the removal
of copper. One aspect of influence could be
the YSI 9500 machine used to test the
solution of copper displayed inconsistent
readings. The machines inconsistency
resulted from the amount of copper settled
in the test tube when the reading was done.
The method used in order to receive the
most reliable copper reading was shaking
the bottle so the copper was evenly
distributed throughout the test tube and then
taking a reading after 2 seconds. There is
also the inherent variability when multiple
lab partners measure the same thing.
Another reason could amount to the
poor health quality of the water lettuce and
apple snails that possibly contributed to their
potential to bioremediate. The poor health of
the water lettuce could be from the lag time
between their original habitat and the tanks.
The experiment was 6 weeks in total and
after the first 2 weeks the experiment had to
be restarted because the apple snails and
water lettuce died after being sprayed with
Cutrine. During this time period of 2 weeks,
there was leftover water lettuce from the
initial collection from Wekiva Island that
then replaced the water lettuce that was
impaired from the copper spray. The water
lettuce displayed signs of wilting,
discoloration, and was subject to predation.
induced oxidative stress in water lettuce
characterized by the initiation of lipid
peroxidation that inhibited growth and
disintegration of major antioxidant systems”
(Upadhyay 623). The oxidative stress could
hinder the capacity for water lettuce to
bioremediate copper.
The poor health of the apple snails is
attributed to where they were living previous
to being collected. The apple snails were
obtained from the UCF lake that was subject
to copper sprays. There was a significant
amount of dead snails present when the only
visibly remaining apple snails were
collected for research. This is also why the
tanks were not sprayed with copper after
they were reestablished because the water
collected from lake already had copper
present. Studies concluded that the
bioaccumulation of copper in apple snails
was most significant in dietary uptake
(Hoang 605) or soil (The Pomacea Project).
It is possible that the diet of the apple snails
also contained copper because their food
source was also collected from the lake that
was sprayed and there was no significant
soil accumulation present at the bottom of
the tanks.
Another consideration for the
potential to bioremediate is the amount of
carbon dioxide released by each organism.
According to a study by the U.S. Geological
Survey
studies,
“had
shown
that
microorganisms naturally present in the soils
were actively consuming fuel-derived toxic
compounds and transforming them into
harmless carbon dioxide” (U.S. Geological
Survey). Plants are only able to release
carbon dioxide at night for a relatively short
period of time during respiration when
photosynthesis is not taking place and the
apple snails release carbon dioxide
throughout the day while breathing. Millar
explains that, “Mitochondrial respiration in
plants provides energy for biosynthesis, and
its balance with photosynthesis determines
the rate of plant biomass accumulation”
(Millar 2011). The potential for species to
bioremediate could be influenced by their
ability to bioaccumulate in correlation to
their biomass. The difference in size of the
apple snails is also worth noting, as the
tanks that only housed apple snails
contained larger snails than the tanks that
held both apple snails and water lettuce.
This could explain why the tank that
contained both the water lettuce and apple
snails was not as efficient as the tank that
contained the apple snails alone.
Consideration of the locations where
the apple snails and water lettuce were
collected also could have influenced the
potential to bioremediate copper. The reason
the apple snails were more efficient than
water lettuce could also be because they had
more experience with copper. The water
lettuce was being controlled at Wekiva
Island with salt sprays and the apple snails
were being controlled with copper sprays.
Since the apple snails were subject to the
sprays it is possible that they become more
efficient at the bioremediation of copper.
According to Upadhyay, when water lettuce
is exposed to copper it has a, “a remarkable
effect on the biochemistry and physiology,
Further research is required to
determine if water lettuce and apple snails
are sufficient at the removal of copper. Both
apple snails and water lettuce are classified
as invasive and further research could
indicate if there is a relationship between
polluted water that allows for a species to
flourish leading to its invasive classification.
Copper is a dangerous additive to an
ecosystem and more research should be
done before widespread use is continued.
The harmful effects of copper in the
environment were seen the first two weeks
of research when the apple snails and water
lettuce died or significantly suffered in
health immediately after the initial spray of
copper. Further research could indicate what
species are able to bioremediate pollutants
most efficiently in order to improve
ecosystem health.
Agriculture: National Agriculture Library
[Internet]. [2007 Sept 1; cited 2012 Sept 25];
Available from:
http://www.invasivespeciesinfo.gov/
(2013). Florida Waters Alive with Toxic
Algae, Toxic Politics. [Internet]. [cited 2013
Sept 25]; Available from: http://ensnewswire.com/2013/08/21/florida-watersalive-with-toxic-algae-toxic-politics/
(2013). UF - IFAS Center for Aquatic and
Invasive Plants [Internet]. [cited Sept 24];
Available from: http://plants.ifas.ufl.edu/
ACKNOWLEDGEMENTS
Our sincerest gratitude to our
professors, Alaina Bernard and Jennifer
Elliot, for their continual guidance,
knowledge, and motivation throughout the
project. Thank you to the financial
contributions from UCF and all who have
made this project possible.
Anthony R., Douglas J., (Eds) (1997). The
Geology of Florida. University Press of
Florida. pp. 82–88, 238. ISBN 0-8130-14964.
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ml
Biodiversity of Indicator Species Present in Florida Friendly Ponds
Gabrielle Cerep, Sydney Jimenez, Rhett Stanberry, Angelica Tagliarini, Marisa
Zimmerman
BSC 4861
December 9, 2013
Abstract
Sustainable development is an important goal for society, and is discussed by
ecologists all over the world. This study tested the effects on pond biodiversity by a
theoretically sustainable practice called “Florida Friendly Landscaping,” which
implements a number of specifically environmentally beneficial practices to the
landscaping and creation of and surrounding retention ponds in Florida. To
determine if Florida Friendly retention ponds were successful, we compared the
biodiversity of three retention ponds that met Florida Friendly criteria, and three
ponds that did not meet the criteria, on the University of Central Florida campus.
Ponds were surveyed for indicator species by means of observation for ten minutes
twice per day, three times per week, for six weeks. Two minnow traps were also set
in each pond, and checked before every observational surveying period. Biodiversity
was then quantified using observed species and Simpson’s Index equation. In this
study, Florida Friendly ponds were found to have a higher count of indicator
species, but a lower measure of biodiversity – thus making the study insufficient for
determining whether or not Florida Friendly landscaping is beneficial for Florida
pond ecosystems. With these results, other studies may be conducted to determine
if abundance of indicator species or observable biodiversity is more important when
assessing the health of an ecosystem. Florida Friendly may still prove to be
beneficial because of the relatively large abundance of individual organisms, but if
obtaining higher biodiversity is the goal, creating Florida Friendly pond habitat may
be counterproductive.
Introduction
Urbanization contributes to many drastic changes in the natural world, which may
affect environmental health. The development of urban areas causes habitat loss and
fragmentation, increased levels of pollution entering the atmosphere and waterways, and
a decrease in the number of plant and animal species that are able to survive (Hamer and
McDonnell, 2008). With urbanization increasing with no end in sight, these
anthropogenic–caused problems will only worsen. One way to assess the negative effects
of development is to test the quality of a body of water. Pollutants such as chemicals,
fertilizers, gasoline, and garbage can all end up in a city’s waterways. These pollutants
destroy ecosystems, and eradicate plant and animal life.
As cities and urban areas continue to grow, it becomes more important to
determine the effects urbanization is having on the environment. Sets of guidelines were
developed by the United States Fish and Wildlife Service in order to monitor habitat for
selected species of wildlife (Landres, Verner and Thomas, 1988). These “evaluation
species,” were selected based on ecological criteria, such as “sensitivity to environmental
factors” (Landres, Verner, and Thomas, 1988, p. 318). This method was developed into
the use of indicator species in order to assess a wide variety of environmental health
issues.
One major determinant of ecosystem health is the presence of indicator species, or
animals that “are sensitive to environmental contaminants or habitat attributes of
concern” (Landres, Verner and Thomas, 1988) which makes them excellent candidates
for assessing the overall health of an ecosystem. For pond ecosystems in particular, these
species can range from herpetofauna to fish because of their sensitivity to the elements
around them. This sensitivity is due to their permeable skin that can absorb toxins and
other pollutants from their constant interaction with aquatic ecosystems. Because of this,
indicator species are successful in assessing air and water quality (Landres, Verner &
Thomas, 1988). Frog species in particular are important indicator species because of their
ability to go between water and land habitats, making them an important indicator to the
health of a pond ecosystem. The use of indicators to determine health is effective because
if the most sensitive animals are able to thrive, then other plants and animals should also
be able to do fine in these ecosystems.
In Barabasi and Bonabeau’s article Scale-Free Networks (2003), the concept of a
hub is presented; meaning the center of a network has many more connections to other
components. Thinking in these terms, each pond is considered a hub, and wildlife can
travel through the network of different ponds. Because of this, ponds were chosen for this
project because they are partially closed hubs, and the distance between ponds makes it
difficult for smaller fauna, or amphibians, to migrate between ponds. Many more factors
affect frogs than most other species due to their prevalence in the food chain. Frogs can
also affect many more species as well. This is why the abundance of indicator species
was determined to be the most effective way of measuring the health of the pond
ecosystems and how to better manage them sustainably. In order to create and maintain
sustainable ecosystems, we have to at least have a basic understanding of the
interconnections between indicator species and their functions related to other ecosystem
functions, processes, and how they are all interdependent upon each other (Bengtsson,
1998). Knowing the connections between all ecosystem processes can lead to sustainable
ecosystem management because of the larger implications of these connections, and their
impacts on our own lives and those of the organisms living in these ecosystems.
Amphibian populations have been declining worldwide, which is causing major
concern for environmentalists and scientists (Nystro, et al 2007). Amphibian decline
causes concern that other species of both plants and animals may decline as well, due to
the water and air quality conditions that are causing amphibian decline (Nystro et al
2007). Worldwide amphibian decline has caused many advocates of the environment to
want to test air and water quality to determine the sources of pollution. Urban areas are
common test sites due to the heavy anthropogenic influences these areas have (Beebee
and Griffiths, 2005). In Florida, urban freshwater systems are commonly tested.
Ultimately, this study is using indicator species to quantify biodiversity. The more
indicator species and individuals present, the more individuals from other species may be
supported by that ecosystem. For the purposes of this experiment, species biodiversity
may be defined simply as “the variety and abundance of different types of organisms
which inhabit an area” (Jenson et al., 1990). Biodiversity is arguably the determining
factor for ecosystem health. This is because the more species present, the more niches are
filled - therefore the more productive the ecosystem is. A niche is a role an organism
plays in its environment (Jenson et al., 1990). It stands to reason an ecosystem is likely to
collapse if certain roles are not filled. A high measure of biodiversity ensures that all
necessary niches are filled so that the ecosystem may continue to function. Furthermore,
greater species diversity ensures natural sustainability for all life forms because, as in all
networks, everything is connected in some way. One species benefits another and if an
environment was to become mono-populated it would be virtually impossible for all of
the mechanisms required to sustain a habitat to be fulfilled, resulting in the collapse of the
ecosystem and any species that depended on it. It has also been determined that with high
biodiversity, an ecosystem is likely to recover from a disturbance more quickly. For
example, if a hurricane disrupted the natural processes of two marshes, one with high
biodiversity and one with low biodiversity, the marsh with more biodiversity would
recover more quickly. Once it is recovered it can continue to perform its ecological
services.
Species richness is a term closely related to biodiversity – it is the number of
species present. This term differs from biodiversity in that it is merely the count of
species, and not the count of individuals belonging to those species. Species richness was
also taken into consideration when calculating our results.
The most prevalent bodies of fresh water on the UCF campus are ponds. A pond,
for the purpose of this study, is a body of fresh water that does not have an aphotic zone.
Ponds are the most practical locations to test biodiversity in this study because they are
relatively small and have fewer variables to control. The small size and sensitivity of
these fresh water habitats make effects on water quality easy to test and pollutants easy to
detect compared to other habitats. There are at least 15 ponds on the UCF campus so
there are enough treatments to make any findings significant. All treatments are in
relatively close in location to one another, and conditions are mostly consistent across the
campus, so independent variables are less likely to be consistent in all treatments. In this
study, two treatments are chosen of equal sizes that are within the same storm water
quadrant (Figure 3). In this way it is known that the water that enters these ponds is of the
same quality, and any differences in biodiversity and species abundance is the result of
the surrounding environment, and not of initial water quality. By controlling these
variables, we can ensure that the differences are a result of the type of landscaping that
surrounds the ponds.
Testing these ponds is important. If habitat degradation is detected early by testing
indicator species in the ponds that are not Florida Friendly, the proper measures may be
taken to prevent ecosystem collapse, and the loss of keystone species before a threshold
is breached. Improving the health of the UCF ponds will improve the health of the UCF
campus and improve the quality of the aquifer as well. The ponds that were tested are
Florida Friendly landscaped ponds, and ponds that are not landscaped in a FloridaFriendly manner.
’Florida Friendly’ refers to landscapes that protect natural resources through the
conservation of water, prevention of erosion, creation of wildlife habitat, and the
reduction of waste and pollution (Florida University, 2009). This type of landscaping
protects the waterfront with a maintenance free buffer zone, which provides wildlife
habitat. Since these buffer zones are maintenance free, there is no need to return to the
sites for trimmings and alterations. The zones can encompass up to 60% of the lake and is
composed of native and non-native Florida plants that can coexist with natives. The
proper landscaping, and a larger buffer zone around ponds, helps to absorb and filter
storm water run off before collecting within drainage sites. This natural filtering system is
important for the cleanliness and purity of the water cycles – urban and natural.
Stormwater runoff usually carries pesticides and fertilizers into bodies of water, which in
turn eventually appear in the aquifer (Florida Friendly Landscaping Program). Fertilizing
Florida friendly landscapes, although unnecessary, is done sparingly and without
exceeding the recommended amounts. The fertilizer chosen has low nitrogen contents,
and should be ones that do not harm or pollute, such as chicken manure (UCF Landscape
and Natural Resources). The plants within the buffer zones surrounding the pond are
planted for the purpose of preventing erosion as well as for filtration. No invasive plant
species should be within the ponds perimeter, for these plants require much more water
and fertilizer, which in turn is unhealthy for the water shed drainage. Florida Friendly
landscaping should help the overall health and water quality of these ponds, which should
in turn show more indicator species present.
‘Non-Florida Friendly’ refers to ponds that require many resources in order to
keep the pond landscaped. This includes invasive plant species, manicured grass, and
plants that would not naturally occur near a pond (Florida Friendly Landscaping
Program). These plants require much more fertilizer and watering than native species,
which is detrimental to the overall health of our aquifers and ecosystems.
Our objective was to determine whether there is more wildlife biodiversity in
Florida Friendly landscapes than landscapes that are not Florida Friendly. Our hypothesis
was that Florida Friendly landscapes are more ecologically sustainable, based on the
presence of indicator species. Based on our hypothesis, we expected to see in our results
that Florida friendly landscapes benefit the aquatic system in many ways. One example is
Florida Friendly landscapes key component, “right plant right place,” which is very
beneficial because native plants being placed in the right place help reduce the amount of
water needed to upkeep the landscape. The reason being is that native plant life cycles
benefit best from natural watering cycles (Dukes et al, 2013). Each factor is going to tie
into the success of each Florida Friendly landscape and aquatic system. Therefore, we
expected opposite results from our non-Florida Friendly landscapes. We predicted that
there would be limited indicator species encountered during visits as well as worse water
quality and minimal wildlife biodiversity.
All in all we hoped this study would benefit the eco-system as defined by Alaina
Bernard and Jennifer Elliot (2013) as the interrelated systems of the environment, the
economy and the people. When the people of Florida improve their landscaping practices,
the economy is strengthened by continual development and the environment is not
harmed and can continue to function and provide ecological functions for the people and
other species. This is how sustainable development may be achieved.
Methods
The amount of biodiversity was measured by sampling indicator species in both
Florida Friendly ponds and ponds that are not Florida Friendly. Each pond was surveyed
on Sunday, Monday, and Tuesday, at 8 a.m. and 8 p.m. The three ponds considered
“Florida friendly” landscaped ponds were compared to the three ponds that we labeled as
not landscaped in a “Florida friendly” manner. The ponds that we assessed are all on the
University of Central Florida campus (see Figure 4).
To begin, we placed randomly placed two minnow traps (Figure 5) in each pond.
The traps were placed one foot off of the shoreline, and parallel to the shoreline. We set
the traps at 8 p.m. in each pond, and then checked the following morning at 8 a.m. After
recording and calculating the data, we emptied the traps and reset them for the following
day.
After setting the traps, we walked the perimeter of the pond for ten minutes to
observe the surrounding area for wildlife. The time of day, weather conditions,
temperature, and other relevant information were documented. Vertebrates spotted within
a fifteen-foot radius of the pond were recorded. Dip nets were additionally used to
randomly sample species in six sectors around the perimeter of each pond shoreline
within the dense vegetation to identify tadpoles and larva in the pond.
During the observation period, we listened for vocalizations of indicator species
(typically frogs), and recorded the amount heard and the species. Vocalization data was
collected at the 8 p.m. shifts since this was when amphibian activity was most abundant.
Data was collected for six weeks, and then analyzed to determine the biodiversity
in each pond. The data from the Florida Friendly ponds and the non Florida Friendly
ponds were compared in order to obtain the results. Finally, we conducted a water quality
test for dissolved oxygen, nitrate, pH, and bacteria.
Results
Indicator Species Observed
The majority of our findings were based on observations, and at each of the six
ponds, different indicator species were found. At the Florida Friendly ponds, Lithobates
sphenocephalus (Southern Leopard frog), Hyla cineria (Green tree frog), Anaxyrus
terrestris (Southern Toad), Osteopilus septentrionalis (Cuban tree frog), and Rana
catesbeiana (Bull frog) were observed, while the non Florida Friendly ponds had some of
the same species but did not host Hyla cineria or Anaxyrus terrestris, but did have
Gastrophryne carolinensis (Narrow mouth toad).
The Florida Friendly pond at Garage H proved to be the pond that had the most
indicator species present. At one observation period, 56 indicator species were counted.
This is a much higher number than the other ponds; 12 indicator species were counted at
the Florida Friendly pond near the Arboretum, and 18 indicator species were the most
counted at the Florida Friendly pond near Lake Claire. The ponds that were not Florida
Friendly had a significantly lower number of indicator species observed at one time; the
pond near the softball fields had five indicator species observed, the pond near the
Student Union had seven, and the pond near Lake Claire had four. This number reflects
the number of indicator species observed at one observation time. This is an important
number to include because it gives a picture of how many indicator species could be at
one pond at any given time.
Water Quality
The water quality of each of the six ponds was tested using an Urban Water test
kit. Each pond was tested for bacteria, dissolved oxygen, pH, and nitrate. The results are
as follows:
Table 1: Florida friendly pond water quality
Florida
Friendly
pH
Dissolved
Oxygen (ppm)
Nitrate (ppm)
Garage H
Quadrant 1
6
4
Arboretum
Quadrant 2
6.8
6
Lake Claire
Quadrant 3
7
7.5
Average
2
3
2
2.33
Table 2: Not Florida friendly pond water quality
Not Florida
Friendly
pH
Dissolved
Oxygen (ppm)
Nitrate (ppm)
6.6
5.83
Softball
Quadrant 1
6
6
Student Union
Quadrant 2
6.5
5
Lake Claire
Quadrant 3
6.2
4
Average
4
3
4
3.67
6.23
5
The bacteria at each of the six ponds all tested positive, so the data was left out of
the charts. Visible in table 1, the Florida Friendly ponds had a higher pH on average
compared to the not Florida Friendly ponds, visible in table 2. The Florida Friendly ponds
also had a higher average of dissolved oxygen, at 5.83 ppm compared to the not Florida
Friendly’s average of 5 ppm. The nitrate parts per million in the Florida Friendly ponds
had an average of 2.33, while the not Florida Friendly ponds had a higher average at 3.67.
The minnow traps were used in hopes of trapping indicator species, but it was
generally unsuccessful. The minnow traps mostly caught small fish, crawdads, and
insects. Only one indicator species was caught; a bullfrog at the not Florida Friendly
pond near Lake Claire. Because of the limited number of indicator species found in the
minnow traps, this method was not a major source of our data collected.
Biodiversity calculations
The numerical value of biodiversity is represented by D. The range is 0-1 and the
lower the number the more biodiversity at that location. To determine this value we used
the Simpson’s Index equation: D=(sum of(ni(ni-1)))/(N(N-1))
D being biodiversity, ni being amount of individuals in a species and N
representing the total number of all individuals.
Biodiversity for Florida Friendly ponds, as seen in table 3, was as follows; .629,
.567, .340 with Garage H having the most biodiversity (lowest number) and Lake Claire
having the least biodiversity (highest number). The ponds that were not Florida Friendly
had more biodiversity, with only the least diverse pond having less biodiversity than the
most diverse Florida Friendly pond. The biodiversity for the ponds that were not Florida
Friendly, as seen in table 4, was as follows; .388, .267, .269. The softball pond had the
most biodiversity with the lowest number of .267 and of the not Florida Friendly ponds
the Student union pond had the least biodiversity (highest number).
Table 3: Florida friendly pond biodiversity
Florida
Friendly
Biodiversity
Garage H
Quadrant 1
.340
Arboretum
Quadrant 2
.567
Table 4: Florida friendly pond biodiversity
Not Florida
Friendly
Biodiversity
Softball
Quadrant 1
.267
Student Union
Quadrant 2
.388
Lake Claire
Quadrant 3
.629
Lake Claire
Quadrant 3
.269
As for individuals counted, the Florida Friendly ponds far outnumbered the ponds
that were not Florida friendly. With the Arboretum pond having 62, Lake Claire having
103, and Garage H having 305. The ponds that were not Florida Friendly did not have as
many individuals with Lake Claire having 30, Student Union having 34, and the Softball
field pond having 40. In total, Florida Friendly had 470 organisms observed while the
other ponds totaled 104.
These were not our anticipated results. These results are complicated because
even though the Florida Friendly ponds had much more abundance of indicator species
and theoretically should be able to support more species, there was less biodiversity. This
brings up a new question. Which is more important when judging ecosystem health; the
number of individuals present or the biodiversity?
Discussion
Indicator Species
Florida’s freshwater ecosystems are abundant with wildlife, serving as habitat to
an array of fish, amphibians, aquatic mammals, birds and vegetation. These freshwater
environments are imperative for the ecosystems of Florida. There are over 100
documented freshwater fish species in the South Florida region alone (Florida Museum of
Natural History). According to the University of Florida the most prevalent species in
Florida wetlands are amphibians. There are 78 documented species of amphibian and
reptile species in Florida’s freshwaters (Krysko et al., 2011) suggesting that there is
diversity as well as abundance in these ecosystems.
Although these numbers may persuade some that Florida freshwater ecosystems
are flourishing, the truth is that these environments are extremely sensitive. According to
the Florida Fish and Wildlife Conservation Commission 2013 report on Florida’s
Endangered and Threatened Species there are a total of 66: fish (14), amphibians (6),
reptiles (24), and invertebrates (22) that are listed as endangered or threatened. Most of
these species live or directly rely on Florida freshwater habitats. Without these studies
and others like them, the decline of these species is likely to go unnoticed and could lead
to degradation, or collapse, of the ecosystems they participate in. That is until more dire
consequences are noticed such as the inability of some freshwater ecosystems around the
world to provide ecosystem services. This is most obvious where humans are most
dependent on them, in the developing world. Changes in development and agriculture
have caused a decline in water quality and quantity, leading to many deaths (Foley et al.,
2005).
Having knowledge of the consequences and relative ease of the collapse of
freshwater systems it is a wonder that virtually all freshwater environments that are in
developed areas are manipulated in some way by people. Freshwater ecosystems can be
affected by runoff of fertilizers, changes in surrounding vegetation and soil, presence of
nonnative species and of course the manipulation of the freshwater body itself. For
example, the UCF campus has been developing since 1963 and has been manipulating
their freshwaters ever since (Refer to Figure 1, 2). Efforts such as Florida Friendly
Landscapes have been made to lessen or even eliminate any negative impact campus
development may have on the freshwater ecosystems.
This matter is of dire importance because indicator species “provide early
warning of environmental impacts through natural response” (Carigan and Villiard,
2001). Although our anticipated results were not reached, the value of this project still
held some integrity. Indicator species biodiversity may have been found to be lower for
the chosen Florida Friendly Landscapes, but the species richness of indicator species was
found to be greater for the selected ponds. According to Colwell and Gotelli (2001),
species richness is “a fundamental measurement of community and regional diversity,
and it underlies many ecological models and conservation strategies”. Species richness
may be “the simplest way to describe community and regional diversity (Colwell and
Gotellie)”, but quantifying species richness is even more important. Not only for simple
comparisons among survey sites, but also for addressing the concentration of local
communities colonized from regional hubs. As Colwell and Gotelli state, “maximizing
species richness is often an explicit or implicit goal of conservation studies”.
Through hours of observations, it was theorized that “right plant, right place” played
an important role in indicator species richness. We observed many correlations between
certain indicator species (frogs) and certain species of plants. No previously written
documentation of these specific correlations were found, so we are relying solely on our
own observations of these specific species and their specific placements around UCF’s
storm water ponds. At garage H, it was observed that green tree frogs (Hyla cinarea)
were amongst the most prolific of the indicator species, this also happened to be the only
pond where H. cinerea was observed. During both our daytime and nighttime visits to
Garage H, the majority of the H. cinerea found were on or around the branches and
leaves of star anise (Illicium verum). This also happened to be the only pond where I.
verum was present. It was also observed that I. verum leaf color was very similar if not
identical to the normal color expressed by H. cinarea. This with the combination of being
the thickest of foliage was believed to create the optimum micro-habitat for H. cinarea.
Other correlations were observed as well, one being the correlation between pickerel
weed (Pontederia cordata) and the abundance of southern leopard frogs (Lithobates
sphenocephalus). L. sphenocephalus was the most commonly observed indicator species,
but the highest densities of L. sphenocephalus were observed along ponds where P.
cordata present. Our theories for this being that P. cordata, provided optimum shelter
from harsh sun and predators for L. sphenocephalus and possibly a place for propagation
since, freshly metamorphasized individuals were found near P. cordata. Correlations
between southern toads (Anaxyrus terrestris) and wire grass (Arstida stricta) were also
noted.
Indicator species are important when considering human impacts on our
environments and the further correlation to sustainable action. When we release
pesticides and fertilizers and other toxins into our environments, they get washed away
into our water systems, and subsequently, pond systems. These pollutants degrade our
water systems by creating a poor water quality that many plants and animals cannot
thrive in. This destroys ecosystems, beginning with indicator species and working its way
up to affect other species. Consequently, the biodiversity of these systems is lowered and
suffers because it is no longer healthy enough to support multiple species. Worldwide
amphibian decline has caused many advocates of the environment to want to test air and
water quality to determine the sources of pollution. Urban areas are common test sites
due to the heavy anthropogenic influences these areas have (Beebee and Griffiths, 2005).
In Florida, urban freshwater systems are commonly tested.
Water Quality
The aspects of water quality were chosen because they were the most indicative
of the overall water quality of the ponds that we were observing. The first test, nitrate,
was performed to determine if there were high amounts of waste or chemicals in the
water. Nitrates typically enter water systems though fertilizer runoff and while nitrogen is
important for plant growth, high levels of nitrogen are detrimental because it stimulates
the growth of algae and cyanobacteria. This causes hypoxic conditions that can lead to
eutrophication (Briand et al., 2003). This begins to absorb and take the oxygen out of the
water; slowly killing off all other animal life in the water, including plants on the pond
floor that are unable to get sunlight after algae creates a surface cover. For the tests that
were performed, nitrate levels fewer than four are considered to be healthy for freshwater
systems and are desired in order to maintain a healthy aquatic system. On average, the
Florida Friendly ponds that were tested showed healthier nitrate levels than the NonFlorida Friendly ponds. This could possibly be attributed to the Florida Friendly ponds
having more plants and landscaping around the perimeter of the pond and the edges of
the water that could help to filter out high levels of minerals and toxins out of the water.
The Non-Florida Friendly ponds also had higher population levels of fish, which could be
responsible for increased waste that could increase nitrate levels.
The next test was for the dissolved oxygen levels in the ponds. According to the
U.S. Geological Survey, in aquatic systems, flowing water has higher dissolved oxygen
levels than stagnant water because the flowing and rushing of the water allows oxygen to
mix in and creates better circulation throughout the system (Perlman, 2013). However,
since ponds are stagnant ecosystems, maintaining a healthy dissolved oxygen level can be
a challenge. A dissolved oxygen level around 5 is required for the growth of aquatic
systems. However, when algae blooms and bacteria are abundant, or when organic matter
decays in the water, this uses up the available oxygen and chokes any other surrounding
plants or animals trying to live in the pond. Without sufficient levels of dissolved oxygen,
life in pond environments cannot be sustained and will die off because aquatic plants and
animals require dissolved oxygen in the water to survive.
The third test was for pH to determine how soluble nutrients in the water are, and
therefore how much can be taken up or absorbed by organisms in the water. A high pH
creates nutrient deposits in the water whereas a low pH causes nutrients to dissolve into
the water (Perlman, 2013). Seeing as pollutants and other toxins can alter the pH of
aquatic systems, this can also help to determine the solubility of these pollutants in the
water, and therefore how much of this is being absorbed by organisms in the water,
which can cause health problems and is also a major stressor on animal and plant life in
general (Bonga, 1997). An average pH of 7 is required to healthy freshwater ecosystems.
More importantly, a stable pH is preferred because organisms in the water become
accustomed to these levels and a slight change in either direction can cause health
problems for fish or plant life, possibly sending them into shock. The pH of all of the
ponds tested was adequate, however, on average, the pH of the Florida Friendly ponds
was closer to the optimal level of 7 than the average pH of the Non-Florida Friendly
ponds.
These three tests were important in indicating the water quality and overall health
of the aquatic pond systems that we observed because they build off of an effect each
other. For example, typically poor nitrate levels cause lower dissolved oxygen levels,
which will lower the pH, and this will be harmful to anything interacting in the water.
This happens anytime pollutants such as fertilizers or other chemicals enter the water,
causing high nutrient loads that create or add to poor water quality and adding to an
unhealthy ecosystem which disrupts the entire ecosystem cycle, including water and
nutrient cycling (Fenn et al., 1998). Because indicator species, such as frogs, have
permeable skin that they can breathe through, the health and abundance of their
populations is typically a good indicator of pond health because unhealthy ponds will
have detrimental effects on frog populations. This has a domino effect on the entire
ecosystem by altering population after population, disrupting the food chain of the pond,
and killing off the majority of the species until the pond too may die.
From our results, the average nitrate, dissolved oxygen, and pH levels from the
Florida Friendly ponds were healthier than the Non-Florida Friendly ponds. This could
possibly be attributed to the types of plants surrounding the ponds at the edges of the
water that helped to filter the water and maintain an adequate water quality. Interestingly,
the Florida Friendly pond in quadrant 1, which had the highest observed number of
indicator species, also had one of the lowest levels of dissolved oxygen. This usually
results from an excess of organic waste or algae growth. However, seeing as this pond
also had a relatively healthy nitrate level, it is more likely that this particular pond had a
high oxygen demand that caused the dissolved oxygen to drop so low.
A water quality test that should have been completed was the test for phosphorus
levels in the ponds. Testing for phosphorus is important because, like nitrogen, it is a
nutrient that is desired for plant growth however, in large amounts it leads to algal
blooms and can cause eutrophication and hypoxia in ponds. Phosphorus also typically
enters water systems through runoff of fertilizers or other pollutants. Again, similar to
nitrogen, certain levels of phosphorus are required in freshwater systems for live to
thrive. However, it is when these levels get too high that dangers arise.
Although we believe our data to be accurate, relevant, and useful to our
experiment, there were some minor flaws that occurred. If this experiment were to be
conducted again, these items would be taken into consideration to result in a better
overall experiment.
First, frogs and toads are most abundant during spring. It is predicted that more
indicator species would have been observed if this experiment was conducted during the
spring. Also, frogs are ectotherms. This means that they rely on the surrounding
environment as a heat source. During our experiment, the weather varied. Some days it
was as hot at 90 degrees Fahrenheit, and other days it was as low as 50 degrees
Fahrenheit. We believe this skewed our results; we might have seen more indicator
species if the temperature was constantly hot. This is another reason this experiment
would be more successful in the spring months.
Another factor that affected our experiment was the way we placed our minnow
traps in the ponds. As stated before, two traps were placed in each pond, in random
places, parallel to the shoreline. A better method would have been to place all of the traps
in a pond at once, and rotate the traps each week. We believe this would have yielded
more indicator species. We also believe that baiting the traps would also give more
results.
Because our data was based primarily on observations, there is an amount of
human error that occurred. Even though we went in pairs to observe each pond to ensure
consistency, it is likely that not every single indicator species was counted. There may
have been some that we failed to see or identify correctly. There was also limited access
to the perimeters of the ponds. Some ponds had heavy vegetation while other ponds were
simply too big to cover the entire perimeter in our allotted ten minutes of observation.
This resulted in observations being taken around the same parts of the ponds each time.
Because of this, we are unsure if there are more or less indicator species present at the
parts of the ponds that were not observed. However, we still believe that our data is
relevant because our methods were consistent throughout our experimentation.
Conclusion
Returning to the earlier question of, ‘Which is more important when judging ecosystem
health; the number of individuals present or the biodiversity?’ Both aspects are equally
important. The number of species needs to be taken into account, but also the individuals
of these species. Just because there are a few individuals of each species does not
necessarily mean that ecosystem is healthier than one with many individuals of a couple
different species. Both of these aspects need to be taken into account when judging the
health of an ecosystem.
If indicator species populations are degrading, this is a cause for alarm concerning
the health of the entire ecosystem and all that it supports. Negative impacts on
communities of indicator species in a pond environment “can have potentially longlasting implications for higher-level consumers such as wading birds” (Main, Ceilley &
Stansly, 2007) that will be affected from any alterations that will take place after a
disturbance in a lower animal community reaches its way up to the larger animal
communities. Essentially, indicator species have become “useful for detecting changes in
overall habitat structure and complexity” (Theel, Dibble & Madsen, 2008). If more effort
isn’t put into the preservation of these seemingly small and unimportant species and our
fresh water supplies, a domino effect will take place, quickly passing through the food
chain until it reaches human kind – negatively affecting agriculture, the livestock
industry, and finally reaching our vital water sources.
Appendix
Figure 1: The UCF campus in 1963.
Figure 2: The UCF campus in 2012
Figure 3: The UCF stormwater quadrants
Figure 4: Florida Friendly landscaped ponds are highlighted in green, while not Florida
Friendly landscaped ponds are highlighted in red.
Figure 5: Example of minnow trap that was used
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2013, from http://www.flmnh.ufl.edu/fish/.
Florida University Institute of Food and Agricultural Sciences. (2009). The florida yards
and neighborhoods Handbook. Retreived September 20, 2013
from http://www.floridayards.org/.
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in the measurement and comparison of species richness. Ecology Letters, 4: 379–
391.
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urbanizing world: A review. Biological Conservation, 141, 2432-2449.
Hoyer, M. V., Jackson, M. W., Allen, M. S., & Canfield, D. E. (2009). Lack of exotic
hydrilla infestation effects on plant, fish and aquatic bird community
measures. Lake and Reservoir Management, 24, 331-338.
Jensen, D.B., M. Torn, and J. Harte, "In Our Own Hands: A Strategy for Conserving
Biological Diversity in California," 1990.
Krysko, K.L., K.M. Enge, and P.E. Moler. 2011. Atlas of Amphibians and Reptiles in
Florida. Final Report, Project Agreement 08013, Florida Fish and Wildlife
Conservation Commission, Tallahassee, USA. 524 pp.Landres, P. B., Verner, J.,
& Thomas, J. W. (1988). Ecological uses of vertebrate indicator species: A
critique. Conservation Biology, 2 (4), 316-328.
Main, M. B., Ceilley, D. W., & Stansly, P. (2007). Freshwater fish assemblages in
isolated south florida wetlands.Southeastern Naturalist, 6(2), 343-350.
Nystro, P., Hansson, J., Mansson, J., Sundstedt, M., Reslow, C., & Brostrom, A. (2007).
A documented amphibian decline over 40 years: Possible causes and implications
for species recovery. Biological Conservation, 138, 399-411.
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from http://ga.water.usgs.gov/edu/dissolvedoxygen.html
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from http://ga.water.usgs.gov/edu/ph.html
Theel, H. J., Dibble, E. D., & Madsen, J. D. (2008). Differential influence of a monotypic
and diverse native aquatic plant bed on a macroinvertebrate assemblage; an
experimental implication of exotic plant induced habitat. Hydrobiologia, 600, 7787.
Herbicides 1
A Chemical Analysis of Organic Herbicides
By:
Danielle Rudley
Theresea Neumann
John Guziejka
Chad Bass
Dayanah Auguste
Photo courtesy of: Henry’s Fork Cooperative Weed Management Area
Herbicides 2
Introduction
Herbicides are a common way of eradicating unwanted plant growth. There are
several herbicides on the market; however there is a perceived trade-off between
effectiveness and sustainability.
One of the most widely commercialized herbicides in the world is glyphosate
(Vivancos 2011). It is considered “virtually ideal” because of its broad spectrum and its
supposedly low toxicity (Duke and Powles 2008). It kills plants by inhibiting the shikimic
pathway (Vivancos 2011). This pathway is responsible for producing aromatic amino
acids such as tryptophan and tyrosine. Glyphosate-induced alteration of amino acid
metabolism allows the plant to accrue greater levels of antioxidant enzymes (Vivancos
2011). The plant photosynthesis pathway becomes severely reduced. It leads to oxidative
stress for the plant, thus showing a strong correlation between amino acid metabolism
and cellular redox state, which is dependent upon a balance between processes that
require energy and processes that use energy (Vivancos 2011). Laboratory tests with
human and animal cells suggest that glyphosate or glyphosate-containing herbicides
cause genetic damage in both (Cox 2004). Several studies show that glyphosate alters the
production of sex hormones. Glyphosate can mimic the estrogen hormone, which plays
an important role in human reproduction. There have been several studies on the effects
of glyphosate and practically every study shows that glyphosate causes genetic damage
and even abnormal development in frogs (Cox 2004).
Juglone or 5-hydroxy-naphtalenedione is a compound that is derived from the
leaves, roots and bark of species of plants in the Juglandaceae family. It is sometimes
used as an herbicide but traditionally it is used as a natural dye for fabric and clothing.
Herbicides 3
It’s initial form is hydrojuglone and becomes juglone when it comes into contact with air
or soil (Shrestha 2009). Specifically, Black Walnut (Juglans nigra) is a plant that has
allelopathic effects on other plants in that it is extremely toxic and negatively affects
ATPase (which is imperative for cell metabolism) as well as decreases photosynthesis in
leaf tissue (Shrestha 2009). It is thought to act as a respiration inhibitor by withholding
the needed energy for metabolic activities (Black Walnut Toxicity). Similarly to
glyphosate, it also affects aquatic plants (Shrestha 2009).
Figure 1. Leaves and roots of Juglans nigra
Photo courtesy of: Exploring the world of trees…a tree species blog; Hilton Pond Center for
Piedmont Natural History
Juglone has been isolated and is commercially used in several products ranging
from dietary supplements to skin care. The debate continues as to whether juglone is
toxic to people. It is found to affect horses when used in their bedding material and
causes some allergic reaction when pollen is shed (Funt & Martin). One of the known
targets of juglone is the enzyme peptidyl-protyl isomerase or Pin1. P53 is a tumor
suppressor in human and animal cells that is activated after DNA damage, while H2Ax is
one of the several genes encoding the histone H2A. Peptidyl-protyl isomerase plays a role
Herbicides 4
in the stabilization and activation of p53 following damage to DNA. The natural toxin
juglone causes degradation of p53 and induces rapid H2Ax phosphorylation and cell
death in human fibroblasts. If juglone inhibits transcription then it also induces p53 and
inhibits Pin1, thus reducing the body’s ability to fight tumor formation (Paulsen &
Ljungman 2005). According to the German Commission E. Report, daily use of
products that contain juglone are connected to increased risk of cancer of the tongue and
leukoplakia of the lips (Paulsen & Ljungman 2005). Juglone also seems to inhibit the
protein kinase C which phosphorylates other proteins such as serine (Paulsenn &
Ljungman 2005). Juglone is found not to be safe because it can penetrate the plasma
membrane and causes polarization by blocking potassium channels (Cox 2004).
Figure 2. Leukoplakia of the tongue.
Photo courtesy of: dermRounds
Dermatology Network
Figure 3. Aerial Dioscorea bulbifera
Photo courtesy of: John
Air potato, Dioscorea bulbifera, is a non-native vine plant species that originally
came from both Asia and Africa (Wheeler et al 2007). Although air potato’s initial
immigration path to Florida is unclear, its earliest documentation is 1905 (Air Potato Task
Force 2008). Because air potato is an herbaceous, perennial twining vine it is very successful
at climbing on native vegetation and destroying what lies beneath it. Air potato is easy to
identify with its broad ovate-chordate leaves that have three main nerves that reach from the
Herbicides 5
base of the leaf to the tip. The vine reproduces through bulblike growths; these aerial tubers
called bulbils and are what give the vine its common name of air potato. The common name
however, is misleading because the bulbils that are produced are not
edible and can cause nausea if consumed due to the presence of
cyanogens and dioscorine, a toxic alkaloid (Air Potato Task Force
2008). This plant was once considered an ornamental species but is
now considered to be one of the most
aggressive weeds (Tear 2004), and because air potato is able to
Figure 4. Tuber of
Dioscorea
thrive
in abulbifera
variety of environments it has been found in several other states including
Courtesy of: John
Mississippi, Louisiana, Texas, and Hawaii (Wheeler et al 2007). Air potato is currently listed
as a category I noxious weed by the Florida Department of Agriculture and Consumer
Services (FLEPPC 2011) and it is vital that we begin to take back control from this species in
order to protect our native plant communities.
Earpod Tree, Enterolobium spp., is native to Central Mexico and northern areas of
South America but has now made its way over
to Central Florida (Broschat 2007) and is
newly considered to be an invasive species at
UCF. The earpod tree is a fast growing, large,
and drought tolerant, ornamental deciduous
tree common in Costa Rica that is only
Figure 5. Earpod transplant speimens in Toedter’s
truck. Photo courtesy of: John
considered invasive in certain conditions
(Rocha and Aguilar 2001). While it is no longer included on the Florida Exotic Pest Plant
Council’s invasive species list, the earpod tree is considered invasive according to UCF’s
Herbicides 6
Landscape and Natural Resources Weed Management Plan (UCF LNR 2010). Currently at
UCF the earpod tree population is quickly increasing and out competing natives and
disrupting native plant communities in highly valued areas on campus (UCF LNR 2010).
This species has become a high priority to control because of its rate of expansion and
disruption to native plant species. These trees are also sometimes removed due to their low
wind resistance, which is not conductive in Florida with our hurricane season. Earpod trees
can be easily identified by their distinctive hard seed pods that are shaped like a human ear,
thus where it gets the common name earpod tree. The leaves are doubly-compounded and the
tree also produces many small white flowers (Culbert 2007). Although earpod tree may not
be considered as invasive as air potato it is still very
important to develop an effective way to reduce the
population around the UCF campus in an attempt to
preserve our many diverse ecosystems around the
campus.
The reason we have chosen these two invasive
species for this experiment is because of their
difference in plant type. Air potato is a vine species
while the earpod tree is a woody plant species. Using
two different plant types allows us to see how each
Figure 6. Earpod specimens in the field
plot. Photo courtesy of: John
herbicide works on varying plant types. Glyphosate is labeled to work on grasses, broadleaf,
and woody plants while juglone works well on many types of broad-leaved forbs but most
grasses and some woody species can tolerate juglone.
Herbicides 7
Based on the information we have gathered we believe that the organic herbicide,
juglone, will be just as effective at eradicating invasive species as the non organic herbicide,
glyphosate.
Methods
The procedure will require air potato vines and earpod trees to be planted in a natural
setting as well as a laboratory to ensure the validity of the data. The two plants will be treated
with two different herbicides, varying in low, medium, and high concentration levels. These
varying concentrations will allow us to view the potential efficiency of the herbicides; for
example, while juglone might be effective, if it must be used at much higher concentrations
than glyphosate, it may not be worth the trade-off.
Table 1. Concentration amounts for each herbicide
Herbicide
Low Concentration Medium
Concentration
1x: 0.00365g/liter
20x: 0.075g/liter
( 0.000365%)
(0.0075%)
High
Concentration
30x: 0.1095g/liter
(0.01095%)
Glyphosate
.64 oz/.5 gallon
1.92 oz/.5 gallon
3.2 oz/.5 gallon
(Synthetic)
(1%)
(3%)
(5%)
Juglone (Organic)
There will be 48 specimens in the natural setting, with three control specimens for
each variable in the field. There will be 32 specimens in the lab setting and two controls for
the lab plot. Therefore there will be a total of 80 specimens. The synthetic herbicide chosen
will be glyphosate, and the organic herbicide will be juglone.
Herbicides 8
Table 2. Number of replicates per concentration of each herbicide for both Air Potato and Ear Pod,
respectively.
Field plants
Juglone (Org)
Glyphosate
(Syn)
Lab plants
Juglone (Org)
Glyphosate
(Syn)
None
3x
3x
Low
3x
3x
Medium
3x
3x
High
3x
3x
None
2x
2x
Low
2x
2x
Medium
2x
2x
High
2x
2x
The herbicides will be applied to the plants once and repeated as necessary. We will
observe vegetation changes over a five-week span by our research team in order to obtain
results. Pictures will be taken
weekly to document the mortality
rate of the invasive plants. The
same will be done within the lab
to analyze the difference in a
controlled setting against a natural
one. In the field we will require a
set of materials including:
Figure 7. Collecting Air Potato specimen for the lab plots
1. Juglone
2.
Glyphosate
3. Herbimax Oil Surfactant and Adjuvant
4. Tracker (admiral liquid)
5. Invasive species of plant
 Air potato
 Earpod Tree
Herbicides 9
6. Solo Accupower 416 5gal Backpack Sprayer
7. Chemical hand sprayer 32oz
8. Snake chaps
9. Camera (documentation of plant reciprocation)
10. Designated plots
11. Chart (representing plant growth or stunt)
12. ArcGIS mapping
Figure 8. Plot areas for treatment
Courtesy of: Jason Toedter
The lab in located on UCF campus in the biology greenhouse. The plots will be
designed to mimic the plots and setup in the field. The specimens in the lab will be treated
with the same herbicides but in a sterile environment, therefore will require
1.
2.
3.
4.
Gloves
Goggles
Clean plots (to ensure no cross contamination to ensure results)
Shovels (for transplanting lab plots)
Herbicides 10
Once the air potato and earpod tree were transplanted and moved to the lab plots the
experiment was ready for the application of herbicides. Two days passed and when we
arrived at the plot to continue the experiment we realized that most the air potato and some
earpod were dying before the application of herbicides. To combat this situation we decided
to reduce the amount of plant replicates from three to two and make sure the plants we
transplanted were healthy enough to survive the transition.
Data Analysis
We will begin to analyze the data by conducting observations twice a week. When we
arrive to our designated plots we will first capture a photo and document any observable
changes. Qualitative changes will be recorded according to:
‐
Plant Height (We will measure the plant height to determine if the species is growing,
shrinking, or stable).
‐
Coloration (We will observe the coloration of the species and compare it to control to
help determine the effects of the herbicide).
‐
Species per plot (We will count the species within the plot to determine if they are
reproducing, stable, or dying off).
All of the observations made will help us categorize the species on a scale of 0-3 with
the use of decimals if needed. This scale will help us formulate graphs to show the life cycle
of the species within the plot.
0: Death, species no longer shows any signs of life.
1: Poor, Species are still alive but show signs of death. Plant is brown, withered, limp, and is
approaching end of life.
Herbicides 11
2: Fair, Species is alive but is beginning to show signs of deterioration. Leaves are beginning
to brown; plant growth is slowing or has already stopped.
3: Excellent, Species is thriving, showing growth, lush, green, and shows no sign of
deteriorating.
Field Data Results:
Glyphosate application to the Air potato, Dioscore abulbifera:Following the
application of glyphosate on November 16, 2012, the air potato resulted in a 100% death rate
with all concentrations. The control specimen with no herbicide application remained in good
health. (Table 3)
Juglone application to the Air potato, Dioscorea bulbifera: After the application of
Juglone, the species resulted in a 100% death rate at the low and medium concentrations. The
high concentration yielded a death rate at 67 percent. (Table 4)
Glyphosate application to The Earpod Tree, Enterolobium spp: Glyphosate resulted
in 0% death with all concentrations of herbicide. All concentrations had an effect on the
species but no concentration ultimately lead to death.
Juglone application to The Earpod Tree, Enterolobium spp:,The application of
Juglone, resulted in 0% death at all concentrations. The low concentration showed the
greatest signs of death followed by the medium and high concentrations.
Herbicides 12
Table 3: Life cycle of Air potato, Dioscorea bulbiferain a natural setting following the application of
Glyphosate on November 16, 2012.
Table 4: Life cycle of Air potato, Dioscorea bulbiferain a natural setting following the application of
Juglone on November 6, 2012.
Herbicides 13
Lab Data Results:
Glyphosate application to the Air potato, Dioscorea bulbifera: Following the application
of glyphosate the air potato resulted in a 100% death rate at all concentrations. The control with
no herbicide application showed a 0% death .
Juglone application to the Air potato, Dioscorea bulbifera: Juglone resulted in a
100% death at all concentrations. The control specimen showed no signs of death.
Glyphosate application to The Earpod Tree, Enterolobium spp: Glyphosate resulted
in 0% death at all concentrations. The high concentration of glyphosate produced the highest
signs of death between all concentrations. The control specimen showed no signs of death.
Juglone application to The Earpod Tree, Enterolobium spp:,Juglone resulted in 50%
death for the low concentration, 0% death for medium and high concentrations. The low
concentration of herbicide resulted in the highest rate of death. The control species had 0%
death.
Table 5 : Life cycle of Air potato, Dioscorea bulbifera in a natural setting following the application of
Juglone on November 6, 2012.
4
3
2
1
0
6‐Nov 13‐Nov 20‐Nov 27‐Nov
Juglone
(none)
Juglone (Low)
Juglone
(Med)
Herbicides 14
Table 6: Life cycle of The Earpod Tree, Enterolobium spp in a natural setting following the application of
Glyphosate on November 16, 2012
Table 7: Life cycle of Air potato, Dioscorea bulbiferain a lab setting following the application of Juglone
on November 6, 2012.
3.5
3
2.5
2
1.5
1
0.5
0
6‐Nov
Juglone (none)
Juglone(low)
Juglone (Med)
Juglone (High)
13‐Nov 20‐Nov 27‐Nov
Herbicides 15
Table 8: Life cycle of The Earpod Tree, Enterolobiumspp in a lab setting following the application of
Juglone on November 6, 2012.
4
3
2
Juglone
(none)
Juglone (Low)
1
0
6‐Nov 13‐Nov 20‐Nov 27‐Nov
Juglone Med)
Discussion
The least expensive herbicide for the air potato plants in the field was juglone at a low
concentration (Table 9). It was just as effective as the medium concentration with a 100%
death rate, however the medium concentration killed the plants at least 4 days earlier (Figure
9). This is only significant in effectiveness
if time is a major constraint.
The most effective herbicide for
ear pod trees in the field plots was
glyphosate at a medium concentration
(Table 9). However, a greater decline in
Figure 9. Juglone at medium concentration applied
to Dioscorea bulbifera
health was seen in the low and high
concentrations of juglone. The cost of the low concentration of juglone was less than half of
the medium concentration of glyphosate. It is interesting to note that of the ear pods in the
Herbicides 16
field plots, the controls for the glyphosate group had the greatest overall decline in health
(Figure 10). This suggests either too close of a proximity to the ear pods that were sprayed,
or other climatic factors.
The least expensive herbicide for the air potato plants in the lab was juglone at a low
concentration (Figure 11). The organic high concentration killed the plants at least 4 days
earlier than the low concentration (Table 3), but as mentioned earlier,
this is only significant in effectiveness if time is a major constraint.
Figure 11. Air potato shortly
after juglone application
Figure 10. Ear pod control for
glyphosate
The most cost effective herbicide for the ear pods in the lab was the juglone at a low
concentration (Table 4). It had the same death rate as the synthetic herbicide at a medium
concentration, but with a greater decline in health.
Table 9. Most effective herbicide per plot variable; least expensive herbicide between the most effective
concentrations per herbicide
Most effective
Least Expensive
Ear Pod Field
Glyphosate- Medium concentration:
%33 death %56 decline
Juglone- Low concentration: $2.01
Ear Pod Lab
Juglone- Low concentration:
%50 Death %92 decline
Juglone- Low concentration: $1.34
Air Potato Field Juglone- Low concentration:
%100 death %100 decline
Juglone- Low concentration: $2.01
Air Potato Lab
Juglone- Low concentration: $1.34
Juglone- Low concentration:
% 100 death %100 decline
Herbicides 17
In every variable, the organic herbicide has proven cheaper; the most expensive
concentration of organic herbicide is less than half the cost for the cheapest concentration of
the synthetic herbicide. For most variables, the organic herbicide was proven more effective
in killing plants, and when the synthetic herbicide had a higher death rate, plants sprayed
with the organic herbicide still had a greater overall decline in health.
Table 10. Cost of each herbicide according to concentration level
Low
Medium
High
concentration concentration concentration
Organic all plants
$6.68
$6.94
$7.06
Synthetic all plants
$15.12
$15.92
$16.72
Organic per plant
$0.67
$0.69
$0.71
Synthetic per plant
$1.51
$1.59
$1.67
Some of the barriers that may have affected the outcome include plant locations,
recent weather patterns, and cross contamination of herbicide concentration. The lab plants
were first placed in an area of lower elevation than its surroundings. Precipitation would
create small pools, decreasing the health of the air potatoes. The plants were then moved to a
higher elevation where water could not accumulate. Hurricane Sandy caused a greater than
normal increase in precipitation, further decreasing the health of the lab plants. The hurricane
reached Florida October 29th, 2012; the large amount of wind also affected the plants and
even turned some lab specimens over. Luckily, there was no flooding in either the lab or field
plots.
Herbicides 18
Both herbicides inhibit the photosynthetic pathway of the plants (Vivancos 2011;
Shrestha 2009). As plants decreased in ‘health’, the first signs were yellowing and wilting of
leaves. The ear pods that were sprayed with glyphosate decreased only somewhat in health,
with a total of 2 plants dying that were sprayed. Glyphosate’s stated effectiveness is on grass,
sedge and broad-leaved species; this may account for its ineffectiveness as compared to air
potato (Cox 2004).
This experiment has shown that the organic herbicide juglone is just as effective at
eradicating invasive plants as its synthetic counterpart, glyphosate. There is no need to use a
synthetic substitute when a naturally occurring phytochemical fulfils the same utility.
Juglone is still a hazardous herbicide that should be used with extreme caution.
However, it is an option that allows for the most social equity. Monsanto is the producer of
Roundup, which is an herbicide whose main active ingredient is glyphosate. They also alter
their genetically modified crops to be resistant to glyphosate (Norsworthy 2012). This creates
both a hindrance in the economic development of farmers that use their seeds which produce
infertile offspring as well a disparity in social justice, since the farmers becomes reliant on
the corporation who originally sold them the seeds for another crop. With an option like
juglone, farmers are no longer dependent on these corporations.
The patent on glyphosate has expired, allowing for companies such as Bayer,
Syngenta and Nufarm to sell herbicide products that contain glyphosate (Brandli &
Reinacher 2012). China produces 400,000 tons of glyphosate annually, about half of total
global production (Brandli & Reinacher 2012). A study in Germany tested the urine of a
population in Berlin that did not previously come into any contact with the herbicide, and
Herbicides 19
found extremely high levels of glyphosate in their urine, about 5 to 20 times more than the
limit for drinking water (Brandli & Reinacher 2012). It is likely to be from the produce
consumed that was sprayed with glyphosate.
Humans have irrevocably altered native ecosystems all around the world. Invasive
species infiltrate healthy ecosystems from several venues, such as ballast water from ships
(Deacutis and Ribb 2002). Preventative measures are extremely helpful, however mitigation
methods have become a necessity. This research reinforces the potential for effective,
sustainable eradication of plants that threaten the integrity of UCF’s local biodiversity.
Herbicides 20
Literature Cited
Air Potato Task Force (2008). Air potato (dioscorea bulbifera) management plan,
Recommendations from the air potato task force. Retrieved September 22, 2012,
from Florida Exotic Pest Plant Council Management Plans:
http://www.fleppc.org/Manage_Plans/AirpotatoManagementPlan_Final.pdf
Brändli D, Reinacher S. “Herbicides found in Human Urine”.Ithaka Journal 1/ 2012:
270–272 (2012). www.ithaka-journal.net
Broschat, T.K., Meerow, A.W., Black, R.J. (2007). “Enviroscaping to conserve energy:
Trees for south florida.” Florida Cooperative Extension Service, Institute of Food and
Agricultural Sciences, University of Florida. 1-12.
Cox, Caroline. “Glyphosate.” Journal of pesticide reform. Volume 24:4. 2004
Culbert, D (2007, May). Right plant/Right place: A universal concept. Retrieved September
22nd, 2012. From University of Florida UF/IFAS Okeechobee County
Extension Service:
http://okeechobee.ifas.ufl.edu/News%20columns/Enterolobium.Ear.Tree.htm
Duke, S.O., S.B. Powles. 2008. Glyphosate: A Once in a Century Herbicide. Pest
Management Science. 64:319-325
FLEPPC. (2011). List of invasive plant species. Florida Exotic Pest Plant Council.
Retrieved September 22, 2012, from Florida Exotic Pest Plant Council:
http://www.fleppc.org/list/11list.htm or Wildland Weeds Vol. 14(3-4):11-14.
Funt, Richard C., J. Martin. “Black Walnut Toxicity to Plants, humans and horses.”
Horticulture and Crop Science: Ohio State University Extension Fact Sheet.
Hess, D.F., C.L. Foy. “Interaction of surfactants with plant cuticles.” Weed technology,
14(4):807-813. 2000..
Herbicides 21
Norsworthy, J.K., S.M. Ward, D.R. Shaw, R.S. Llewellyn, R.L. Nichols, T.M. Webster,
K.W. Bradley, G. Frisvold, S.B. Powles, N.R. Burgos, W.W. Witt, M. Barrett.
“Reducing the risk of herbicide resistance: best management practices and
recommendations.” 60(1):31-62. 2012.
Paulsen, M. T., M. Ljungman. “The natural toxin juglone causes degradation of p53 and
induces rapid H2Ax phosphorylation and cell death in human fibroblasts.”
Toxicology and applied pharmacology Volume 209. 2005
Rocha, O.J., Aguilar, G. (2001). Reproductive biology of the dry forest tree enterolobium
cyclocarpum (guanacaste) in costa rica: A comparison between trees left in
pastures and trees in continuous forest. American Journal of Botany, 88 (9),
1607-1614.
Shrestha, A. “Potential of Black Walnut (Juglans nigra) extract prodeuct (NatureCur) as a
pre- and post-emergece bioherbicide”. Journal of sustainable agriculture. 33(8):810822. 2009.
Tear, J. (2004). Identification and control of non-native invasive plants in east central
florida. [Brochure]. Brevard County Natural Resources Management Office.
Technical Resources International Inc... “Summary of data for chemical selection:
Juglone.” 481-39-0. 1999.
University of Central Florida Landscape and Natural Resources (2010, February).
University of central florida weed management plan. Retrieved September 22,
2012, from University of Central Florida Library Web site:
Herbicides 22
http://www.fp.ucf.edu/mp2010/PDFs/213%20Conservation%20_Weed_Manage
ment_Appendix_.pdf
Vivancos, P.D., S.P. Driscoll, C.A. Bulman, L. Ying, K. Emami, A. Treumann, C.
Mauve, G. Noctor, C.H. Foyer. “Perturbations of amino acid metabolism associated
with Glyphosate-dependent inhibition of Shikimic acid metabolism affect cellular
redox homeostasis and alter the abundance of proteins involved in photosynthesis
and photorespiration”. Plant Physiology, 157(1):256-268. 2011
Wheeler, G.S., Pemberton, R.W., Raz L. (2007). A biological control feasibility study of the
invasive weed-air potato, dioscorea bulbifera L. (dioscoreaceae): An effort to
increase biological control transparency and safety. Natural Areas Journal,
27(3), 269-279.
1
Summer Daze in Fall
Brooke Darden, Dominique Gray, Thomas Hagan, Alberto Vazquez, Iesl Yi
University of Central Florida, Department of Biology
Introduction
An urban heat island (UHI) is an area of land located in a thoroughly developed city that exhibits
higher temperatures than the surrounding land, which is a local problem with global effects. On a
local scale, urban development causes higher temperatures that persist over longer periods of
time. Globally, UHIs have a serious impact on atmospheric temperatures and world climate.
Several different phenomena are acknowledged as contributors to the increase in urban
temperature indexes. Oke established a list of possible causes: (1) amplified short-wave radiation
gain, (2) amplified long-wave radiation gain from the atmosphere, (3) decreased long-wave
radiation loss, (4) anthropogenic heat sources from within urban developments, (5) increased
heat storage, (6) less evapotranspiration, and (7) decreased turbulent heat transport [1][2]. Urban
environments tend to reflect more solar radiation than non-urban environments, which indirectly
leads to increased absorption of the reflected solar radiation by urban developments. In addition
to this increase in absorption of solar radiation, the increased pollution rates in the atmosphere
above urban cities magnify the level of solar radiation that reaches those areas. In areas that
experience a UHI effect, buildings act as obstructions that hinder the loss of long-wave radiation
(i.e. infrared heat waves) back into the atmosphere. Even human activity causes a rise in
temperature indexes, whether it be via vehicle use, industrial business, or endothermic activity of
living organisms (i.e. humans and pets). Materials used in construction of urban infrastructure
(i.e. concrete, asphalt) contribute to increases in storage of heat by the urban environment, while
lack of vegetation mitigates the cooling effects of evapotranspiration. Urban layout and
composition have a major effect on temperatures, especially in courtyard/parking lot settings,
where the absence of buildings or other tall structures that normally cause a wind-tunnel effect
results in relatively stagnant air movement patterns [3].
Figure 1. Possible causes of the UHI effect [3].
2
A UHI results in serious harm to a region by causing societal implications, natural environmental
degradations, and economic consequences. These effects, as summarized by the EPA, include
increasing energy consumption/demands, higher air conditioning costs, air pollution and
greenhouse gas emissions, heat-related illness and mortality, and decreased water quality [4].
More developed lands with surfaces consisting of asphalt and concrete prevent the absorption of
water by natural ground, allowing rainwater to leave the city area more rapidly than it would if
the land were undeveloped. This reduces the cooling effect of water and increases the
temperature of a UHI [5].
While urban development is shown to negatively affect surrounding areas, it is important to note
the benefits of efficient urbanization. High population and employment density can reduce the
consumption of energy, decrease vehicle miles traveled, and result in lower CO emissions per
person [6]. While these facts provide hope for the current global situation, unfortunately, the
reality of urbanization is disheartening. Urban land expansion occurs at rates greater than that of
urban population growth, indicating no evident increase in the efficiency of urban land use [7].
While urban development is expanding, it is not doing so in a way that benefits the populations
living there.
2
The detrimental effects of UHI are astounding. When Europe experienced a heat wave in 2003,
thousands of people died due to heat stroke and other heat-related illnesses [8]. In France, excess
deaths occurred compared to other years, particularly in the elderly population in Paris, the most
urbanized city in France [9]. It was also found those who lived in houses that are difficult to cool
were more susceptible to the detriments of the heat wave [9]. Though this relation between heat
and mortality does not support causation, the correlation is undeniable. The inequity experienced
by those with lower socioeconomic class and older age may be mitigated once the causes of UHI
are better understood.
The UHI effect is apparent at the University of Central Florida (UCF), as faculty and students
feel the heat radiating from the ground. This poses a health risk to the UCF population as well.
Situated in Orlando, Florida, the campus experiences a subtropical climate that is already
predisposed to high temperatures and humidity. As temperatures rise due to the UHI effect, the
risk of heat stroke is more prevalent.
The changes in temperature of UHIs affect all species in some way, often times by how they live
and eat. Specifically, red-shouldered hawks and red-tailed hawks cannot hunt as efficiently in
higher temperatures. At UCF, these raptors provide biological pest management; as they hunt
less efficiently, the rodent population on campus may increase to an uncontrollable level.
Another effect on the environment is the exposure of higher temperatures to the atmosphere.
This exposure, especially when considering the summation of all UHIs, contributes to global
temperature increases. Because of this, understanding and finding a solution for the UHI effect is
a vital step to mitigate climate change. However, there is a lack of conclusive research to support
the presence of a UHI effect at UCF. With the campus increasing urbanization each year, it is
dangerous to continue construction without more knowledge of its effects. Studying the
temperature and humidity indexes for various lands (natural and developed) on campus will
result in definite identification of a UHI effect and further allow campus facilities and
management to approve research that may find ways to reduce the UHI effect on campus.
3
Methods
Stewart published an important review critiquing modern UHI literature, in which he discussed
various criteria a UHI study must meet to be reputable and scientifically appropriate [10]. This
UHI study seeks to follow guidelines stated in the review. In addition to accurate
characterization of the UHI effect and explicit quantification of UHI effects on a local scale (in
the case of this study, the UCF campus), the review identified important standards in
methodology that contribute to an experiment’s integrity, from consistency of data collection to
accurate portrayal of surrounding areas of site selection [10].
In order to accurately measure the UHI effect at canopy level, 42 HOBO Pro v2 (U23-002) data
loggers will be mounted to various structures around campus (i.e. lamp posts, street signs, trees,
etc.), at 1-3 m height from the ground, depending on the individual data collection location, out
of reach of passersby. Temperature and relative humidity will be recorded at an accuracy level of
± 0.21°C from 0-50°C and ± 2.5% from 10-90% relative humidity, according to the HOBO Pro
v2 (U23-002) manual. Data collection locations will be determined by creating transects which
stem from the Student Union as the center of campus. The exact field sites will be representative
of the composition of the surrounding areas. Failure to accurately represent local-scale
environments, known as confusion of scales, can skew data readings and cause errors in results
[10]. Collection sites will be distributed across all of campus because it is important to ensure
that data is not extrapolated just for the purpose of creating temperature gradient maps. This
strategic transect method allows for the most even distribution of data collection and, therefore,
an accurate representation of temperature gradients across campus.
The UCF campus is comprised of 60% natural land and 40% developed area, but because this
study aims to identify a UHI effect and the transects will stem from the center of the developed
area of campus, more than 40% of data loggers will be located in urbanized areas of campus.
Temperature and relative humidity will be recorded every 2 hours for a time span of 6 weeks.
This extended period of data collection will account for discrepancies in temperature caused by
weather patterns and temperature fronts in the area. Field sites will be in areas with little change
in slope, and bodies of water that may be located near each site will be considered when
analyzing readings. Temperature readings will be taken at the same times for all collection sites
(± 1 minute per month, according to the HOBO Pro v2 U23-00x manual), because differences in
collection times could exhibit a time-induced heat island effect, as opposed to an urban-induced
heat island effect.
Upon completion of data collection, the dependent variables, temperature and relative humidity,
will be analyzed in relation to the independent variables, which include location on campus
(radial distance from center of campus), composition of the surrounding area (urban, hybrid, or
natural), time of day, and the date of data collection. These analyses will be used to determine
the effects of urban development on heat indexes and heat retention overnight.
4
Figure 2. Data
collection location
selection: Transect
overview
Three different transect
layouts designed
specifically to ensure
equipment that will
record variables are
placed at strategic and
equally-spaced
locations. Combined, the
transects will form the
final layout of collection
locations across campus.
5
Materials
Item
Purpose of item
42 HOBOPro v2 data loggers
For the continuous measurement and recording of
temperature and relative humidity at specific locations
HOBO shuttle
Data extraction device
Laptop
To download and organize data collected from the study
ArcGIS
To analyze data and make a thermal map of campus
GPS monitor
To ensure proper placements of the data loggers
Zip line measuring tape
To measure the distance between each data logger
Ladder
To reach inconvenient heights
Plastic zip ties
To attach data loggers to posts and trees
Nails
To attach data loggers on trees
Hammer
To insert nails into trees
Appropriate gear
Boots, long pants, long-sleeved shirts, hat (personal
preference), and gloves
Snake chaps
For protection from venomous snakes
Table 1: A list of materials and their purpose, none of which need to be purchased because they
are already available, making this a cost-free study.
Anticipated Results
A UHI effect will be found on the UCF campus. It is hypothesized that areas of urban
development will exhibit higher temperature readings and sustain these temperatures longer than
areas of natural land due to retention of heat in the asphalt and concrete. It is anticipated that
urbanized land will take at least two more hours to cool to the same temperature of natural lands
at night. Furthermore, natural lands are projected to be at least 2°C cooler than developed lands
during the day. Developed areas of campus with wider pavement canyons, such as the parking
lot behind the Health and Public Affairs buildings, will most likely experience higher
temperature readings than other developed areas.
6
References
[1] Oke, TR. (1982). The energetic basis of the urban heat island. QJR Meteorol Soc,
108(455). doi:10.1002/qj.49710845502
[2] Oke, TR. (1987). Boundary layer climates. 2nd edition. London: Methuen.
[3] Toparlar, Y., Blocken, B., Vos, P., Van Heijst, G., Janssen, W., Van Hooff, T.,
Montazeri, H., & Timmermans, H. (2015). CFD simulation and validation of urban
microclimate: A case study for Bergpolder Zuid, Rotterdam. Building And
Environment, 83, 79. doi:10.1016/j.buildenv.2014.08.004
[4] United States Environmental Protection Agency. (2015, September 22). Heat Island
Effect. Retrieved from: http://www2.epa.gov/heat-islands.
[5] Corumluoglu, O., & Asri, I. (2015). The effect of urban heat island on Izmir's city
ecosystem and climate. Environmental Science And Pollution Research, 22(5), 3202
3211. doi:10.1007/s11356-014-2874-z
[6] National Research Council. (2009). Driving and the built environment: The effects of
compact development on motorized travel, energy use, and CO emissions.
Washington, D.C., Transportation Research Board.
2
[7] Seto, K., Fragkias, M., Güneralp, B., & Rielly, M. (2011). A meta-analysis of global urban
land expansion. PLoS ONE, 6(8): e23777. doi:10.1371/journal.pone.0023777
[8] Douglas, I. (2012). Urban ecology and urban ecosystems: Understanding the links to
human health and well-being. Current Opinion In Environmental Sustainability, 4,
385-392. doi:10.1016/j.cosust.2012.07.005
[9] Fouillet, A., Rey, G., Laurent, F., Pavillon, G., Bellec, S., Guihenneuc-Jouyaux, C.,
Clavel, J. & Hemon, D. (2006). Excess mortality related to the August 2003 heat wave
in France. International Archives Of Occupational And Environmental Health, 80(1),
16-24. doi:10.1007/s00420-006-0089-4
[10] Stewart, I.D. (2010). A systematic review and scientific critique of methodology in
modern urban heat island literature. International Journal of Climatology, 31, 200-217.
doi:10.1002/joc.2141
Bioremediation of Copper by Vallisneria
americana and Pontederia cordata
Sydney Jimenez
ABSTRACT Continuous fertilizer and pesticide applications have deleterious effects on Florida’s water
systems by causing excess nutrient build up. This build up can contribute to algal blooms requiring the use of
algaecides that commonly contain copper sulfate, leading to a slow buildup of copper in the water system. These
excess nutrients and heavy metals in the water kill most aquatic life. However, the use of aquatic vegetation has
been shown to be effective in the bioremediation of copper and excess nutrients in water systems (Vajpayee et al.,
2001).
Tape grass (Vallisneria Americana), a submerged aquatic plant, and Pickerelweed (Pontederia cordata),
an emergent aquatic plant, were tested for their effectiveness in the bioremediation of copper in 8 tubs simulating
UCFs storm water ponds. The tubs were tested once a week for copper concentrations in the water and suspended
soil.. It was expected that the combination of V. americana and P. cordata would collectively be the most effective
option in the bioremediation of copper in UCFs storm water ponds, However, V. americana showed an ability to
bioremediate copper far better than any other combination that was tested. Cleaning up Florida’s water systems is
important for the ecosystems that they support and the ecosystem services that they provide. Eliminating excess
nutrients and heavy metals from these systems can decrease algal blooms and allow for the repopulation of other
aquatic vegetation and aquatic organisms.
INTRODUCTION
Fertilizers and pesticides have been
applied to plants in both agricultural and
urban landscapes across the world for
centuries (Stoate et al., 2001; Bakker et al.,
2013; Turner & Rabalais, 2003) Fertilizer
treatments give plants added nutrients
needed to thrive, allowing them to grow
faster, or look better than they might without
the treatments. Pesticide treatments aid in
keeping diseases or levels of unwanted plant
growth at bay (Feder, 1979). Studies have
shown that constant applications of
fertilizers and pesticides have deleterious
effects on waterways and water bodies
where a substantial excess of nutrients, such
as nitrogen and phosphorus, are running off
into these systems from agricultural and
urban areas (Penuelas et al., 2013).
Excessive nutrient loads in water bodies are
commonly evidenced by excessive plant and
algal growth in the water body. The
resulting plant and algal blooms can alter
important ecosystem services provided by
these water systems (Smith, 2003).
Algaecide applications directly into water
bodies have become a common practice,
particularly in treating urban storm water
systems.
One of the most commonly used
algaecides, which is also most commonly
applied to storm water systems and ponds, is
copper sulfate (Zhou et al., 2013; Boyd &
Massaut, 1999). Algaecide applications
containing copper sulfate are potentially
harmful because there is a small window of
safety in terms of levels of copper based
algaecides that will be able to rid freshwater
systems of algal blooms while not seriously
affecting any non-target species (MurrayGulde et al., 2002). However, with dense
algal blooms that requires higher
concentrations of copper based algaecides to
be destroyed, the copper thresholds of nontarget species in the surrounding water
system is easily reached or exceeded
(Murray-Gulde et al., 2002). When
nutrients, such as nitrogen and phosphorus,
and heavy metals, such as copper, build up
in water bodies to harmful or toxic levels,
oxygen deficient, or hypoxic, conditions
result. These conditions can lead to
hypereutrophication of water bodies, killing
plant and animal life from excess toxins and
lack of oxygen (Briand et al., 2003).
Applications of these chemicals
directly into freshwater bodies pose a great
threat to the health of these systems by
causing extreme nutrient loads and toxic
build up that will damage aquatic organisms
and degrade the aquatic ecosystem
(Dudgeon et al., 2006). Copper sulfate is a
compound that is applied directly to
freshwater bodies as an algaecide, which are
chemicals designed for killing or preventing
algal growth. Algaecides are important in
hypereutrophic freshwaters that have
become overrun by excessive algal growth
and cyanobacteria, which can be detrimental
to the sustainability of these aquatic
ecosystems. However, once an algaecide has
been applied, the chemistry of the water is
altered and, after spreading through the
water and killing off any algae it comes into
contact with, any excess that has not been
well diluted, because copper sulfate is
denser than water, will accumulate as
sediment on the pond bottom (Watson &
Yanong, 2011; Zhou et al., 2013). After
collecting in soils, excess copper has the
ability to kill aquatic plant life, bottom
dwelling organisms such as mussels, and
fish because “aquatic animals are exposed to
copper by more than just dietary routes”,
such as through soils or water, and are
therefore “more sensitive to copper than
terrestrial animals” (EPA, 2006). When
these organisms die and begin to decay, they
add phosphorous and ammonia, which
eventually becomes nitrates, to the water as
wastes, altering the water quality and
creating the perfect environment for algae to
thrive which adds to the decline of
macrophytes (Lacoul & Freedman, 2006).
Florida in particular suffers a great
deal from excess nutrients and pollutants in
its water systems (Graves et al., 2004).
Pesticides and heavy metals that are toxic to
aquatic fauna have been repeatedly found in
Florida’s water systems at unsafe levels
(Graves et al., 2004). This is particularly
dangerous in storm water ponds and canals
where the excesses of these pollutants get
washed into. Copper in particular is one
heavy metal that has frequently been found
to be in excess in Florida’s water systems
where it is applied as an algaecide or is
runoff from a nonpoint source (Graves et al.,
2004). This is a call for concern because of
the toxicity related to excess copper levels
and its subsequent effects on aquatic life.
In rare occasions, applying copper
compounds to water systems is not
necessarily a detriment. The bioavailability
of copper is an important factor to take into
account. Copper is a naturally occurring
metal in water systems and is an essential
element for all plants and animals at low
levels (EPA, 2007). Therefore, adding
copper compounds to freshwater systems
may prove to be advantageous if the current
conditions of the particular water system are
lacking in this element. Yet, because most
aquatic organisms only require trace
amounts of copper in their systems in order
to survive, any excess that is unable to be
controlled by their “homeostatic control
mechanisms” proves to be detrimental (Pena
& Pocsidio, 2007). If the case is that there
are already adequate amounts of copper in a
water system, then adding an excess of this
element to water has proven to be a risk to
the health of plant and animal life (EPA,
2006). Therefore, the toxicity and amount of
harm that introducing copper to water
systems can have on aquatic life is almost
completely dependent upon the current
bioavailability of copper currently in the
system (EPA, 2006).
A worst case scenario for the
collection of pollutants in water systems is
hypereutrophication. Hypereutrophication is
when nutrients and pollutants collect in
excess in water systems, stimulating the
growth of algae to uncontrollable levels, and
causing the death of all plant and animal life
from hypoxia, a lack of oxygen in the water.
Excess nutrients such as phosphorous and
nitrates, that result from detritus or fertilizer
and pesticide run off, are typically catalysts
in altering water quality (Camargo &
Alonso, 2006). Once these levels become
undesirable and stimulate the growth of
algae blooms, dissolved oxygen has been
shown to decrease, creating hypoxic
conditions that choke the life out of aquatic
fauna (Camargo & Alonso, 2006). Algae
blooms are also responsible for aquatic plant
deaths because of their ability to form
floating mats that block sunlight from
reaching submerged plant life. Poor water
quality also alters the water pH, which is
responsible for determining the solubility of
nutrients or other elements in the water. A
low pH (around 5 or lower) allows heavy
metals to dissolve in water (Perlman, 2013)
which is an important factor to take into
account when considering copper levels in
water. Managing the alkalinity of water
systems and how well water is able to offset
acids is an important consideration when
dealing with copper concentrations in water.
Low alkalinity levels pose a threat to aquatic
life because it allows for a low pH, which
increases the toxicity of copper in the water,
since heavy metals become more soluble
(Watson & Yanong, 2011). A low pH would
require a higher alkalinity to neutralize the
acidity of the water.
Lake Apopka is an example of a
hypereutrophic lake in the Central Florida
area. As a result of wastewater runoff from
surrounding farmlands, the lake has been
overrun with nutrients, resulting in dense
cyanobacteria and algal blooms. This has
hindered the growth of aquatic vegetation in
the lake, particularly submersed
macrophytes (Coveney, et al., 2002). A
restoration plan was put into effect for Lake
Apopka that involved a constructed
treatment wetland to assist in the removal of
excess nutrients from wastewater and runoff
as it filters through and makes its way
towards the lake (St. Johns River Water
Management District, 2014). Using
wetlands, and other natural systems, to
relieve environments from excess nutrients
that cause polluted waters has become a
practice that is occurring more and more
readily because they “provide a combination
of physical, chemical, and biological
processes that contribute to the removal or
transformation of pollutants (Davies &
Bavor, 2000).
When dealing with excess nutrients
and pollutants in water systems, the
bioremediation of these systems
(introducing naturally occurring elements or
organisms to uptake and control levels of
toxins) becomes an increasingly important
topic of concern. Bioremediation can occur
through plants or animals that are able to
uptake the excess of these materials in the
water, given proper conditions. For example,
many species of aquatic vegetation “have
shown tremendous capacity to reduce the
level of toxic metals, nutrients, biological
oxygen demand, and total suspended solids
from polluted waters” (Vajpayee et al.,
2001). Submerged aquatic vegetation and
emergent aquatic vegetation in particular are
essential tools in water purification. As
mentioned with Lake Apopka, natural
systems have shown to be useful in the
bioremediation and restoration of Florida’s
water systems (Coveney et al., 2002) by
filtering out the excesses of these pollutants
that can be found in the water and in the
sediment.
Tape grass (Vallisneria americana)
is one species of submerged aquatic
vegetation that is native to Florida and has
been shown to absorb metals and pollution
from soils and polluted waters (Vajpayee et
al., 2001). Emergent aquatic vegetation has
also been shown to provide an ecosystem
service in this sense that they are able to
absorb excesses of nutrients and pollutants
that cause toxicity in the water. In
particular, Pickerelweed (Pontederia
cordata) is another aquatic plant native to
Florida that has shown to be effective in
improving water quality and in the uptake of
excess nutrients (Lu et al., 2014).
Tape grass (Vallisneria americana),
also known as Florida Eel grass or Wild
Celery, is a submerged aquatic plant native
to Florida. Submerged vegetation is an
important aspect of aquatic systems because
they provide food and a safe place to hide
for aquatic organisms. V. americana in
particular grows into dense underwater
forests, forming the ideal hiding place for
aquatic life. V. americana is also a food
source for waterfowl and many aquatic
species (Mazzotti et al., 2011). Predation
and consumption of V. americana is also
helpful regarding seed dispersal because of
the improved germination that results
(Lodge, 1991). V. americana has also been
shown to be helpful in managing and
maintaining nutrients in the water and soil,
thereby providing an improved water
quality, while also aiding in sediment
stability (Mazzotti et al., 2011). Aquatic
grasses and other vegetation are showing
increasing importance with regard to
determining the health and quality of life in
aquatic environments (Bortone & Turpin,
2000), making V. americana a useful aspect
of aquatic ecosystems, both for
bioremediation of nutrients and pollutants
found in water systems, as well as a resource
for aquatic organisms to thrive on. Aquatic
grasses and other aquatic vegetation are an
essential resource for aquatic organisms and
many terrestrial species as well.
Pickerelweed (Pontederia cordata)
is an emergent aquatic plant, growing in
shallow waters, usually along the shoreline
of ponds, lakes, or rivers. It has been shown
to be an adequate food source for water fowl
as well as providing shelter and cover for
bird and fish populations (Rodgers & FWC).
Due to wastewater and excess nutrients and
pollutants entering Florida’s water systems,
aquatic and wetland plants such as these
have proved to be imperative in the recovery
of these aquatic systems because of their
ability to both absorb pollutants into their
tissues, and to act as water purifiers (Sun et
al., 2013). P. cordata has been shown to be
helpful in the uptake of excess nutrients as
well as heavy metals in water systems
through the soil (Collins et al., 2005). This
plant is also particularly favored for pond
environments where still waters allow it to
uptake excess nutrients and pollutants more
effectively (Han et al., 2013).
The use of aquatic vegetation as
bioremediators can be an effective method
of reducing the excess levels of nutrients
and heavy metals that reach dangerously
high levels and pose a threat to aquatic
systems in the process. These methods could
be used in the storm water ponds at the
University of Central Florida to decrease the
levels of pollutants and toxins that degrade
these systems. Creating healthier water
systems is essential because every living
organism relies on their wellbeing, making
them a critical component of terrestrial food
webs (as well as aquatic foods webs).
Although this is complicated by the fact that
water bodies are typically on the receiving
end of pollution (Dudgeon et al., 2006). The
biodiversity of these areas is dependent upon
and reflective of the conditions of aquatic
ecosystems. An impact on once aspect of an
ecosystem has a domino effect on all other
aspects that it is either directly or indirectly
connected to. However, because of the
sensitivity of these systems, pollution has
put aquatic species in more danger than
terrestrial species, with more aquatic life
being threatened or extinct compared to
terrestrial (Richter et al., 1996). The algae
growth that results from these excesses of
pollutants is detrimental to aquatic life, but
could be taken care of by introducing
aquatic macrophytes as a restoration
technique because of their ability to “inhibit
algae growth through nutrient deprivation”
(Han et al., 2013). Taking action to decrease
pollutants and toxins in ponds would be
beneficial to both aquatic and terrestrial life.
Therefore, introducing V. americana and P.
cordata to UCF’s storm water ponds as
bioremediators to clean up pollutants and
reduce algae levels should prove to be
advantageous to these ecosystems.
HYPOTHESIS
Given that aquatic vegetation has
proven to aid in the bioremediation of
polluted water bodies, it is expected that the
use of both V. americana and P. cordata
together will be the most effective in the
bioremediation of toxins and the managing
of nutrient cycles in pond systems to prevent
severe algae growth.
and the P. cordata were collected from
another one of UCFs storm water ponds,
also 37 days after a copper sulfate
application. These tubs were placed in an
indoor setting with a single 48” T8 HO
fluorescent bulb. Air pumps were also
placed in each tub in the middle of the first
week, after the first copper tests had been
completed, to allow for better circulation of
water in the tubs.
Two of the tubs were a control,
holding water and soil only. The next two
tubs contained only V. americana, the next
two only P. cordata, and the final two tubs
contained both V. americana and P. cordata.
The first week of testing began on the week
after the water, soil, and plants had been
collected and situated into their appropriate
tubs.
Each tub was tested for free copper,
total copper, nitrate, phosphorous, and pH.
Dissolved oxygen tests were left out because
of the possibility of these tests being skewed
from the use of the air pumps. The water in
the tubs was tested once a week on
MATERIALS AND METHODS
The effectiveness of bioremediation
of copper in water systems using V.
americana and P. cordata was carried out
using 8 tubs, capable of holding 10 gallons
of water each. Water and soil was obtained
from a storm water pond on the UCF
campus approximately 35 days after a
copper sulfate application. Two inches of
soil and seven inches of water were placed
in each tub. The V. americana were
collected from Lake Claire approximately
37 days after a copper sulfate application
Set‐up of the 8 tubs
Wednesdays for five weeks. The copper
tests were completed using the YSI
photometer and the pH, phosphorus and
nitrate tests were completed using an urban
water test kit. The first test day was during
the week following the collection of the
plants, water and soil to allow for a small bit
of time for the plants to become rooted in
the substrate and accustomed to the water
and soil conditions. Water visibility was also
tested in each tub by placing a ruler into the
water until the bottom of the ruler was
unable to be seen. Visibility was recorded
starting with the second week.
Tests to determine the levels of
copper in the soil would have been
performed if the experiment had been
carried out with larger sample sizes. Given
that each bin held only two inches of soil,
soil tests were unable to be completed
because removing the soil for the tests
would have left insufficient soil amounts for
the plants to be rooted in for the remainder
of the experimentation period.
RESULTS
At the time of the first tests, the
plants had already been in the tubs for six
days.
The YSI photometer that was used
was able to read copper concentrations
between 0-5mg/L. The results of the copper
tests can be seen in figures 4 and 5. From
the five week experimentation period,
copper concentrations decreased most in the
tub containing only V. Americana, The
second best at decreasing copper
concentrations in aquatic systems was the
tub containing P. cordata alone. The next
best was the tub containing both
Figures 1‐3: pH, nitrate & Phosphorus levels for the 5 week experimentation period. macrophytes. The control tub contained
copper concentrations above what the YSI
could read (> 5mg/L) for the entire
experimentation period, with the exception
of the first week, which could be attributed
to the fact that the water pumps had not yet
been put in place and so the water in the tubs
was not mixed uniformly, and so the
majority of the copper may have sunk to the
bottom of the tub.
These results are not in favour of the
original hypothesis that both of these
macrophytes would be better at
bioremediating when used in conjunction
with each other. Rather, both were better off
used separately.
pH, nitrate, and phosphorous tests
were also completed once a week, the results
of which can be seen in figures 1-3. These
tests were completed using an urban water
test kit. The results of these tests were
difficult to interpret in the first couple weeks
of testing because of the poor visibility of
the majority of the tubs which made the
colour of the tests difficult to read.
Each week, before testing, the air
pumps in each tub were cleaned and any
detritus stuck in them was removed to allow
for proper water circulation throughout the
entire experimentation period. Afterwards,
visibility (figure 6) in each tub was recorded
in inches with a ruler to determine how deep
someone could see into each tub.
DISCUSSION
Heavy metals in aquatic systems are
able to easily bond with organic and
inorganic materials or sediments such as
clay and sand. When heavy metals,
including copper, become chelated with
another compound, they become incredibly
dense and sink to the bottom where they
settle in with the sediment. However,
“turbulence can resuspend the sediments
making (under favourable conditions) the
elements available to macrophytes”
(Guilizzoni, 1991). Since soil tests were
unable to be completed within this
experiment in order to determine copper
levels in the soil, this concept was put in
place using the water pumps to circulate the
water in the tubs and prevent the top layers
of sediment from completely settling and
allow for a more accurate reading of the
amount of copper that is actually present in
these systems. Seeing as the majority of
copper in aquatic systems is found settled in
the sediment, this could have accounted for
many of the high levels of copper that were
recorded as being above the YSI
photometer’s limits throughout the
experimentation period.
In aquatic systems, decreasing pH
values equate to an increase in the solubility
of heavy metals in the water. As already
stated, when pH values get too low this can
become dangerous because it allows heavy
metals to become more soluble and therefore
have the potential to cause copper
poisoning, killing aquatic organisms and
plants. However, in order for plants to be
used as bioremediators of copper, heavy
metals must be soluble enough to be taken
up by these plants while also not being too
soluble so as to cause severe damage to the
ecosystem. Throughout the experimentation
period, the tubs that had decreased pH
values showed greater signs of copper
uptake. Even when pH values were shown to
be increasing, a correlation was still seen
regarding the copper concentrations. For
example, a steep increase in pH was seen
alongside a more gradual decrease of copper
concentrations whereas a more shallow
increase of pH correlated to a greater
increase in the uptake of copper, and a
decrease in the pH was correlated to the
highest uptake of copper in the tubs.
However, the pH in all of the tubs never
approached a dangerously low pH level,
which would allow a dangerous amount of
heavy metals to become soluble and
available to organisms. The pH typically
stayed within the normal pH range for
aquatic systems (around 6-8).
Naturally occurring levels of copper
in freshwater systems range from .0002-.03
mg/L (EPA, 2007). Only the tub containing
V. Americana eventually fell within this
natural range. By the end of the
experimentation period, all other tubs still
had copper concentrations significantly
above even the highest acceptable and
natural levels of copper in aquatic systems.
This is a cause for concern, because this
much copper in the storm water ponds at
UCF can be hazardous to aquatic and
terrestrial life because of the risk of inducing
copper poisoning if too much is ingested or
absorbed. However, because aquatic systems
do not exist alone and are connected to their
surrounding ecosystems, the toxicity of
copper, and risks of copper poisoning, in
aquatic systems has subsequent effects in
terrestrial systems as well. Any aquatic or
terrestrial organisms that may consume
other organisms carrying high heavy metal
loads risk heavy metal poisoning
themselves. When copper accumulates in
aquatic organisms that are consumed by
terrestrial organisms, the copper gets
transferred and begins to accumulate in
terrestrial organisms. For example, the
Florida Snail Kite feeds on mainly Florida
Apple Snails that have shown an incredible
ability to accumulate copper (Hoang et al.,
2008). When snails and other aquatic
organisms accumulate copper and heavy
metals in their systems, they are transferred
to predators when eaten, such as the
endangered Florida Snail Kite, which is
believed to pose a great threat to their
health, and especially the health of these
birds (Frakes et al., 2008).
The use of macrophytes as
bioremediators is effective because of their
ability to remove excess heavy metals from
the surrounding environment and distribute
and accumulate them throughout their roots
and tissues (Guilizzoni, 1991). The
significant ability of V. americana to reduce
copper concentrations in aquatic systems
could be due to the fact that the entire
biomass of the plant is under the surface of
the water. Vallisneria species have been
shown to collect copper in their roots, then
their leaves, and then their rhizomes
(Vajpayee et al., 2005). V. americana also
has a shallow root system close to the
surface sediment layers where most copper
that settles is present, and therefore, more
copper is accessible to it for uptake. On the
other hand, P. cordata has a deeper settled
root system with large rhizomes. This is
another cause for P. cordata’s decreased
copper uptake when compared to V.
americana that has a “higher root absorption
due to the greater exposure to concentrated
elements at the sediment-water interface
than do plants rooted more deeply” (Collins
et al., 2005; Mudroch & Capobianco,
1978).
Despite being a necessary element
for all organisms, the toxicity of copper has
shown to be dependent upon the
concentrations of copper in the water and
the sensitivity of the organism in question
(Cyrino de Oliveira-Filho et al., 2004).
Depending upon how readily an organism
may absorb copper from their surroundings
or how much they are able to accumulate in
their bodies before it causes harm are both
factors to be accounted for in determining
how lethal excess copper in a given system
may be to any particular organism. Because
copper sulfate is an algaecide meant to
inhibit the spread of harmful algal blooms or
for controlling excess algae or plant growth,
it has shown to have similar effects on all
other surrounding organisms. For example,
continuous absorption of excess heavy
metals by macrophytes has shown to be
deleterious to their health and inhibits their
growth and function (Guilizzoni, 1991). It
was not until about the final week during the
experimentation period that the P. cordata
began to show signs of poor health such as
the stalks to the plant becoming weak and
flimsy. The leaves of P. cordata also began
to wilt much quicker as the experiment
carried on beginning with the third week. On
the other hand, the only signs that the V.
americana showed of decreased health was
the occasional wilted leaf and, on the whole,
appeared to be in rather good health
throughout the entire experiment. Given
these findings, it is probable that the V.
americana had a higher tolerance for
absorbing and holding copper than did the P.
cordata, which would make it a more
successful candidate in the bioremediation
of aquatic systems that are exposed to high
copper loads. Aside from the effects on
macrophytes, excess copper in aquatic
systems has also shown to inhibit the growth
of freshwater fish (Cyrino de Oliveira-Filho
et al., 2004) thereby creating unhealthy
populations that may be unable to perform
their jobs in maintaining the ecosystem.
Copper sulfate has also been shown
to be a detriment to human life. Copper
sulfate in particular has proved to be capable
of severe irritation, including irritation to the
respiratory system from inhalation of dusts
or mists, which has shown the possibility of
becoming cancerous if inhaled chronically
(EPA, 2006). However, unlike with aquatic
organisms, copper has a much more limited
solubility in human systems, which adds to
its low systemic toxicity in humans (EPA,
2006).
The bioremediation of these systems
is imperative in order to avoid possible
devastation in the future. Although, with
normal or high pH levels, copper stays
mostly either insoluble or chelated with
other substances in the water and therefore
mainly inert in the pond bottoms and only
infecting whatever may be able to absorb it.
However, heavy metals still remain a threat
because of the future possibilities of
wreaking havoc on an ecosystem when
given adequate conditions.
The environments that surround us
are dependent upon the connections that
they have to their own surrounding
environments. It is impossible to have an
effect on one environment without it
creating a domino effect and disturbing
other environments. When we add excesses
of pollutants into Florida’s water systems, it
opens the possibility for them to “adversely
affect the structure and function of biotic
communities” (Graves et al., 2004). When
pesticides and fertilizers are used in
agriculture and landscaping, it ends up
running off into our water systems. Here it
creates an excess of nutrients in the water,
creating the perfect habitat for algal growth.
These algae blooms, which end up killing
aquatic life, are what spawn the needs to use
algaecides, such as copper sulfate, in an
attempt to return these habitats to a more
pristine condition. However, given the right
preemptive conditions, such as maintaining
aquatic vegetation populations to control
excess nutrient loads and using snails, and
other mollusks, to aid in the uptake of
excess nutrients and toxins from the water,
the restoration of our water systems is
achievable. The use of wetlands in particular
has shown great capacity to reduce nutrient
loads in water systems that have reached
hypereutrophic levels (Graves et al., 2004;
Davies & Bavor, 2000; Knight et al., 2000;
Coveney et al., 2002).
OTHER OBSERVATIONS
Figure 6: Water visibility for the 5 weeks, measured with a rule in the top layers of the water. Copper concentrations also appeared
to occur in sync with the visibility of the
water. As the water visibility increased in
the tubs (see figure 6), a decrease was seen
in the free and total copper concentrations in
the water. However, this could have also
been attributed to the filtering ability of the
individual plant species and their ability to
hold the sediment in place if it settled,
preventing it from being suspended again.
With V. americana’s shallow roots, it is
possible that it was able to better hold
surface sediment in place. If this was the
case, any sediment finally being able to
settle in the tubs along with any chelated
copper, would make any tests performed
afterwards account only for the copper that
was still left suspended or free.
Water levels began to show slight
decreases from evaporation during the
second week and slowly increased. By the
end of the experimentation period, water
levels in all tubs were approximately 5” with
approximately 2” lost in total. The only
exceptions were the tubs containing only P.
cordata, which lost approximately 2.5” of
water. It is possible that the
evapotranspiration that emergent
macrophytes undergo played a role in the
greater water loss by P cordata.
When testing for free and total
copper, more often than not the total copper
concentrations were displayed as lower than
the free copper concentrations which seems
impossible considering that total copper is
equal to the free copper plus any chelated
copper in the system. Soil tests were meant
to be completed so that copper decreases
could be better monitored more closely
seeing as much of the copper in these
systems sinks and mixes with substrates.
However, because of the size of the tubs and
the amount of substrate that was used, soil
testing was not an option because there was
not enough soil to spare for testing.
CONCLUSION
Aquatic systems are put in harm’s
way through excess runoff that has the
ability to create hypereutrophic conditions,
negatively impacting the function of these
habitats and the ecosystem services that they
provide. The use of macrophytes as
bioremediators is an essential asset in the
restoration of systems that have been
damaged by overloads of nutrients or heavy
metals. Submerged aquatic vegetation in
particular has proved to be an invaluable
asset in decreasing harmful loads of heavy
metals in aquatic systems. It is important to
decrease heavy metal loads in aquatic
systems before conditions alter to allow
them to pose an even greater threat to the
health and safety of every organism that
lives in, and relies on them.
However, with continued algaecide
applications, there is only so much that
macrophytes can do for aquatic systems in
terms of restoration until they succumb to
the toxicity of copper from high absorption
rates.
ACKNOWLEDGEMENTS
Thanks to Jennifer Elliott and Alaina
Bernard for their guidance and support and a
very special thanks to the Arboretum for
allowing me to use their facilities during the
5 week experimentation period. Another
very special thanks to Jacqueline Gibson for
assisting in the collection of water, soil and
plant specimens.
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1
Assessment of sustainability awareness and attitudes among college undergraduates
Edgar Castro Tello, Amanda Faunce, Kristen Garcia, Catalina McEachern, and Cody Sparaco
ABSTRACT
Sustainability encompasses three pillars: environment, economy, and social equity. This study explored
the correlation between undergraduate students of different academic Colleges at the University of
Central Florida, and their understanding of the term “sustainability” based on the three pillars. To
determine if a correlation exists, 435 students completed surveys, with the goal of surveying 40 students
per academic College. The survey was composed of one open-ended question about the meaning of
sustainability, 15 statements based on the Likert scale measuring sustainability attitude, and three
demographic questions. Once the data was collected, the open-ended results were scored based on the
number of pillars mentioned and the Likert statements were scored on a 1-5 scale. The statistical tests
revealed significant values for both the pillar and sustainability attitude scores when calculated along
with academic College. Therefore, the study concluded that there is a correlation between academic
College, and knowledge and attitudes of sustainability.
INTRODUCTION
Even with current problems such as climate change, habitat destruction, and water pollution,
environmental issues are yet to be at the forefront of citizen concern. In 1978, Dunlap and Van Liere
found a surprisingly high percentage of people who were leaning towards the New Environmental
Paradigm, now renamed New Ecological Paradigm (NEP). Unfortunately, 36 years later, national
environmental concern is strongly lacking. In fact, concern for the environment is typically ranked as
one of the lowest on a list of other social issues in the United States (Riffkin, 2014).
This poses a serious problem because the beliefs of the public play a large role in government
policy (Robelia and Murphy, 2011). In part due to climate change, as well as the need for government
funding towards other ecological remedies, our environmental issues have also become social and
economic issues (Burns, 2013). Without support from the public towards better policy, environmental
issues will not be addressed nor resolved.
2
A strong force to solve our social, economic, and environmental issues and gain support from the
public is to focus on sustainability. Sustainability is not solely an environmental issue, as it is typically
portrayed, but instead it is multifaceted and involves other components of study (Opp & Saunders,
2013). Sustainability helps with solving environmental and societal concerns since it incorporates
different disciplines and fields of study to come to a true and lasting solution. Attention towards
sustainability will help society utilize our resources in a manner that will not compromise future
generations (Hansmann et al, 2012).
Due to its interdisciplinary nature, sustainability is difficult to define (Michelsen, 2013). In fact,
the biggest challenge for sustainability education is simply defining sustainability (McFarlane and
Ogazon, 2011). One approach in defining sustainability is the tripartite or pillar model. This model
consists of the three disciplines, the environment, economy, and social equity; a balance between these
three pillars is important (Opp & Saunders, 2013).
The purpose of this research study was to observe the relationship between a student’s
understanding of sustainability and his or her education. To accomplish this purpose we sought to see if
two different correlations exist among University of Central Florida (UCF) undergraduate students:

First, between students’ academic College and the extent to which they understand the term
“sustainability.”

Second, between the same academic Colleges and the students’ sustainability attitudes.
The study focused on undergraduate students at UCF because they represent the future workforce, and
thus future policy influences. Focusing on undergraduate students is also important since secondary
education is the most influential in shaping worldviews (Burns, 2013). Also, the significance of
sustainability is increasing as time passes (Beringer, 2007). With the notion that a student’s academic
College would affect their answers, we expected to see a correlation between academic Colleges and
sustainability comprehension and attitude.
METHODS
To determine if there is a correlation between undergraduate students’ academic College and their
knowledge of sustainability and sustainability attitude, a survey was administered on campus. This
survey was distributed to 435 undergraduate students, a representative sample size of the undergraduate
population at UCF. With a total of 51,298 students, a 400 sample size provides a 95% confidence level
with a 5% margin of error. The students surveyed represent ten academic Colleges within the University
3
of Central Florida including: Arts and Humanities, Business Administration, Education and Human
Performance, Engineering and Computer Science, Health and Public Affairs, Rosen Hospitality
Management, Nursing, Medicine, Sciences, and Undergraduate/Interdisciplinary Studies. The sample
size was divided among the 10 Colleges, yielding around 40 surveys per College. However, surveys
from the College of Nursing and Rosen did not reach 40.
The survey was divided into three specific sections. The first was an open-ended question where
a student could provide an unreserved answer to explain what sustainability means to them. This
question was used to see if the students incorporated the three pillars into their personal meaning. The
second part of the survey was designed using the Likert scale method in which a “Strongly Agree” to
“Strongly Disagree” spectrum of answers was provided for participants. This part measured
sustainability attitude and consisted of 15 questions total. There were five questions concentrated from
each of the three pillars of sustainability, shown in Table 1. Most questions were created specifically for
this survey but some came from previous studies. Questions 1, 2, and 7 are from Rideout (2013) and
number 15 is from Dunlap and Van Liere (1978). In most cases, choosing a “Strongly Agree” answer
was considered a higher level of sustainability awareness but for some questions (1, 3, 8, 11, and 14)
choosing a “Strongly Disagree” answer was more sustainable. This reversal was done to insure that the
students were actually reading the statements. However, in the analysis process, the inverted questions
were switched to mirror the regular ones on a 1 to 5 scale. The last section of the survey collected
demographic information including academic College, class standing, and biological sex in a multiplechoice response. The survey was administered both online and on paper.
The online version of the survey inhibited students from going back and changing answers to
previous questions. In this way, the answer to their interpretation of the term “sustainability” was not
altered by subsequent questions inferring about environmental behaviors.
After the data was collected, the information was processed in multiple approaches. To start, the
open-ended responses were categorized on a scale of 0-3 based on the amount of pillars the student had
incorporated into their response. These scores were then analyzed using a chi-square test and a one-way
ANOVA along with academic College. The Likert statements were organized into a 1-5 scale with a
score of 1 representing a “Strongly Disagree” answer and 5 representing a “Strongly Agree”. As stated
above, the inverted questions were switched to match the others, where a 5 showed a strong
sustainability attitude. Theses scores were also analyzed using a one-way ANOVA with academic
College.
4
Table 1: Sustainability Attitudes Survey
Below are the 15 Likert questions administered to UCF undergraduate students from each of the academic Colleges. Note
that in order to determine a student’s sustainability attitude, the survey consisted of questions based on the three pillar
categories: environment, economy, and social equity. Each question is based on a Strongly Disagree to Strongly Agree scale.
The percentages show the overall response rate for all 10 Colleges.
1. Humans have the right to modify
the natural environment to suit their
needs.
2. The earth is like a spaceship with
very limited room and resources.
3. All Americans have access to
clean water and air.
4. All urban development planning
should incorporate environmental
aspects.
5. Climate change is having a
global effect on the environment.
6. I will generally choose the
cheaper product regardless of its
environmental impact.
7. Humans are severely abusing the
environment.
8. Economic development is more
important than environmental
conservation
9. Corporations should take
preventative measures when
addressing their environmental
impact, even when it hinders
economic production.
10. Humans are one of the main
contributors to climate change.
11. Investing in renewable
resources will not make a
difference in environmental quality.
12. We should create vast wildlife
preserves with restricted human
access.
13. It is important to think of future
generations when making economic
decisions today.
14. My environmental actions and
choices will not make a difference.
15. Humans must live in harmony
with nature in order to survive.
Strongly
Disagree
Disagree
Unsure
Agree
6.62%
Strongly Agree
28.31%
19.63%
36.07%
9.36%
5.71%
9.82%
5.48%
40.87%
38.13%
27.63%
45.66%
9.59%
11.64%
5.48%
1.14%
1.83%
6.85%
36.07%
54.11%
1.83%
3.88%
10.27%
35.39%
48.63%
8.68%
29.22%
20.32%
34.02%
7.76%
2.05%
4.34%
10.27%
42.92%
40.41%
26.03%
47.26%
19.63%
5.71%
1.37%
1.37%
3.42%
9.59%
46.80%
38.81%
0.91%
6.16%
14.61%
38.36%
39.95%
35.62%
43.61%
11.42%
5.94%
3.42%
1.83%
5.71%
18.49%
42.47%
31.51%
1.14%
1.14%
2.28%
33.33%
62.10%
34.70%
46.58%
9.13%
7.99%
1.60%
1.60%
3.42%
7.99%
45.89%
41.10%
5
RESULTS
To determine if a correlation existed between pillar scores and academic Colleges, the data was analyzed
through a chi-square test shown in Figure 1. Upon analyzing the data, the chi-square test indicated a
0.0346 significant p-value for pillar scores.
The pillar scores were also processed in a one-way
ANOVA, which yielded a 0.0001 significant p-value. Both of these scores show a significant correlation
between the pillar score and academic College.
3
2
0.75
1
0.5
0.25
UN/IDS
SCI
ROSEN
NURS
MED
HPA
ENG
ED
0
BA
0
ARTS
Response Probablity of Pillar Score
1
Academic College
Figure 1: Distribution of Pillar Scores Per College. Color represents how many pillars mentioned. Width represents number
of responses. Height shows response probability with the entire sample equaling 1. The right side column shows the
proportions for all Colleges combined.
The sustainability attitude answers were also analyzed through a one-way ANOVA shown in
Figure 2. The ANOVA test indicated a 0.001 significant p-value for Likert scores. This shows that there
is a correlation between sustainability attitude and academic College.
6
5
4.5
Likert Score
4
3.5
3
2.5
2
UN/IDS
SCI
ROSEN
NURS
MED
HPA
ENG
ED
BA
ARTS
1.5
Academic College
Figure 2: Distribution of Sustainability Attitudes (Likert Scores) Per College. The middle line in the diamond represents the
College’s mean score. The height of the diamond represents confidence and the width represents number of responses.
Lastly, the proportion of each pillar category per College is visualized in Figure 3. This Figure shows
Proportion Mentioned
which pillar category each College mentioned the most and the distribution of all three.
100%
80%
60%
12
9
10
17
14
11
16
5
6
14
40%
20%
14
13
12
11
8
11
9
7
19
10
13
0%
Figure 3: Distribution of Pillar Categories Mentioned Per College.
4
24
5
15
6
32
26
21
18
environment
equity
economy
7
DISCUSSION
Our results provide supporting evidence that there was a significant correlation between each
UCF academic College and an individual's’ definition of sustainability as well as their sustainability
attitude. The variance of pillar scores and sustainability attitudes between Colleges were validated by
our chi-square and ANOVA analyses. Since both p-values are < 0.05, the relationship is significant
between Colleges and pillar scores as well as between Colleges and sustainability attitudes. This could
be a reflection of how a person’s course of study expands their mindset on sustainability in various
depths.
When compared to other sociological studies based on sustainability attitudes, we found many
similarities in our results. Dunlap & Van Liere (2008) concluded from their results that the public had
“inconsistent” attitudes towards what sustainability meant. We observed this same effect based on the
fact that individuals within different disciplines may have varied perceptions. Moreover, Rideout (2013)
pointed out that individuals’ initial stance before they begin college does affect their choice in academic
major. This could have also affected the scores we observed. We also acknowledged that a
multidisciplinary approach to education also affected scores; like Burns (2013), we noticed that the
College, Interdisciplinary Studies, which employed this approach at UCF, scored higher on pillar scores
and sustainability attitudes.
However, a possible source of misrepresentation in our survey can be found within the data
collected for the Rosen College of Hospitality Management and College of Nursing. These two colleges
did not meet their goal of 40 students each, and thus may be underrepresented. We included them in the
study since we used averages as a form of analyses. In addition, as part of the open-ended response, we
asked the respondent to provide an example that would aid in our classification of the pillars they
mentioned and some of the paper surveys distributed did not have this included. Therefore, this could
have skewed the pillar scores slightly.
Nonetheless, this study can be used to improve sustainability awareness at UCF. Significant
variance within UCF indicates that more attention should be paid to sustainable development. As more
companies and governments begin to implement sustainable strategies, it is up to recent college
graduates and professionals to bridge the gap between sustainability and personal career requirements
(Brumagim & Cann, 2012). Future research on this topic can be conducted at UCF to identify
improvements in sustainability attitudes over the years. Analyzing this progression over time could
reveal the effectiveness of academic programs that incorporate sustainability themes to solve
8
sociocultural and ecological issues (Burns 2013). Due to time restraints, and the aim of staying focused
on our original question, we decided not to use the other demographic information we collected. Thus, a
future UCF study could decipher whether biological sex or class standing also affects perceptions of
sustainability; perhaps upper level electives focus more on sustainable education thus identifying
different patterns can be possible.
As environmental issues continue to increase it is important for the upcoming generations to
learn about sustainability. The role of education is vital in understanding sustainability especially since
current college students receive very little or no exposure to the idea (McFarlane and Ogazon, 2011). As
mentioned earlier, public support is required to solve environmental issues and knowledge about these
issues is the first step. Our data suggests that academic College influences sustainability awareness and
thus, implementing sustainability education into a college curriculum may lead to balancing the
economic, social, and environmental elements of the world.
ACKNOWLEDGEMENTS
The authors wish to thank Aliana Bernard from UCF Landscape & Natural Resources and Jennifer
Elliott from the UCF Arboretum for the opportunity to conduct this research and their continual
assistance. For statistical analysis, the authors thank Molly Grace, Madison Hall, and Chris Long. The
authors would also like to thank Jacques Werleigh, John Guziejka, and Jonathan Carr from the UCF
Arboretum for providing the service learning materials and David Garcia for help with the survey
design.
WORKS CITED
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assessment against North American peers. International Journal of Sustainability in Higher
Education, 8(4), 446-461.
Brumagim, A. L., and Cann, C. W. 2012. A Framework for Teaching Social and Environmental
Sustainability to Undergraduate Business Majors. Journal of Education for Business, 87(5), 303308.
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Burns, H. 2013. Meaningful Sustainability Learning : A Study of Sustainability Pedagogy in Two
University Courses. International Journal of Teaching and Learning in Higher Education, 25(2),
166–175.
Dunlap, Riley E. and Kent D. Van Liere. Rpt 2008. "The 'New Environmental Paradigm.'" The Journal
of Environmental Education. Vol. 40. (Originally published 1978)
Hansmann, R., Mieg, Herald, and Frischknecht, Peter. 2012. Principal sustainability
components:empirical analysis of synergies between the three pillars of sustainability,
International Journal of Sustainabile Development & World Ecology. 19(5), 451-459.
McFarlane, D. A. and Ogazon A.G. 2011. “The Challenges of Sustainability Education.” Journal of
Multidisciplinary Research. Vol. 3 p.81-107.
Michelsen, G. 2013. Sustainable Development as a Challenge for Undergraduate Students: The Module
“Science Bears Responsibility” in the Leuphana Bachelor’s Programme. Science and
engineering ethics, 19(4), 1505-151
Opp, S. M., and Saunders, K. L. 2013. Pillar Talk: Local Sustainability Initiatives and Policies in the
United States--Finding Evidence of the “Three E’s”: Economic Development, Environmental
Protection, and Social Equity. Urban Affairs Review, 49(5), 678–717.
Schoolman, E. D., Guest, J. S., Bush, K. F., and Bell, A. R. (2011. How interdisciplinary is
sustainability research? Analyzing the structure of an emerging scientific field. Sustainability
Science, (1), 67.
Rideout, Bruce E. August 2013. "The liberal arts and environmental awareness: Exploring endorsement
of an environmental worldview in college students." International Journal of Environmental &
Science Education. Vol. 9
Riffkin, Rebecca. May 12, 2014. “Climate Change Not a Top Worry in the US.” Retrieved from
http://www.gallup.com/poll/167843/climate-change-not-top-worry.aspx
Robelia, B. and Murphy, T. August 23, 2011. "What do people know about key environmental issues? A
review of environmental knowledge surveys." Environmental Education Research. Vol. 18.
Stables, A. 2010. Making meaning and using natural resources: education and sustainability. Journal of
Philosophy of Education, 44(1), 137-151.
Fertilizer Filtration in Conventional Groundcovers
Ferngren, Jennifer; Cabrales, Angelica; Clark, Spencer; Maynard, Mikael; Otto, Dylan
Introduction
Expansive green lawns are a cultural norm in the US, even a requirement of many communities
across the country. In fact, lawn cover in the US surpasses the land coverage of many food crops
(Bormann 1993). In Florida, a green lawn can be maintained for most of the year, so picking an
efficient ground cover is especially important. A sustainable ground cover should have the ability
to filter out chemicals and fertilizers that are regularly applied to lawns. This is important since
these chemicals are detrimental to groundwater resources. For the purposes of this study we will
be looking at three different ground covers- St. Augustinegrass, Bahiagrass, and Zoysiagrass and
their ability to filter fertilizer and ultimately keep it out of the aquifer.
“St. Augustinegrass is the predominant vegetation used in Florida residential landscapes” (Cisar
2001). It provides a nice, bright green lawn and is fairly shade tolerant. On the down side, it
requires a substantial amount of irrigation and is not drought tolerant (Trenholm 2013).
Bahiagrass is another popular choice for lawns in Florida as it requires less watering and
fertilizer; however, it is not as popular as St. Augustinegrass due to the formation of long seed
stalks that many find unsightly and its shade intolerance (Trenholm 2013). “Zoysiagrass is a
popular warm season perennial turfgrass that tolerates stress and unfavorable conditions such as
low light, salinity, drought, and cold temperatures” (Stiglbauer 2009). Though all three of these
ground cover species have different requirements, they all require fertilization.
Introduction to Fertilizers
The main chemical found in fertilizers is nitrogen. When found in the form of nitrate (NO3-),
nitrogen is highly reactive and is prone to leaching and runoff (Raciti 2011). “Nitrogen in its
various forms has become both an essential agricultural nutrient and a major waste product of
society during the past 60 years” (Puckett 2011). “In the two decades following World War II,
fertilizer production had spiraled upward by 17 million tons, and nonfarm consumption had
become an increasingly large part of the market” (Whitney, 2010). As stated by Robertson and
Vitousek, “global nitrogen fertilizer application has increased approximately 10 fold between
1950 and 2008” (2009). This phenomenal shift in lawn care maintenance coincided hand in hand
with the rise of the green revolution. The green revolution had a significant impact on global
agricultural production,
shifting it from a localized
cultural practice to a global
industry. While the production
and use of fertilizers has
allowed society to grow more
crops and greener lawns than
the land could naturally
support, the problem is that
the excess nitrogen is moving
Figure 1 (http://www.wri.org/project/eutrophication/about/drivers)
into other natural systems. Figure 1 demonstrates the increasing use of fertilizers. “In intensive
agricultural production systems, as much as 50% of the N applied to the field is not used by the
crop plant (Cameron et al, 2013). While this paper does not discuss nitrogen pollution due to
agricultural fertilizer use, it stands to reason that much of the N being applied to lawns is not
being used by the plant.
Introduction to Aquifers
“Globally, groundwater comprises about 99% of available fresh water. As climate change
decreases the reliability of surface water systems, populations will turn more to groundwater as a
fresh water source. However, groundwater is highly vulnerable to contamination” (Puckett
2011). In Florida, the majority of our water comes from an extensive network of aquifers; the
Floridan aquifer system,
which is one of the most
productive in the US (Van
Beynen 2011) “covering
an area of 100,000 square
miles” (Miller 1990). The
Floridan is highly
vulnerable to chemical
pollution due to the
Figure 2. http://hendryutilities.com/docs/boxes/Florida_aquifers_L.jpg
surficial aquifer system which can be seen in
Figure 2 that sits close to the surface and is not confined by clay or limestone (FDEP 2007).
Figure 3 shows a map of the surficial aquifer system in the southeastern US. When fertilizer is
applied to lawns, the plants will use much of it, but the excess is subject to runoff, leaching, and
other environmental factors. “Owing to the mobility of nitrate (NO3-), groundwater is vulnerable
to contamination from leaching; especially shallow unconfined aquifers” (Puckett 2011). A paper
by Farber about linking ecology and economics discusses the trade-offs and values of ecosystem
services (2006). We as a community have to place a value on pristine drinking water from the
aquifer and consider the replacement cost of that water supply if it is contaminated.
Broader Implications
“Groundwater in many urban and peri-urban areas
has been significantly affected by pollutants,
particularly nitrate” (McDonald 2011). Since, as
previously stated, drinking water in Florida comes
from groundwater; the fact that it may be
Figure 3 (http://water.usgs.gov/ogw/aquiferbasics/ext_surficiala.html)
contaminated is a frightening prospect.
As the population grows and urbanization continues to spread this trend is only going to increase.
While there are immediate concerns of contamination there are also future implications. “While
high nitrate levels can be a concern on their own, because of long groundwater residence times,
steadily declining water quality may result as the fraction of water that predates industrial
agriculture decreases with time. The net result is we are creating a N pollution legacy that may
affect future generations for decades to come.” (Puckett 2011).
A paper by Callicott discusses the concept of ecological sustainability and describes it as the
maintaining at the same place and the same time two interacting things (1997). For the purposes
of this study those two things are a bright green lawn and a clean drinking water supply. These
are two things that may not be able to continue to exist simultaneously unless preventative and
sustainable actions are taken.
“With the urbanization of Florida and the concomitant increase in fertilizer use by home owners,
there is growing concern about the impact of nutrient losses from conventional turf grass
landscapes as a result of surface water runoff and subsurface leaching” (Erickson 1999). Water
that is contaminated with nitrate is not drinkable and could be a health risk at high enough
concentrations (Andrews 2013). Studies have linked exposure to NO3 at concentrations lower
than the EPA and WHO standards to several cancers and negative birth outcomes (Puckett
2011).
In addition to the negative effects of fertilizer contamination on humans, there are many negative
effects on ecosystems.
“Much of the land cover in newly subdivided suburban lots may, in fact, consist solely of
turf grass and as suburbs begin to displace other land covers in the fringe belts
surrounding US cities, there is a parallel growth in the coverage of lawns. These bring
with them inputs of insecticides, herbicides, and fertilizer. This means changes in soil
profile, storm water runoff, water consumption, micro-fauna diversity, energy use, air
quality, and opportunities and constraints for terrestrial wildlife and nesting birds”
(Robbins 2003).
It is very important to understand how these systems work and interact with each other. While
simply applying fertilizer to one’s lawn to keep it green may seem innocent, there are larger
implications. As Erickson states in his paper, “fertilizer practices that minimize N runoff and
leaching are advantageous to both human safety and the environment” (1999).
With these definite problems in mind, we propose to find the best ground cover for UCF that
limits the amount of fertilizer leaching into the groundwater. A previous study by Cisar found
that very little N (<2%) leached from St. Augustinegrass (2001). Also, using the knowledge that
St. Augustinegrass requires the most fertilizer we hypothesize that if equal amounts of fertilizer
are applied to each St. Augustinegrass, Bahiagrass, and zoysiagrass, then when water is applied
at two different time intervals St. Augustine will filter the most fertilizer in both time periods.
Materials and Methods
In order to conduct this experiment there were 8-5 gallon buckets and 8 inserts in the buckets to
keep the piece of sod slightly elevated above the water that was poured over them. In addition,
we put a piece of window screen was put under the sod pieces in order to keep dirt particles from
getting into the bucket and water samples. Next 8 pieces of sod measured to fit the circumference
of the buckets for all three ground covers (St. Augustinegrass, Bahiagrass, and Zoysiagrass). In
order to conserve materials the experiment was ran on one sod type at a time over the course of
three days.
The basic experimental structure is demonstrated in figure 4. This experiment was replicated two
times for all of the sod types. Excluding the controls, the pieces of ground cover received 2
grams of fertilizer applied of the most common turf fertilizer used on campus, which is Turf Care
16-0-8 Pendulum pre-emergent. After the fertilizer was applied, each bucket was immediately
watered with a gallon of water using a watering can with a rain head attachment and waited 20
minutes before collecting an 8 oz. water sample from each bucket. Then, after 8 hours, the four 8
hour buckets were watered with one gallon, and after 20 minutes water samples were collected
from each bucket and immediately tested for the presence of N. The same procedure was
repeated with the four 24 hour buckets, after 24 hours from the start of the
experiment. Immediately after collection each water sample was tested for the presence of
nitrogen using a YSI (Ecosense 9500 photometer). In order to be able to compare the water after
being applied to sod we took 2 grams of fertilizer and dissolved it in 1 gallon of water and also
plain water with no fertilizer and tested for the amount of nitrogen present. The results from the
collections after 8 hours and 24 hours were multiplied by two to account for the extra gallon of
water present in the bucket.
St. Augustine
Control (No
fertilizer)
St. Augustine
Fertilizer
Applied
Bahia Control
(No fertilizer)
Bahia
Fertilizer
Applied
Zoysia Control Zoysia
(No fertilizer) Fertilizer
Applied
Time Since
Application
8 Hours
2x
2x
2x
2x
2x
2x
2x
2x
2x
2x
2x
2x
24 Hours
Figure 4. Experimental Structure
Results
Figure 5. Difference in the amount of nitrogen in the water supply immediately and after 8-hours in the control
buckets for St. Augustinegrass, Bahiagrass and Zoysiagrass.
Table 1. Percentage change in nitrogen in the buckets without fertilizer application
and in the buckets with fertilizer application over the 8-hour time period for three
grass species
Percentage Change in Nitrogen at 8-Hours
Grass Species
St. Augustinegrass
Bahiagrass
Zoysiagrass
Without
Fertilizer
41.82%
2200.00%
148.35%
With
Fertilizer
40.35%
1500.00%
55.14%
Figure 5 shows the amount of nitrogen in the control buckets immediately after initial watering
and after 8 hours watered again. This figure shows the amount in the control buckets was
different among St. Augustinegrass, Bahiagrass and Zoysiagrass in the beginning even without
fertilizer application by the scientists. After 8-hours, the nitrogen amount increased in those
buckets for all three of the grass species (Figure 5). This trend was also observed when the
percentage change in nitrogen was calculated after 8 hours, Table 1 shows that there was a
percentage increase in the buckets without added fertilizer. St. Augustinegrass had the smallest
percentage increase over the 8-hour time period in the control buckets (Table 1).
Figure 6. Difference in the amount of nitrogen in the water supply found immediately and after 8-hours in the
buckets with fertilizer application for St. Augustinegrass, Bahiagrass and Zoysiagrass.
Similar trends were found in the buckets with added fertilizer after the 8-hour period. For one,
the nitrogen amount measured immediately after applying fertilizer and water was different for
all the grass species (Figure 6). Furthermore, at the immediate measurement, Bahiagrass showed
the least amount of nitrogen in the water supply (Figure 6) which is consistent with the findings
in Figure 5. In addition, after 8-hours, the amount of nitrogen increased in the buckets with
fertilizer for all three grass species (Figure 6). St. Augustinegrass had the smallest percentage
change in the buckets with applied fertilizer, which is consistent with the findings in the control
buckets (Table 1). Table 1 also shows that when the percentage change in nitrogen amounts was
compared over the 8-hours between the buckets without fertilizer and the buckets with fertilizer
it was concluded that the percentage increase of nitrogen was smaller in the buckets with
fertilizer application.
Table 2. F-Test two-sample for variances between St.
Augustinegrass and Bahiagrass at 8-hours
St.
Augustine
Bahiagrass
Mean
0.02425
0.0045
Variance
0.000607583
0.000041
Observations
4
4
df
3
3
F
14.81910569
P(F<=f) one-tail
0.026464491
F Critical one-tail 9.276628153
Due to the fine particulate dirt substrate that the Zoysiagrass was grown on, the photometer did
not give accurate results for this species after initial water application. Therefore, this species
was left out of statistical analysis. First, in comparing St.augustinegrass and Bahiagrass, an FTest two-sample for variances between the two grasses for the 8-hour time period was ran to
measure how far the set of numbers was spread. The F-test results indicated the variances
between these two grass species were significantly different for fertilizer application after 8hours (P= 0.02646) (Table 2).
8-Hour Time Period
Buckets With Fertilizer Application
Nitrogen (mg/L)
0.120
0.100
0.080
0.060
St. Augustine
Bahia
0.040
0.020
0.000
Immediate
Time
8-Hours
Figure 7. Difference in the amount of nitrogen in the water supply found immediately and after 8-hours in the
buckets with fertilizer application for St. Augustinegrass and Bahiagrass, and displaying error bars with standard
deviation.
The error bars with standard deviation show in Figure 7 corroborate the trend found with the Ftest. The nitrogen amount found immediately as well as the nitrogen amount found after 8-hours
was statistically different between St Augustinegrass and Bahiagrass (Figure 7).
Figure 8. Difference in the amount of nitrogen in the water supply found immediately and after 24-hours in the
control buckets for St. Augustinegrass, Bahiagrass and Zoysiagrass.
Table 3 Percentage change in nitrogen in the buckets without fertilizer application
and in the buckets with fertilizer application over the 8-hour time period for 3 grass
species
Percentage Change in Nitrogen at 24-Hours
Grass Species
St. Augustinegrass
Bahiagrass
Zoysiagrass
Without
Fertilizer
255.56%
255.56%
9.90%
With
Fertilizer
448.39%
303.77%
-57.88%
The nitrogen amount measured immediately after applying one-gallon of water in the 24-hour
control buckets was different among St. Augustinegrass, Bahiagrass and Zoysiagrass (Figure 8).
Figure 8 shows that after 24-hours when the buckets were watered, the nitrogen amount
increased slightly in those buckets without fertilizer application for the three grass species.
Figure 9. Amount of nitrogen in the water supply found immediately and after 24-hours in the buckets with fertilizer
application for St. Augustinegrass, Bahiagrass and Zoysiagrass.
After immediate fertilizer and water application in the 24-hour buckets, the nitrogen amount in
the samples was different for all the grass species (Figure 9). Again, the trend in Zoysiagrass was
different than the trend found for the two other grass species. The amount of nitrogen in
Zoysiagrass decreased over the 24 hours (Figure 9). It was observed that at 24 hours the
percentage change in nitrogen decreased by almost 58% in the Zoysiagrass buckets with
fertilizer and was the only negative number found in the experiment, these results were
considered inconclusive and not used in data analysis(Table 3). St. Augustinegrass and
Bahiagrass had an increase in nitrogen after 24 hours (Figure 9). Bahiagrass had the smallest
percentage change over the 24-hour time period in the buckets in which fertilizer was applied
(Table 3).
Table 4. F-Test Two-Sample for Variances for St.
Augustinegrass and Bahiagrass at 24-hours
St.
Augustine
Bahiagrass
Mean
0.029
0.042
Variance
0.000563333
0.000721
Observations
4
3
df
3
2
F
0.781322238
P(F<=f) one-tail
0.396366943
F Critical one-tail 0.104689082
For the statistical analysis the F-Test two-sample for variances for St. Augustinegrass and
Bahiagrass at 24-hours indicated the variances between these two grass species were not
significantly different (P= 0.3963) (Table 4).
Figure 10. Graph showing the amount of nitrogen in the water supply found immediately and after 24-hours in the
buckets with fertilizer application, and displaying error bars with standard deviation for St. Augustinegrass and
Bahiagrass.
The error bars with standard deviation corroborate the trend found with the F-test for variances.
When the nitrogen amounts found immediately as well as the nitrogen amounts found after 24hours for St Augustinegrass and Bahiagrass were compared it was concluded that the nitrogen
amounts found were not statistically different (Figure 7).
Discussion
This experiment in sustainable ground covers gave results comparable with the hypothesis and
results that were extraneous to statistical analysis. Interestingly, every un-fertilized control plot,
regardless of grass species, showed increased N leaching over time. The results show that the
grasses were all previously fertilized, but at different levels due to coming from different
providers. The smallest percentage change in N occurred in the 8 hour time period with
St.Augustinegrass (Table 1). This means that of the three grasses, St. Augustine leached the
least amount of N. We conclude that St. Augustine will minimize N leaching into groundwater,
and will do this most efficiently if watered after 8 hours, and not 24. Our results show that of the
three grasses, St.Augustinegrass is the most sustainable lawn cover if only the filtration of
nitrogen is a consideration.
The 24 hour time period experiment was exclusive to the 8 hour time period, meaning the
buckets tested at each interval were separate from each other and the results for each time must
be discussed separately. With the 24 hour period for the three types of turfgrass, the results
concluded that Bahiagrass and St.Augustinegrass both had the same percentage change in N
leaching for the control plots that had no fertilizer added (Table 3). This means the Bahia and St.
Augustine controls filtered N at the same rate over 24 hours, while Zoysiagrass gave inconsistent
and extraneous results in both the control and experimental (fertilized) plots. In the fertilized
plots, Bahiagrass showed the least amount of N leaching over a 24 hour period, followed closely
by St.Augustinegrass (Table 3). These results confirm that while St.Augustine filtered N the best
at an 8 hour interval, over the 24 hour time interval, Bahia proved to filter N better than St.
Augustine. These results confirm a previously quoted author that stated that St.Augustine
requires more fertilizer and water, while Bahiagrass requires less fertilizer and watering
(Trenholm 2013). So while St.Augustine did filter out more fertilizer, that is because it requires
more fertilizer and more often, and this may not make it the most sustainable choice for a
groundcover.
Zoysiagrass’ measurements were overall inconsistent due to its different substrate and how the
photometer measured its N levels. The samples were not read accurately by the photometer,
which uses light to measure changes in coloration from a dissolved nitrogen reagent. Bahia and
St. Augustine both had visibly sandier substrates and their water samples were noticeably
clearer. If the Zoysiagrass were grown on a sandy substrate like the other grasses then possibly it
would show trends more similar to Bahia and St. Augustine’s ability to filter out N.
Application of Research
Our findings are important when considering the immense acres of land that are, and will be,
covered by one of these common turfgrasses. Take for example an upscale community that is
centered around a well-kept golf course. The grounds must be maintained and fertilized to an
extent where the groundwater below is continually being leached into. These communities are
unsustainable in their current use of ground covers. This example of expanded turfgrass cover
can also be applied to large sports complexes which will commonly be developed near sprawling
communities. They too cover large amounts of acreage with planted grasses and are consistently
watered and fertilized. Our research hopes to balance out this desire for expansive covers of
turfgrass and the need for a sustainable choice. Another example is the grassy shoulder of
roadways. These are usually roads that cut through natural habitats and have planted sods just
off their sides on the right and left shoulders. Although these grasses may not be fertilized after
they’re planted, it is evident from our research (specifically our control plots) that all planted
turfgrasses have been fertilized before and will leach N when water is applied.
There are certain harms associated with excess N in natural systems. Lakes are commonly
“aged” by excess amounts of nitrates in a process called eutrophication which depletes oxygen
levels and kills off fish. Likewise newborn babies are susceptible to a condition known as “blue
baby syndrome” if excess nitrates contaminate the water supply for drinking. Each of these
examples involves the inability for inorganic nitrogen to properly decompose over time
("Frequently asked questions," 2013). Evidence has shown that exposure to chemicals used in
lawn care may result in cancer, respiratory problems, skin rashes, and memory failure. (Keesling,
2003) These examples are known hazards from high levels of N and a more sustainable practice
in ground cover may prevent these negative effects of fertilizer use.
The most sustainable method for fertilization is socially promoting organic fertilizer use which
better facilitates nitrogen decomposition and promoting continual sustainable research. The
existing body of knowledge is very specific in its focus and our findings can facilitate research
done previously on Zoysia, St. Augustine, and Bahia grasses. Two recent studies are specific for
these grasses, but they only focus on phosphate leaching and lack specific enough details on
nitrogen leaching to be a comprehensive body of knowledge (Gonzales et al., 2013; Obour et al.,
2010). Our research is needed to accompany the existing findings so that the most effective and
sustainable body of knowledge can be used to prevent environmental damages.
The researchers have several suggestions for how to better this experiment for more accurate
results and better understanding. For example, in this experiment the researchers did not have
access to grass that had come from one provider and without the previous use of fertilizer and a
consistent substrate. If all three grasses had the same substrate and a level of 0 mg/l N to begin,
then this experiment would have yielded more accurate and useful results. A greater amount of
time intervals would also be able to provide a more broad view of when is the best time to water
a lawn after applying fertilizer. The research would also have benefitted from more replicates
within each time period as the experiment only included two replicates.
Further research is needed in this very important area in order for people and their desire for
residential homogeny to coexist with a healthy planet.
Works Cited
Andrews, M., & Lea, P. J. (2013). Our nitrogen 'footprint': the need for increased crop nitrogen
use efficiency. Annals of Applied Biology, 163(2), 165-169.
Bormann, F.H., Balmori, D., et al., 1993. Redesigning the American Lawn. Yale University
Press, New Haven.
Callicott, J. B. & Mumford, K. (1997) Ecological sustainability as a conservation concept.
Conservation Biology, 11, 32-40.
Cisar, J.L, Erickson, J.E., Snyder, G.H., Volin, J.C. 2001. Comparing nitrogen runoff and
leaching between newly established St. Augustinegrass turf and an alternative residential
landscape. Crop Science, 41.6, 1889.
Erickson, John E., Volin, John C., Cisar, John L., Snyder, George H. 1999. A facility for
documenting the effect of urban landscape type on nitrogen runoff. Proc. Fla. State Hort.
Soc., 112, 266-269.
Farber, S., et al. (2006). Linking ecology and economics for ecosystem management. BioScience,
56(2), 121.
Florida Department of Environmental Protection. 2007. Aquifers. Accessed
9/24/2013. http://www.dep.state.fl.us/swapp/aquifer.asp
Frequently asked questions. (2013, August 13). Retrieved from http://water.usgs.gov/owq/
FAQ.htm
Gonzales, R., Sartain. J., Kruse, J., Obreza, T., O'Connor, G., Harris, W. (2013). Orthophosphate
Leaching in St. Augustinegrass and Zoysiagrass Grown in Sandy Soil under Field
Conditions. JOURNAL OF ENVIRONMENTAL QUALITY, 42(3), 749-757. DOI:
10.2134/jeq2012.0233
Keesling, G., & Kaynama, S. A. (2003). An exploratory investigation of the ecologically
conscious consumer’s efforts to control water contamination: lawn care and the use of
nitrogen fertilizers and pesticides. Journal Of Marketing Theory & Practice, 11(1), 52.
McDonald, R. I., Douglas, I., Revenga, C., Hale, R., Grimm, N., Groenwall, J., & Fekete, B.
(2011). Global urban growth and the geography of water availability, quality, and
delivery. Ambio, 40(5), 437-446.
Miller, J. A. (1990). Floridan Aquifer System. USGS. HA 730-G. Accessed
9/23/2013. http://pubs.usgs.gov/ha/ha730/ch_g/G-text6.html
Obour, K., Silveira, M., Vendramini, J., Sollenberger, L., O'Connor, G., Jawitz, J. (2010).
Agronomic and environmental impacts of phosphorus fertilization of low input
bahiagrass systems in Florida. Nutrient Cycling in Agroecosytems, 89(2), 281-290
Puckett, Larry J., Tesoriero, Anthony J., & Dubrovsky, Neil M. 2011. Nitrogen contamination of
surficial aquifers- a growing legacy. Environmental Science and Technology,45,839-844.
Raciti, S., Groffman, P., Jenkins, J., Pouyat, R., Fahey, T., Pickett, S., & Cadenasso, M. (2011).
Nitrate production and availability in residential soils. Ecological Applications, 21(7),
2357-2366.
Robbins, P., & Birkenholtz, T. (2003). Turgrass revolution: Measuring the expansion of the
American lawn. Land Use Policy, 20(2), 181-194.
Robertson, G.P., Vitousek, P.M., 2009. Nitrogen in agriculture: Balancing the cost of an
essential resource. Annu. Rev. Environ. Resour. 34, 97–125.
Stiglbauer, J., Liu, H., McCarty, L., Park, D., Toler, J., & Kirk, K. (2009). 'Diamond' Zoysiagrass
Putting Green Establishment Affected by Sprigging Rates, Nitrogen Sources, and Rates
in the Southern Transition Zone. Hortscience, 44(6), 1757-1761
Trenholm, L. E., Cisar, J. L., Unruh, J. B. (2013). St. Augustinegrass for Florida Lawns. University of
Florida IFAS Extention. September 23, 2013. http://edis.ifas.ufl.edu/lh010.
Trenholm, L. E., Unruh, J. B., & Sartain, J. B. (2013). Nitrate leaching and turf quality in newly
sodded st. Augustine. Informally published manuscript, University of Florida, Gainsville,
Florida, Available from Taylor Francis Online.
Van Beynen, P., Niedzielski, M., Bialkowska-Jelinska, E., Alsharif, K., & Matusick, J. (2011).
Comparative study of specific groundwater vulnerability of a karst aquifer in central
Florida. Applied Geography, 32(2), 868-877.
Whitney, K. (2010). Living lawns, dying waters: the suburban boom, nitrogenous fertilizers, and
the nonpoint source pollution dilemma. Technology And Culture, (3), 652.
doi:10.2307/40927990
Comparative Study of Chlorophyll a Before and After Chemical Treatment
Megan Selva
University of Central Florida
BSC 3905
Abstract
Stormwater retention ponds are constructed in urban environments to prevent flooding and
filter pollutants. Pollutants collect in runoff from streets and fertilizers. Stormwater pond
systems hinder what would otherwise flow into surrounding natural water bodies. Analyzing
the concentrations of Chlorophyll a, the photosynthetic pigment found in algae, is a good
indicator of how much algae is present in a pond, as well as the level of other nutrients.
Chlorophyll a is a natural occurring substance and is not considered harmful because it is
found in all phototrophic biomass, but does exist in toxic algae. If there are algae blooms this
means there are high amounts of Chlorophyll a. The purpose of the study is to test the amount
of Chlorophyll a in seven retention ponds around the University of Central Florida main
campus before and after chemical treatment to see if it effects the amount of Chlorophyll a
concentrations present.
Introduction
Stormwater retention ponds are constructed in urban environments to filter pollutants
that collect in runoff and would otherwise flow into surrounding natural water bodies. They
also function as a tool to control flooding in urban areas. Monitoring storm water retention
ponds is important because an “accumulation of urban contaminants can lead to a number of
water quality problems including high nutrient, chemical contaminant, and bacterial levels”
(Serrano, p.43).
Chlorophyll a is one of the primary components in plants to perform photosynthesis
which is a vital life process in which plants produce oxygen and energy from sunlight.
Chlorophyll a is not considered a harmful substance, as it is found in all phototrophic
biomass, but it should be noted that it can indicate existence of toxic algae. Cyanobacteria
(blue-green algae) can become toxic algae when high levels of nutrients enter the water and
enables the algae to accumulate. This creates blooms that develop a paint-like appearance and
kill fish and other aquatic life. A healthy concentration of Chlorophyll a is an average 0-10
μg/L a year (Wicomico Creekwatchers, p.3). Chlorophyll a, being the most abundant form of
Chlorophyll, gives plants their green color. The University of Central Florida has over 10
storm water and natural ponds. These ponds eventually flow out into the St. John’s River
basin, therefore it is important to monitor the health of the storm water systems to prevent the
spread of pollution, non-native nuisance species and eutrophication and to promote cleaner
water.
Chlorophyll a concentration is a good indicator of the amount of algae present in a
storm water pond. Along with other environmental factors, it plays a key role in water
resource management (Jing, 2015). Various chemicals are used to control growth of algal
blooms, nuisance weeds. The concentration of Chlorophyll a directly correlates with the
amount of nutrients in the ecosystem because excess nutrients means more algae growth. This
could be a problem for the overall health of the aquatic ecosystem. As nutrient levels
increase, the level of Chlorophyll a increases leading to higher levels of blue-green algae
causing oxygen depletion, bacteria growth and a decreased aesthetic clarity of the water due
to high turbidity.
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Pesticides used in the UCF stormwater retention ponds include glyphosate and liquid
copper with occasional treatment of Imazapyr and Diquat. Target vegetation of the treatment
are Torpedo grass (Panicum repens), Hydrilla, algae, Cogon grass (Imperata cylindrical) and
other invasive and nuisance species. Glyphosate is an herbicide used widely through the
United States for eradicating herbaceous and woody weeds found around wetlands
(EPA.org). Liquid copper algaecide is used mainly to control algae growth, but is toxic to fish
and aquatic invertebrates due to oxygen depletion when the algae decays (Southern
Agricultural Insecticides, Inc., p.1). According to the Weed Control Methods Handbook by
Tu et al, “Imazapyr is a non-selective herbicide used for the control of a broad range of
weeds including terrestrial annual and perennial grasses and broadleaved herbs, woody
species, and riparian and emergent aquatic species” (p.7h.1). Pollution runoff from
transportation, industrial waste and fertilizers contribute to eutrophication which inhibits the
amount of oxygen in the water. This causes fish kills, algae blooms and spread of non-native
nuisance species. Analyzing the concentrations of Chlorophyll a, the photosynthetic pigment
found in algae is a good indicator of how much algae is present in a pond. If there are algae
blooms this means there are high amounts of Chlorophyll a.
The purpose of the study is to test the amount of Chlorophyll a concentrations in
seven retention ponds around the University of Central Florida before and after chemical
treatment to see if it effects the concentration amount of Chlorophyll a that correlates with
algae production. I hypothesize that chemical treatment regimens will reduce the amount of
algal growth, therefore reducing the production of Chlorophyll a in all storm water ponds.
Materials and Methods
Materials
50 ml digestion tubes
Pipettes
Sharpie
Water filtration unit
Glass Fiber Prefilter paper
Aluminum foil
Tweezers/forceps
250mL Sampling bottles
Dissolved Oxygen probe
Ziploc bag
Centrifuge
pH and Conductivity probe
95% Ethanol
Cooler with ice
Methods
Student researchers collected samples out in the field on Tuesdays from 8:00am to
11:00am and worked in the laboratory on Wednesdays from 8:00am to 11:00am starting June
9th until July 30th 2015. Seven ponds (1C, 1F, 2H, 4B, 3A, and 4R) were sampled lasting
about 25 minutes each (refer to figure 1). One untreated wetland pond (W1) was used as the
control (shown in figure 1). They tested two consecutive weeks before chemical treatment
and then two consecutive weeks after for a total of eight weeks. Treatments were conducted
on June 24th, 2015 and July 15th, 2015 by Bio-Tech Consulting Inc. The four pesticides used
to control nuisance vegetation, hydrilla and algae were Liquid Copper, Diquat, Glyphosate
and Imazapyr. On collection days, location, time, pH, Dissolved Oxygen, conductivity,
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temperature, and ambient conditions were recorded when available, in addition to
Chlorophyll a.
Samples were collected just below the water surface with a collection extender arm of
eight feet. Three different areas of the stormwater ponds were sampled resulting in three
samples per pond. The next step was to grab the 250 mL sample bottle and rinse it three times
in the lake before collecting the sample. After collecting from each pond, sample bottles were
brought back to the lab in coolers with ice to keep the specimens preserved. In order to test
the Chlorophyll a, samples were filtered using a filtering unit.
Using clean tweezers, the glass fiber filter (GFF) was placed on the filter holder to
prepare the filter apparatus. Samples were inverted and then poured into the filter unit until
the bottom unit was full. Make sure to keep track of volume of sample being used. Once there
was enough green algae on the GFF it was extracted with tweezers and folded into a burrito,
put in a sample centrifuge tube, and used large pipette to add 10 mL of Ethyl alcohol. Using a
spatula, filter was crushed until it dissolved. The digestion tubes were then capped and placed
overnight in a dark area. Aluminum foil was used to cover them. The following day digestion
tubes were placed in centrifuge and put it to the maximum speed of 3000 rpm for 10 minutes.
The process was repeated for samples that did not separate all the way from the filter. After
sample was spun, digestion tubes were checked to see if filter residue was at the bottom. Each
sample supernate was pipetted 300uL into microplate and ran the chlorophyll a analysis on
the spectrophotometer.
Spectrophotometer
Spectrophotometry is a method used to determine the amount of chlorophyll in surface water
(YSI Environmental). We set up an equation retrieved from University of Colorado Boulder
(p.2) for finding the concentrations of chlorophyll a in each pond. The spectrophotometer
was set to scan between 649 nm and 750 nm.
Equation:
Chl a (μg/L) = (13.7(A665-A750)-5.76(A649-A750)) v
V*l
V = volume (L) of sample filtered
v = volume (mL) of extract
l = pathlength of spectrophotometer curvette, in cm
Results
Results show that there is a slight increase in concentrations of chlorophyll a after herbicide
spray in all seven stormwater ponds sampled. Table 1 lists the amount of chemicals and the
chemicals used on June 24th and July 15th. Liquid Copper, Diquat Glyphosate and Imazapyr
were the four pesticides used to treat the six stormwater ponds. Table 2 shows the
Chlorophyll a collection dates with average concentrations of each pond before and after
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treatment. On July 7th, IF had the highest concentration of algae with 10.77 μg/L of
chlorophyll a, but overall 4R had the highest increase of 3.68 (68% increase). Pond 3A had
the lowest concentrations overall and lowest change of 0.15 (15% increase). July 7th has a
trend with the most ponds having a high concentration. Graph 1 is a visual diagram showing
the date and concentrations before and after treatment. Overall, ponds 4R, 1F, 1C, W1 and
3A all increased from pre-treatment to post-treatment. Ponds 4B and 2H both decreased after
July 15th treatment.
4R
Stormwater pond 4R increased from 1.72 to 5.19. This was the largest change out of all seven
ponds treated. It had a 68% increase in chlorophyll a concentration after treatment. 320oz of
Liquid Copper and Diquat were sprayed on June 24th and June 15th in this pond. The most
significant change occurred on July 7th with a concentration of 10.62 μg/L. The lowest
concentration was on July 14th with 1.22 μg/L, the following week.
4B
Stormwater pond 4B increased from 2.78 to 2.60, indicating a .04% increase. This is not a
significant change. 16oz of Glyphosate and 4oz of Imazapyr were sprayed around this pond
on June 24th. Then on July 15th 12oz of Glyphosate, 6oz of Imazapyr and an added 20oz of
Endothall was applied to rid of algae. The lowest recorded concentration in this pond was on
June 16th with 1.5 μg/L. The highest concentration was on July 7th with 3.43 μg/L.
1F
Stormwater pond 1F had higher concentrations pre-treatment, as well as post treatment out of
all the ponds. Starting with an average of 7.01, it increased to 8.56 resulting in a 14%
increase in chlorophyll a concentration. Glyphosate and Imazapyr were used to treat this
pond. Both increased in usage almost by double (refer to Table 1). The highest concentration
was on June 9th with 11.06 μg/L and the lowest was July 14th with 3.1 μg/L.
1C
Stormwater pond 1C had a 0.76 (22%) increase in concentration. The highest recorded
concentration was on July 28th with 4.99 μg/L and the lowest was on June 16th with 1.87
μg/L. The pesticides used on this pond were Glyphosate and Imazapyr. The amount of
Glyphosate used in this pond decreased from 16oz to 12oz, while Imazapyr stayed the same.
W1
W1 was our control pond wetland. No treatment is used on this pond, but it still had a
dramatic increase from 2.84 to 4.56 μg/L. With a 42% increase, the control comes in second
after 4R. The highest recorded concentration was on July 7th with 5.36 μg/L and the lowest
was on June 9th with 2.16 μg/L.
2H
Stormwater pond 2H had a slight increase from 2.56 to only 2.43 μg/L. It only increased by
about 1%. Glyphosate and Imazapyr were used to treat this pond. The highest recorded
concentration was on July 14th with 3.21 μg/L and the lowest was on June 9th with 2.13 μg/L.
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The pesticide usage for this pond increased from 32oz and 8oz of Glyphosate and Imazapyr
to 60oz and 22oz.
3A
Stormwater pond 3A had the lowest concentrations overall. It had a slight increase from 0.84
to 1.05 μg/L, indicating a 15% increase. The pesticides used to treat this pond were Liquid
Copper and Diquat. The amount used to treat the pond increased from 230.4oz both
pesticides to 320oz. The highest concentration recorded was on July 7th with 1.28 μg/L and
the lowest concentration recorded was on June 16th with 0.64 μg/L.
Graph 1.
Table 1.
Pond
Date
4R
4B
1F
Treatment (oz)/Concentration
24-Jun-15
320oz Liquid Copper/(2gal/acre)
320oz Diquat/(2gal/acre)
16oz Glyphosate/(1.5%)
4oz Imazapyr/(0.5%)
16oz Glyphosate/(1.5%)
6oz Imazapyr/(0.5%)
1C
16oz Glyphosate/(1.5%)
6oz Imazapyr/(0.5%)
2H
32oz Glyphosate/(1.5%)
8oz Imazapyr/(0.5%)
3A
230.4oz Liquid Copper/(2gal/acre)
230.4oz Diquat/(2gal/acre)
W1 (Control) No Treatment
Treatment (oz)/Concentration)
15-Jul-15
320oz Liquid Copper/(2gal/acre)
320oz Diquat/(2gal/acre)
12oz Glyphosate/(1.5%)
6oz Imazapyr/(0.5%)
20oz Endothall/(2gal/acre ft.)
24oz Glyphosate/(1.5%)
12oz Imazapyr/(0.5%)
12oz Glyphosate/(1.5%)
6oz Imazapyr/(0.5%)
60oz Glyposate/(1.5%)
22oz Imazapyr/(0.5%)
320oz Liquid Copper/(2gal/acre)
320oz Diquat/(2gal/acre)
No Treatment
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Table 2.
Pre-Treatment (μg/L) Post Treatment (μg/L)
Ponds
Average
Average
4R
1.72
5.186
4B
2.78
2.6
1F
7.01
8.562
1C
2.67
3.776
W1 (Control)
2.84
4.556
2H
2.56
2.428
3A
0.84
1.052
Discussion
There were many environmental and human factors that play a part in collecting,
analyzing and presenting the data. Variables that affected the outcome of the research were
locations of stormwater ponds, if they were near irrigation, lab errors, as well as plant
decomposition and weather. Also, we used an 8 foot extension arm to collect water.
Collecting in middle of a lake would have be more desirable. IF, 4B, and IC all have
irrigation near them, so this could be a factor for the higher algae concentration in IF and IC.
UCF uses reclaimed water in their irrigation, so nutrients and contaminants may have
affected the results. Stormwater pond IF is also next to a parking garage and surrounded by
roads and buildings so runoff in this pond could have accumulated more pollution than other
stormwater ponds producing higher algae substance.
Pond 4B is near a natural cypress swamp ecosystem, which could help filter any
pollution from the runoff. Compared to the control, 3A had the lowest concentration of algae
growth before and after treatment. This means that there is low nutrient levels because
“chlorophyll a levels increase with nutrient levels” (Hansen, p.5). This could be because a
lower amount of pesticide is used to treat this pond and it is further from roads and buildings.
The data for 4R has a large increase change because one sample spilled in the process of
extraction in the lab. This could have affected the accuracy of the average concentration of
this pond in the before data. 4R is also located next to a road.
Our control was a pond wetland, which had a more acidic pH and surrounded by more
vegetation and shade than the other ponds. Also, summer is the growth season due to high
amounts of rain and sunshine. The water levels fluctuated every week with some being much
higher than others. This made it hard to get more towards the middle of the pond. Also,
pollution from nearby roads in an urban environment could have caused higher nutrient levels
from runoff. This could contribute to the higher amounts of Chlorophyll a concentration
extracted from this natural ecosystem. The pond was aesthetically pleasing and had a pretty
stable concentration only increasing slightly due to these certain environmental factors.
Conclusion
I hypothesized there would be less concentration of chlorophyll a production meaning less
algae growth in the ponds following chemical treatment. However, my hypothesis was
proven wrong by the results I obtained. The results showed that there was an increase overall
in the amount of chlorophyll a after treatment had occurred in all the ponds, including the
control. Compared to the control, Chlorophyll a levels were normal and the levels fluctuated
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every week. According to various studies, a healthy concentration of Chlorophyll a is an
average 0-10 μg/L a year (Wicomico Creekwatchers, p.3). All of our ponds were under 10
μg/L within a two month period. I analyzed the concentrations of Chlorophyll a compared to
the control wetland pond prior to and after chemical treatment. By measuring Chlorophyll a,
we were able to get a general idea about the health of the ponds. There was no indication of
algae blooms or a significant amount of algae in any pond. The increase in chlorophyll a
concentrations could be from detriment from dead plants and algae or growth from higher sun
exposure do to the summer season. According to St. Johns River Water Management District,
this season, spring through early fall is typically known for higher ratios of algae.
Fortunately, the ponds algae concentrations studied were not significant enough to be
considered toxic. For further research a quantitative or qualitative analysis is needed on
existing algae and vegetation to get a full examination on the healthiness of the stormwater
pond ecosystems. Overall, it was a great experience and I learned an array of information
about stormwater management and laboratory techniques. I was able to get hands on
experience, although challenging at times, it will only benefit me in the future.
Figure 1.
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Literature Review
Bostrom, Mark et al. Sample Collection and Laboratory Analysis of Chlorophyll-a. (2008).
Web. 28 May 2015.
Diquat Chemical Fact Sheet. Wisconsin Department of Natural Resources. January 2012.
Web. 28 May 2015. Retrieved from:
http://dnr.wi.gov/lakes/plants/factsheets/DiquatFactsheet.pdf
Hansen, Dennis L. Chlorophyll Analysis. NEORSD. Web. 28 May 2015.
http://www.ohiowea.org/docs/Wed0900Lab_Chlorophyll_Analysis.pdf
Liandong, J., Hongyi, A., Xiaolong, H., Xiong, X., Chenxi, W., & Jiantong, L. (2015). Water
Environment Characteristics at Taige Canal-Taihu Lake: a Comparative Study on Interaction
between Chlorophyll a and Environmental Variables. Polish Journal of Environmental
Studies, 24(3), 1031-1039.
Liquid Copper Fungicide. Southern Agricultural Insecticides, Inc. Web. 28 May 2015.
Retrieved from: http://www.domyownpestcontrol.com/msds/100048940_product_label.pdf
Serrano, L., & DeLorenzo, M.E. “Water Quality and Restoration in a Coastal Subdivision
Stormwater Pond”. Journal of Environmental Management 88 (2008): 43-52. ScienceDirect.
Web. 7 August 2015.
St. Johns River Water Management District. 3 June 2014. Web.
http://floridaswater.com/algae/.
Technical Factsheet on: Glyphosate. EPA.gov. Web. 28 May, 2015. Retreived from:
http://www.epa.gov/ogwdw/pdfs/factsheets/soc/tech/glyphosa.pdf
Tu et al. Weed Control Methods Handbook. The Nature Conservancy. Web. 6 August, 2015.
Retrieved from: http://www.invasive.org/gist/products/handbook/17.Imazapyr.pdf
Chlorophyll a (Chl a) by Spectrophotometry with Ethanol Extraction (260903). University of
Colorado Boulder. Web. June 10, 2015.
YSI Environmental. “The Basics of Chlorophyll Measurement”. Tech Note. Web. 28 May
2015.
Wicomico Creekwatchers. Wicomico River Creekwatchers: 2014 Water Monitoring Results.
2014. Web. 21 August 2015.
https://www.salisbury.edu/wicomicocreekwatchers/docs/2014_CreekWatchers_Report.pdf
Wisconsin State Lab of Hygiene. “ESS Method 150.1: Chlorophyll- Spectrophotometric”.
Environmental Science Section 3.4 (1991): 359-363. Web. 28 May 2015.
Selva 8
Comparative Study of Pleurotus Djamor
Cultivation on Sustainable Waste Substrates
Obuasi Boulware, Jonathan Carr, Julie Deslauriers, Shannon Foley, and Victoria Kreinbrink
BSC 4861L, Department of Biology, University of Central Florida
Orlando, FL 32816, USA
Abstract
Fungi are diverse and essential to the health of many ecosystems. They break down
organic material from waste and in turn are able to provide other organisms with essential
nutrients. Mushrooms are critical to the health of Earth because they recycle tremendous
amounts of waste. This experiment tested the productivity of 4 different recycled substrates and
their ability to produce the largest final mass of Pleurotus Djamor. Oak mulch, palm mulch,
coffee grounds, and a mix of all three were tested. The levels of mycelium growth were measured
rather than mushroom mass due to time constraints. The mixed substrate was predicted to have
the best results; however, coffee surpassed it and had the overall fastest development times. The
mixed substrate had the second quickest colonization, the palm mulch came in third, and oak
mulch mycelium growth was the least, never surpassing 20%. Although coffee had the quickest
colonization rates, the experimenters determined the mixed substrate to be the most sustainable
because of coffee’s vulnerability to environmental factors. Even though this is a small-scale
experiment, certain outcomes may lead to future large-scale changes, thus reducing the amount
of waste in public spaces by a noticeable amount.
Introduction
For hundreds of years, scholars have
been debating the carrying capacity of earth
in relations to the logistic growth model.
Carrying capacity is the maximum
population size that an environment can
support (Campbell et al. 2011). With over
seven billion people on Earth, when will
Earth reach its maximum carrying capacity
and what will cause the human population
decrease? Could it be that human’s leading
predator is waste itself?
According to a recent BBC
publication on global waste production, the
average American produces over 700 kg of
waste per year (BBC, 2013). That means
each person in the United States produces
1,543 pounds of trash each year. An average
college student (21 years old) has already
produced 16.2 tons of trash over their
lifetime. At this rate, if an American lives
for 80 years, they produce roughly 62 tons
of trash. Putting it in a different perspective,
an 80-year-old person produces a quantity of
waste that is equivalent in mass to about
approximately 31 elephants. If we compare
this trend to the entire planet, Earth’s 7
billion inhabitants produce 5 billion tons of
trash each year.
This waste comes from the Linear
Model of Production, a very common model
used in industrialized countries. There is a
long history of linear models of economic
activity, tracing back to Soviet economists
material balance tables (Blume). These
1
models fluctuate between general and partial
equilibrium and have no recycling pattern to
balance the system (Blume). More
production means more disposal and in this
linear model, there is no use for the waste.
As seen in Figure 1, businessmen go home
happy with their paycheck, but will they be
happy when the Earth’s resources are
barren?
Figure 1: Diagram From Story of Stuff by
Annie Leonard (Leonard, 2007).
Where does all this waste go? If
there were no decomposers, this waste
would suffocate the planet and massively
pollute living conditions. It is easy to say
that without decomposers, trash really would
be a human ‘predator’ and the carrying
capacity of Earth would have been reached
hundreds of years ago. However,
decomposers are essential organisms that
degrade organic materials into a form that
can be easily utilized by other organisms.
Decomposers in nature often form a
sustainable cycle of death, growth, and birth.
When biotic organisms die, decomposers
grow from the remnants and break down the
larger molecules into a form more readily
for plant uptake (Stamets, 2000).
Sustainability is the key focus of this
experiment.
The
three
pillars
of
sustainability, people, planet, and profit, are
of utmost importance in order for a system
to maintain itself (Bernard, 2013). This
experiment was designed to maximize
“profit” through using free, recycled
materials as growing mediums for
mushrooms that can be sold. Through using
a variety of natural, readily available
resources, this experiment explores the most
effective substrate for mushroom
cultivation. This experiment also focuses on
“planet”, as the mushrooms will potentially
degrade their substrates sufficiently enough
to be used as compost, which in turn can be
used to grow other plants. “People” were
also focused on through the use of purely
waste products as the substrates. Even
though this is a small-scale experiment,
certain outcomes may lead to future largescale changes, thus reducing the amount of
waste in public spaces by a noticeable
amount. These three pillars of sustainability:
people, planet, and profit are all benefitted
by the closed loop system created by
decomposers (Figure 2, pg. 3).
Edible mushrooms, particularly fast
growing ones, such as Pleurotus spp. can
successfully form a closed loop system. The
first part of the system is to provide an
edible product (mushrooms) by using waste
byproducts (i.e., coffee grounds, tree
trimmings, palm fronds, etc.) as the growing
2
medium. Once the mushrooms have been
sold, the spent substrate can in turn be
composted and eventually converted into
fertilizer to add nutrients back into the soil.
The fertilizer encourages other plant growth
and eventually cycles around to produce
more mushrooms (Rinker, 2002). If not used
for compost, the spent substrates can be
utilized to produce animal feed or other
crops and purify water and soil (Rinker,
2002).
making products ranging from bread to
antibiotics” (Campbell, 2008). Also, human
nutritional needs are met by the fruiting
body of the mushroom. Commercial
mushroom producers could benefit greatly
and increase their profit by creating their
“product” from free, recycled substrates.
While humans have already found a wide
range of uses for the products and services
produced by these organisms, there is still
room for further incorporation into societies’
Figure 2: Sustainable Cycle of Pleurotus Djamor
everyday means of operation.
According to an article published in
Conservation
Biology,
“Ecological
Sustainability as a Conservation Concept”,
sustainability is achieved by meeting human
needs without compromising the health of
an ecosystem (Callicott, 1997). Mushrooms
exceed these criteria for sustainability by
benefitting the ecosystem with a wide array
of ecosystem services. “Humans benefit
from fungi’s services to agriculture and
forestry as well as their essential role in
Decomposers can be separated into
the 5 phyla of fungi, or Eumycota (Campbell
et al. 2011). Fungi are diverse and essential
to the health of many ecosystems. They
break down organic material from useless
waste, and provide other organisms with
essential nutrients. The 5 phyla of fungi
include:
chytrids,
zygomycetes,
glomeromycetes, ascomycetes (sac), and
3
basidiomycetes (Campbell et al. 2011).
Basidiomycetes, or mushrooms, are the most
commonly known phyla of fungi and will be
the main focus of this experiment.
Similar to plants, basidiomycetes
disperse their genetic material via aerial or
water dispersal in seed-like capsules known
as spores. The visible part of a mushroom is
actually an entire fruiting body, woven with
reproductive hyphae in thread-like structures
(Campbell, 2008). The fungi produce a
fruiting body above ground in order to
maximize the surface area in which the
spores will be exposed too. After the spores
are released, they spread out in search of
nutrients and a stable place for survival
(Campbell, 2008). Substrate is focused on in
this experiment because ideal substrate and
climatic conditions are essential for maximal
mycelia growth and mushroom production.
Substrates chosen for this study were
recycled materials that could all be found
within the UCF campus. Coffee was chosen
because it has high nitrogen content and has
been used many times as additives to
traditional substrates. Oak mulch was
chosen due to the observation that
mushrooms often typically grow on trees,
such as oak, in nature. Lastly, palm mulch
was chosen because palm trees are an
abundant natural resource in Florida. As
well, many previous studies have been
found to test palm fronds as a substrate with
success (Kalita & Mazumder, 2001). A
blend of all three substrates will also tested
be as a fourth trial. Hypothetically,
Pleurotus Djamor mushrooms should
produce at the highest yield on the blend of
coffee grounds, oak mulch, and palm fronds
because each substrate will contribute to
maximize the nutrient content.
The UCF Arboretum supplied the
oak mulch and palm mulch. Campus coffee
shops supplied the coffee.
substrates in the experiment
available, inexpensive, and
alternative uses, which make
substrates for this experiment.
All three
are readily
have few
them ideal
Additional components that are
typically used to increase mycelia growth
and mushroom production such as rice bran,
calcium carbonate, and cottonseed oil will
not be used in this experiment (Stamets,
2000). This is to allow direct observation of
each individual substrate’s ability to provide
adequate conditions for mycelia growth and
mushroom production. For example, coffee
already has high nitrogen content, and
adding an additional source of nitrogen is
unnecessary. Also, adding supplements to
the substrate increases production costs and
creates a need for stricter sanitation
(Stamets, 2000).
The species, Pleurotus Djamor, was
chosen for this experiment for many
reasons. Pleurotus cultivation popularity has
recently increased due to its desired taste as
well as numerous nutritional and medicinal
benefits. In 2008, oyster mushrooms rose to
the third most commercially produced
mushroom in the world (Dundar, Yildiz,
2008). P. Djamor prefers tropical and
subtropical regions and is known for its
“speed to fruiting, adaptive ability to
flourish on a wide variety of base materials,
and high temperature tolerance” (Stamets,
2000). Also, P. Djamor grows on a wider
range of forest and agricultural waste
products than any other species within the
basidiomycota phyla. In past research, P.
Djamor has been cultivate on most all
hardwoods, on wood by-products (sawdust,
paper, pulp sludge), all the cereal straws,
corn and corn cobs, sugarcane bagasse,
coffee residues (coffee grounds, hulls, stalks
and leaves) banana fronds, cottonseed hulls,
agave waste, soy pulp, and numerous other
4
materials containing lignin and cellulose
(Stamets, 2000).
Further research within this genus
has been stressed due to the species’
adaptability. The potential to utilize
otherwise considered waste products has
been studied as a means of reducing hunger
in developing nations (Anoliefo et al.,
1999). Other research has been performed
about the bioremediation abilities of P.
Djamor. When grown on materials
containing significant levels of mercury they
have been found to accumulate these heavy
metals from the ground. Growing
mushrooms in such conditions may not be
useful for human consumption but can play
valuable role in the bioremediation of
contaminated ecosystems (Bressa et. al,
1988). In a study done by Paul Stamets,
oyster mushrooms were used to breakdown
residual oil in soil in a lot near a high traffic
area resulting in significantly less oil in the
soil and mushrooms free from petroleum
residues (Stamets, 1999). Pleurotus spp.
have also been shown to stun and digest
nematodes for access to necessary nitrogen,
which can be a nuisance in agriculture and
water quality (Thorn and Barron, 1984).
largest final mass of Pleurotus Djamor. A
total of six trials were performed for each
substrate, creating an overall test of 24
substrates (Table 1).
A 25 lb. bag of Pleurotus Djamor
Sawdust Spawn was ordered from an online
distributor (www.everythingmushrooms.com).
The recycled substrates were collected
directly from the University of Central
Florida campus to portray the accessibility
and sustainability of the chosen substrates.
The UCF Arboretum provided the oak
mulch and palm mulch. A local campus
coffee shop provided the coffee grounds.
Methods
Coffee
Trial 1
x3
Trial 2
x3
Oak
Palm
Mulch Mulch
x3
x3
x3
x3
Blend
x3
x3
Table 1: Testing the substrates consisted of 3
replicates of each substrate, for a total of 24
jars. Overall, there were 6 jars of coffee ground
substrate, 6 jars of oak mulch substrate, 6 jars
of palm debris substrate, and 6 jars with a
proportional mixture of all three substrates.
This experiment was designed to test
the productivity of 4 different recycled
substrates and their ability to produce the
Figure 3: Above- Substrates were submerged in
water in order to reach 100% moisture content.
Below- To reach 55-65% moisture percentage,
substrates with excess moisture were baked at
350°F for 15 min intervals.
The growing mediums (coffee, oak
mulch, and palm mulch) were collected in
5
separate five-gallon buckets and submerged
in water. The substrates were soaked for
about three hours to ensure 100% moisture
content. The wet substrates were then laid
out on tarps to sundry for 3 hours.
Initial moisture content is of utmost
important for proper mycelium growth.
Many hobbyists use a method called the
palm test to determine proper moisture. The
palm test is determined by squeezing a
handful of substrate. If the substrate is
squeezed and it drips, the moisture content is
too high. Optimal moisture content is
achieved when wet substrate is squeezed and
no water drips out (Stamets, 2000). There is
another method called the oven method
(described below). This method is typically
preferred by scientists. In this experiment,
the oven method was used to get more
consistent moisture content in the substrates.
was too high, the substrate was baked at 350
degrees for15 minute intervals.
The substrates were then placed in
baking trays, covered, and heated to 160° F
for one hour by oven. Each substrate was
then placed into an individual autoclaved
wide mouth glass quart jars. Pleurotus
Djamor spawn was layered within the
substrate to ensure thorough colonization In
order to minimize risk of contamination; this
step was completed under a laminar flow
hood. The jars were then capped, labeled
accordingly, and placed in a dark incubation
room at ideally 75-85° F.
Initial Moisture Content Per Substrate
Trial 1
Trial 2
Coffee
62.70%
61.60%
Palm
58.70%
57.67%
Oak
62.43%
61.79%
Table 2: The initial moisture percentage for
both trials. Moisture percentage was
determined by subtracting the dry mass from
the wet mass, dividing the total quantity by the
dry mass, and multiplying by 100.
The mass of one cup of each
substrate was found using a gram scale. The
dry substrate mass was subtracted alongside
the experiment by placing a cup of each
substrate in the oven at 350°F for 1 hour.
The dry and wet masses were used to find
the percent moisture content, ideally aiming
for 55% to 65%. Proper moisture is essential
for mycelium colonization, and 55% to 65%
moisture content is the optimal condition
(Stamets, 2000). If the percentage was too
low, water was added, and if the percentage
Figure 4: Capped jars were placed in a dark
incubation room at 75-85° F.
Over the colonization period, the
amount of mycelium growth in each jar was
observed every two days. The data was
recorded based on visual observation of the
quickness and quality of mycelium growth
per substrate. Due to time constraints of this
class, the data cut off point was collected
before
full
mycelium
colonization.
Therefore, results were recorded in
mycelium growth. However, the experiment
continued and just a few days after the data
cut off point, the jars were fully colonized
and ready to fruit.
At around 100% colonization (about
24 days), the jars were uncapped and placed
in a terrarium containing 100% humidity for
6
fruiting. The jars were wrapped in aluminum
foil to encourage vertical growth.
prediction that the mixed substrate would
have the greatest success in growing
mushrooms.
Figure 5: Jars covered in aluminum foil in
terrarium.
Results
The results of this experiment were
measured as a percentage of visible
mycelium growth rather than mass of
fruiting bodies due to time constraints. As
visible in Figure 6, coffee had the overall
fastest colonization time within this
experiment. Coffee was followed by the
mixed substrate, which had the second
fastest colonization time, and palm mulch
finished third. Oak mulch had barely any
colonization remaining less than 20%
throughout the experiment.
Additionally, the second run of the
experiment had faster development times
than the previous run. This held true for all
four substrates being tested. The mixed
substrate’s second trial results developed at
the same pace as the first trial of coffee, only
being surpassed at the end. The second trial
of palm mulch surpassed the growth the first
mixed trial at the end of collection as well
(Figure 6).
The findings that coffee produces the
highest yield, contradicts the original
Figure 6. Above-The overall growth rates
averaged among the two trials. Below- Trial 1
is represented solid lines and Trial 2 with
dashed lines.
Discussion
Contrary to the original hypothesis
that the mixture of palm mulch, oak mulch,
and coffee grounds would colonize at the
fastest rate, the coffee grounds used as a
substrate gave the quickest colonization
times. The mixed substrate had the second
quickest colonization, the palm mulch came
7
in a close third, and oak mulch mycelium
growth never surpassed 20% growth. As a
result of this, it is believed that by oak
mulch being in the mixture, it may have
decreased the nutritional value of it enough
to put it at a disadvantage when compared to
coffee alone, which is extremely nutrient
rich. If not the nutritional value, then the
high density of oak mulch pieces may have
been the culprit for the slow rate of
mycelium growth. While mushrooms are
one of the few things able to break down
lignin, a very complex polymer found in
wood, it can cause growth to be a much
slower process as the nutrients are not as
easily accessible as in other substrates, ie.
coffee (Buswell & Odier, 1987).
Although coffee had the quickest
colonization rates, it was later determined
that the mixed substrate is the most
sustainable because of coffee’s vulnerability
to environmental factors. Despite proper
pasteurization techniques, the nutrient
richness of coffee attracted other types of
fungi and some jars were contaminated. This
was visible through a green mold growing
throughout 3 of the jars. Contamination such
as this would be detrimental to mushroom
growers. In Pennsylvania in the 1990s, the
mushroom industry experienced losses of
between 30-100% as a result of this mold
(Tisdale, 2004). Coffee was also determined
to be less stable than the other substrates. At
one point late in the experiment, the
humidifier stopped for a brief period of time
(approximately 5 hours), which caused the
coffee substrate pull away from the sides of
the jar and mushrooms to slightly shrivel,
whereas the other substrates remained
stable. Coffee’s inability to maintain
moisture content would be unfavorable in
larger outdoor experiments that could
potentially be faced with periods of drought
and flood.
Due to time constraints of the
project, the experimental data was collected
before fruiting bodies emerged. Therefore,
instead of determining the efficiency
substrates by comparing mushroom mass,
the mycelium growth was analyzed. As a
result of this, there may be some bias in the
mycelium growth results reported as they
were based on outward visual appearance,
and inner growth in the jars could not be
properly accounted for. This was discovered
after the appearance of mushrooms in all of
the jars. These results were unexpected,
especially in the case of oak mulch, where
barely any mycelium growth had been
observed. It is believed that even though the
mycelium growth may not have been
visible, it was still occurring in the middle of
the substrate, where it was not visible. It is
possible this is due to the density differences
among the substrates, something like coffee
grounds having a very low density and being
easy to maneuver through, compared to
chunks of oak mulch being hard to break
apart.
Figure 7. Mushrooms growing on the coffee
substrate.
Mushrooms started to appear only a
few days after the experimental cut off
point, and shocking observations were
reported. Even the oak mulch, which
visually had the least mycelium growth
produced mushrooms. A future experiment
analyzing the mass of fruiting bodies will
8
provide more information about the
effectiveness of growing on each substrate.
As far as measuring the percentage
of substrate converted to compost,
mushrooms grow as they decompose more
and absorb more from their substrate. As a
result of this, it is reasonable that the larger
the mushrooms are, the more the soil has
been broken down into compost. Based off
of these results, both coffee and the mixed
substrates were composted the most, as they
produced
the
largest
mushrooms,
presumably from degrading the soil at a
higher rate. If removal of waste is the main
focus of future growers, then mixed
substrate would be the best option as it
allows for conversion of three types of waste
into compost rather than just one.
This can cycle back into the concept
of sustainability. By using the spent
substrates, they can then be composted and
eventually converted into compost to add
nutrients back into the soil. Coffee grounds
are especially a readily available source of
“waste”, which is highly beneficial to the
process and will allow for a continuous
supply of substrate to produce at high yields
for the community.
Some may see placing all jars in the
same terrarium as another possible bias in
this experiment; however, even if spores
transfer substrates during the cultivation
period, the spores will not have enough time
to develop into fruiting bodies and will
therefore not affect the final mass, creating
no experimental bias. Also, there is no need
to worry about cross contamination of
species since all of the spawn used across
the various substrates will be one consistent
species, Pleurotus Djamor.
Future Work
The findings of this experiment have
led to further questions being asked. After
discovering that coffee rather than mixed
grew the fastest, possibly being due to high
lignin content/high density or low nutritional
value of oak mulch in the mix, the
experiment was rethought out. The
experiment should be repeated in the future
with a mix of coffee and palm alone.
Predicted results from this experiment are
shown in Figure 8.
Figure 8. Previous experiment results along
with predicted results for a palm and coffee
mixture (dashed line).
In theory, the combination of palm
and coffee without oak will be the best
combination of the three. This is because the
palm much should decrease the risk of
contamination as it will just slightly lower
the richness of the coffee. Additionally, the
oak mulch will not be an obstacle for
mycelia growth. As well, by using a
combination of two of the three rather than
one alone, more waste will be able to be
composted.
9
An additional issue in this
experiment was finding the exact moisture
content of the substrates in the beginning.
Eventually, the oven method was decided
on, but even though this was the most
precise method found, it was still not exact.
While pasteurizing the substrates in the
oven, some moisture tended to escape
through the lids of the containers, so the
final exact moisture content was most likely
1-5% off of what it had prior to this process.
September 26, 2013, from
http://www.bbc.co.uk/schools/gcsebitesize
/geography/wasting_resources/waste_poll
ution_rev1.shtml
Blume, L. (n.d.). Linear models of
production. Informally published
manuscript, Cornell University & The
Santa Fe Institute & IHS, Ithaca, NY,
http://elaine.ihs.ac.at/~blume/LinearModel
s.pdf.
As a result, a further experiment is
planned in which autoclavable bags will be
filled with dried substrates (0% moisture
content) to start. The amount will be
weighed and 65% water will be added to the
bags. The bags will then be sealed shut and
autoclaved.
This
process
should
theoretically cause the water within the bags
to steam the substrate throughout, thus
creating a completely uniform moisture
content within the bags. The substrates
should then give more consistent results.
Bressa, G., L. Cima & P. Costa. 1988.
Bioaccumulation of Hg in the mushroom
Pleurotus ostreatus. Ecotoxicology and
Environmental Safety Oct. 16(2), 85-89
Acknowledgements
Campbell, Neil A., and Jane B. Reece. 2011.
Biology. San Francisco, CA. Benjamin
Cummings. Print. 636-652.
This experiment would not have
been possible without the UCF Arboretum
and local coffee shops supplying the
substrates. As well, huge thanks go to
Jennifer Elliott and Alaina Bernard for
guiding us through this project and for
providing the opportunity for educational
community outreach.
References
Anoliefo, G.O, O.S. Isikhuemhen, & E.C.
Okosolo. 1999. Traditional coping
mechanisms and environmental
sustainability strategies in Nnewi. J Agric
Environ Ethics 11, 101–109
Buswell, J.A. & Odier, O. 1987. Lignin
biodegradation. Critical Review of
Biotechnology 6, 1-60.
Callicott J (1997). Conservation Biology.
Ecological Sustainability as a
Conservation Concept. 11(1), 32-40.
Dundar, A. & Yildiz, A. 2008. A
Comparative Study on Pleurotus
ostreatus(Jacq.) P.Kumm. Cultivated on
Different Agricultural Lignocellulosic
Wastes. Tubitak. 33, 171-179.
Leonard, A. (2007). The story of stuff: The
impact of overconsumption on the planet,
our communities, and our health-and how
we can make it better. Simon and Schuster
Retrieved from http://www.hebel.arch.
ethz.ch/wp-content/uploads/2012/08/TheStory-of-Stuff.pdf
BBC - GCSE Bitesize: Global waste
production. 2013. BBC. Retrieved
10
Kalita, P. & Mazumder, N. 2001.
Performance of oyster mushroom
(Plerotus spp.) on certain plant wastes.
Journal of Agricultural Science Society of
North-East India 14, 221-224.
Rinker, D.L. 2002. Handling and using
“spent” mushroom substrate around the
world. In: Sánchez JE, Huerta G, Montiel
E (eds) Mushroom biology and mushroom
products. Impresos Júpiter, Cuernavaca.
43–60.
Rizki, M. & T. Yutaka. 2011. Effects of
Different Nitrogen Rich Substrates and
their combination to the yield performance
of Oyster Mushroom (Pleurotus
Ostreatus). World J. Microbiol Biotechnol.
27, 1695-1702.
Stamets, P. 1999. Earth’s natural Internet.
Whole Earth Review, Fall. 74-77.
Stamets, P. 2000. Growing Gourmet and
Medicinal Mushrooms. Berkeley, CA: Ten
Speed. Print. 282-300.
Thorn, R.G. & G.L. Barron. 1984.
Carnivorous mushrooms. Science. 224,
76-78.
Tisdale, T. E. 2004. Cultivation of the
Oyster Mushroom (Pleurotus sp.)on Wood
Substrates in Hawaii. Thesis, University of
Hawaii. Retreived from
http://scholarspace.manoa.hawaii.edu/
bitstream/handle/10125/10549/uhm_ms
_3935_r.pdf?sequence=1
11
Research Proposal
The Effect of Soil Conditions on Plant Health at the University of Central Florida
BSC 4861L
12/7/2013
Jacqueline Gibson
Diana Bateman
Phillip Ten Eyck
Paul Ruben
The Effect of Soil Conditions on Plant Health at the University of Central Florida
1. Introduction
When choosing a university, prospective students hope to be surrounded by a
flourishing and healthy environment. Boyer (1987) of The Carnegie Foundation suggests,
“The appearance of campus is, by far, the most influential characteristic during campus
visits.” Studies have even suggested that regular exposure to natural environments could
aid in the prevention of certain public health issues, such as mental ill health (Maller et al.
2005). As of 2010, the University of Central Florida was the second largest university
with more than 56,000 enrolled students, and has still grown in recent years (UCF Today
2010). With this growth, the development of new buildings, parking garages, and housing
has called for better landscaping on-campus, as well as increased consideration of how
the campus affects surrounding natural lands and on-campus natural resources.
Urban environments have drastically changed the composition of natural
ecosystems, particularly in recent years. Living soils are vulnerable to rapid changes but
serve as good indicators of ecological health (Xiao-Lin Sun 2012). Soils within urban
environments are susceptible to abnormal compaction. By reducing the ability of water
infiltration within soils, severe compaction can increase the amount of run-off of
pollutants and synthetic fertilizers. Local ecosystems are directly affected by this
development. Sandy soils have a higher infiltration rate and are more susceptible to
nutrient leaching (Nguyen and Marschner, 2013).
1.1. Soil conditions
Soil compaction is compression of particles leading to the reduction in the amount
of pore space. Infiltration is the process by which water is absorbed into soil. Soil
moisture is the amount of water saturation used for uptake by plants. The measure of a
2
The Effect of Soil Conditions on Plant Health at the University of Central Florida
soil’s acidity or alkalinity indicates pH value. Soil types are determined by composition
and grain size of dried soil (sandy, organic, mixed, etc.)
Soil compaction is common in urban environments due to heavy pedestrian and
motor vehicle traffic. Compaction may promote or harm plant health, the latter occurring
more frequently (Kozlowski 1999). High compaction increases the degree of overflow
and runoff of pesticides, herbicides, heavy metals, and excess nutrients (Olson et al.
2012). Subsoil is more vulnerable to compaction in areas of construction where topsoil
was removed. Roots struggle to penetrate compacted soil, which limits their range.
Infiltration of soil is important for plant roots to receive proper water uptake. Soils that
are aerated and comprised of compost have higher rates of water infiltration (Olson et al.
2012). Organic soils are more likely to display these attributes and are more conducive to
plant growth. Sandy soils, on the other hand, drain quickly and have difficulty retaining
nutrients. Central Florida’s native soil type is Myakka, which is comprised of a sandy
topsoil and partially organic subsoil (USDA 2011).
Urban landscapes generally lead to increasingly acidic topsoil. Xiao-Lin Sun
(2012) states that on average pH decreases by 0.9-1.02 over the span of many decades in
unintentionally pH manipulated urban environments. While a decreasing pH can favor
plants adapted to acidic conditions, such changes could lead to an increase of invasive
species. The coevolution of plants and their specific environment suggests a need to
understand the pH parameters in which they may survive.
1.2. Plant health
For this study, plant health is defined as the ability to perform normal biological
functions, such as the ability to maintain healthy leaf color and structure with minimal
3
The Effect of Soil Conditions on Plant Health at the University of Central Florida
signs of stress or disease. Döring (2012) suggests, “A plant can be regarded as healthy as
long as its physiological performance, determined by its genetic potential and
environmental conditions, is maintained.” Essential nutrients, such as nitrogen,
phosphorous, and potassium (N-P-K) are derived from abiotic conditions, such as water
and air. Nitrogen is important for all plant functions due to the major role it plays in
building amino acids and chlorophyll production. Phosphorous is an energy source (ATP)
during photosynthesis and important for DNA and RNA production. Potassium controls
water uptake (stomata) and deficiencies are indicated by abnormal plant shape and color
(Markham, 2010).
The effective ecological management of plants and their optimal soil conditions
could help to maintain an aesthetically pleasing urban setting. In order to understand
these biological conditions and how urbanization is affecting urban soil, fieldwork is
needed to test specific soil types, compaction, and infiltration. This data can be used to
make recommendations to maximize plant health in a variety of soil conditions.
1.3. Objectives and Hypothesis
This project evaluated plant beds for conditions that influence plant health and
made recommendations to improve plant fitness and overall appearance at the University
of Central Florida. We anticipated that soil compaction and infiltration would affect plant
health. We also predicted that soil type would influence the content of macronutrients (NP-K) and plant health.
2. Materials and Methods
There are four irrigation computer control units (CCU) on campus. Forty-four
random sample sites, 11 in each unit, were selected for the study. Random sampling let us
4
The Effect of Soil Conditions on Plant Health at the University of Central Florida
make conclusions for the entire campus. Using ArcGIS, a program for managing
geographic data, points were plotted and arranged for collection. Locations were
observed and classified as predominantly organic, sandy, a mix of organic and sandy, or
construction rubble as a soil type. Soil types were distinguished by grain size. Large
grains were classified as sandy and small were considered organic. Any signs of disease
or abnormalities on the plants, including rigidity, were recorded for each planting bed.
We observed plant health and took photographs that were evaluated by a local plant
expert on a scale of 1 to 5. Clear signs of disease, parasitism, discoloration, structural
weakness and little growth were given a plant health of 1. Plant beds with the absence of
disease and all other factors were given a health of 5. The study was focused
predominantly on ornamental plants and subcanopy. Randomly occurring invasive plants
and mature canopies were not included in the plant health scale. A golf cart was used to
find each planting bed.
The infiltrometer was inserted in an open location within a plant bed two feet
from all plant bases. Mulch and debris were removed from the infiltration site to not skew
results by blocking water flow. The device was filled with de-ionized water to avoid ion
contaminants. We conducted a test to moisten the soil and then re-filled the device for
data collection. The infiltrometer was set at fifteen minutes for each plot and was stopped
when water reached three inches. Simultaneously, soil moisture and pH were tested away
from the infiltrometer to avoid added water. The pH was measured from 3.5 to 8. A soil
compaction test was used at depths of 3 and 6 inches into the ground. The compaction
tester had a scale of 0 to 300+ (units not specified). One researcher would conduct the
compaction experiment while the other would spot the device’s depth. A core-sampling
5
The Effect of Soil Conditions on Plant Health at the University of Central Florida
device was used to take samples for each soil type. Samples were taken from each bed
and distributed over a plastic wrap to dry. Any debris, such as sticks and rocks were
removed from the sample. The soil samples were tested for levels of nitrogen,
phosphorus and potassium (macronutrients).
3. Results
Of the 44 campus plots there were seven that were organic soil, twenty-one that
were sandy and sixteen of a mixed soil type. The sandy soil had more nutrients on
average than the mixed or organic soil as shown in Figure 1. The mixed soil had the
second most nutrients overall and the organic had the least on average.
Average Macronutrients
Macronutrients in Relation to Plant
Health
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
5
4
3
2
1
Mixed
Organic
Soil Type
Sandy
0
Nitrogen
Phosphorous
Potassium
Plant Health
Figure 1. Macronutrients in relation to plant health.
Data for the pH readings and moisture were questionable. We did not find results
for moisture and pH because we believe the meter to be inaccurate. The expert we
consulted used a scale of 1-5 to evaluate plant health with 5 being healthier than 1. The
organic soil had the highest plant health of the three soil types. There were two plots that
6
The Effect of Soil Conditions on Plant Health at the University of Central Florida
had a plant health rating of 1. Three plots had a plant health of 2 and nine were rated 3.
The majority were rated 4 and 5 with 14 and 16 respectively (see Table 1).
Table 1. The number of plots per each plant health rating, 1-5.
Plant
The
Health
number
Scale
of plots
1
2
2
3
3
9
4
14
5
16
The average infiltration was 53.83 inches per hour, with sandy soil having the
highest infiltration rate. The average infiltration for mixed soil was 42.34 in/hr, organic
soil was 48.48 in/hr, and sandy soil was 64.31 in/hr as per Figure 3.
Infiltration (in/hr)
450
Infiltration in Relation to Plant Health
0
400
1
350
300
2
250
3
200
150
4
100
50
0
5
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43
Plot Number
Infiltration
(inches/hr)
Plant Health
6
Figure 2. Infiltration in relation to Plant Health
7
The Effect of Soil Conditions on Plant Health at the University of Central Florida
Average Infiltration
Infiltration by Soil Type
70
60
50
40
30
20
10
0
Mixed
Organic
Soil Type
Sandy
Figure 3. Average Infiltration by Soil Type.
The average compaction for a depth of 3 inches was 86.36 ± 30.85. The average
compaction for a depth of 6 inches was 158.86 ± 67.57. The compaction meter did not
have a unit specified but a scale from 0-300+ with three levels. From 0-199 is considered
a green compaction zone that is good for most plant growth. 200-299 is considered a
yellow compaction zone and decent for most plants growth. 300+ is considered a red
compaction zone that is poor for plant growth. In Table 2, the greatest percentage of
plots, 31%, had compaction zones of less than 200 and plant health ratings of 5. Plots
rated with a health of 4 had the second highest green compaction zone (20%). Only 4%
of the plots were considered in the red zone with 300+ compaction.
8
The Effect of Soil Conditions on Plant Health at the University of Central Florida
Table 2. Comparing the number of plots in each compaction zone to their health level.
Compaction zone
Plant
health
Green
Yellow Red
5
0.32
0.02
0.02
4
0.20
0.09
0.02
3
0.07
0.14
0
2
0.05
0.02
0
1
0.05
0
0
The F-test for the infiltration was significant with a p-value of 1.80213e-65. A one
tailed T-test with two sample unequal variances was also significant with a p-value of
1.54693e-05.
The p-values that were closer to zero and did not correlated above 0.1 or higher
are significant. The compaction at 3 inches F-test p-value was significant as shown in
Table 3.
Table 3. The F-tests and T-test results regarding infiltration and compaction for all plots
F-test
T-test one tail, two sample unequal variances
Infiltration
1.80213E-65
1.54693E-05
Compaction at 3 in
1.47192E-50
1.02576E-21
Compaction at 6 in
3.49157E-65
3.21102E-19
4. Discussion
This study demonstrated that soil conditions such as soil type and compaction
were indicators of plant health in an urban environment. The majority of plots were
9
The Effect of Soil Conditions on Plant Health at the University of Central Florida
shown healthy with only a few affected by these conditions Table 1. Organic soil had
higher plant health but lower overall macronutrients than sandy and mixed soil types
Figure 1. This may be due to the higher abundance of sandy soil types found on campus
or fertilization by faculty prior to the study. Sandy soil types had the most macronutrients
(Figure 1), which was an unexpected result. We predict this may be because of the
higher abundance of planting beds with sandy soil types found on campus.
All of the plots were in the green compaction zone (0-200) at 3 inches. This meant
that the immediate topsoil was not highly compressed. Plots 3, 11, and 22 had a higher
compaction at 3 inches than at 6 inches, indicating a dense and healthy root structure. A
plant health of 5 was determined for all 3 beds. Plots with a maximum plant health of 5
had the most plant beds in the green compaction zone (32%), with only one highly
compacted plot at 6 inches. Plants with a health of 4 had the second most in the green
compaction zone (20%) Table 2.
There were no observable correlations between infiltration and plant health,
although our p-value was significant (1.80213E-65) Figure 2. Infiltration was most
common for sandy soil types (64.31 in/hr) and decreased from organic to mixed soils
Figure 3. This followed our prediction of sandy soil types and their ability to rapidly
infiltrate.
A total of thirty-nine ornamental plants were analyzed in the study. Five of these
plants occurred more than twice. Indian Hawthorn (Rhaphiolepsis indica) appeared in ten
plant beds. Only one plot 15 (construction rubble) had the slowest rate of infiltration (4
inches/hour) and a high compaction (100/375 inches). Unhealthy plants suffered from sun
damage, fungus, herbivory, and excessive moisture. Layers of mulch were common
10
The Effect of Soil Conditions on Plant Health at the University of Central Florida
above sandy soil medium, which retained moisture and decreased plant matter
decomposition. Dollarweed (Hydrocotyle spp.) and Balsampear (Momordica charantia)
were two common invasive plants found in plant beds.
Soil amendments may be performed to increase aeration, decomposition of mulch,
and reduce compaction to improve plant bed conditions. A core aerator can be used to
manually amend compaction in plant beds. The addition of native sandy soil may
increase infiltration in severely compacted beds. We faced a few problems during the
time of our research. The infiltrometer does not accurately mimic the variations of natural
rainfall. Filling a cup with water does not measure the velocity of rain occurring from
clouds. Distilled water was used instead of de-ionized for the first three weeks of
research. We adjusted to the nearest possible plant bed when plots were unavailable to
locate. We did not take pictures of the gradient of soil types for core samples. This may
have been beneficial to note in our analysis. The moisture readings were inconsistent with
observable soil conditions. A different device would be encouraged if replicated. Future
studies can be conducted to focus on specific plant species that do well in a wide range of
conditions.
11
The Effect of Soil Conditions on Plant Health at the University of Central Florida
Literature Cited
Boyer, E. (1987). College: The undergraduate experience in America. New York: Harper &
Row, Publishers.
Campus Landscapes. (2013). UCF Landscape and Natural Resources [Internet]. [cited 2013
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Döring, T. F., M. Pautasso, M.R. Finckh, and M.S. Wolfe (2012). Concepts of plant health–
reviewing and challenging the foundations of plant protection. Plant Pathology, 61(1), 115.
Kozlowski, T. T. (1999). Soil compaction and growth of woody plants. Scandinavian Journal
of Forest Research, 14(6), 596-619.
Lewis, KJ. (November 3, 2010). Quality Growth: UCF is Nation’s Second Largest. UCF
Today [Internet]. [cited 2013 Sept 27]; Available from: http://today.ucf.edu/qualitygrowth-ucf-is-nations-second-largest/
Maller, C., Townsend, M., Pryor, A., Brown, P., & St Leger, L. (2006). Healthy nature
healthy people:‘contact with nature’as an upstream health promotion intervention for
populations. Health promotion international, 21(1), 45-54.
Markham B.L. 2010. Mini Farming: Self-Sufficiency on ¼ Acre. Skyhorse Publishing. 62-63
p.
Olson N.C., J.S. Gulliver, J.L. Niber, and M. Kayhanian. 2012. Remediation to improve
infiltration into compact soils. Journal of Environmental Management. 117(2013) pp.
220-230.
Pereira B.F.F., Z.L. He, M.S. Silva, U. Herpin, S.F. Noqueira, C.R. Montes, and A.J. Melfi.
(2011). Reclaimed wastewater: Impact on soil-land system under tropical conditions.
Journal of Hazardous Materials 192.
Xiao-Lin Sun, Sheng-Chun Wu, Hui-Li Wang, Yu-Guo Zhao, Gan-Lin Zhang, Yu Bon Man,
and Ming Hung Wong. 2012. Dealing with Spatial outliers and mapping uncertainty for
evaluating the effects of soil: A case study of soil pH and particle fractions in Hong
Kong. Geoderma. [updated 22 November 2012, cited 27 September 2013]. Available
from: http://www.sciencedirect.com/science/article/pii/S0016706112004132
12
The Effect of Soil Conditions on Plant Health at the University of Central Florida
13
Summary UFORE Study The UFORE (Urban Forest Effect Model) Study is designed to allow cities or institutions to calculate the total value of atmospheric carbon (CO2) and pollutant (CO, NO2, O3, PM10, SO2) removal by the vegetation present in the study area. This information can be used to calculate the baseline carbon sequestration rate; used for institutions endeavoring towards carbon neutrality and sustainability; and total atmospheric noxious gas removal. UCF has pledged to become carbon neutral by 2025, and gathering accurate information on the natural rate of carbon removal by campus vegetation is essential in projecting the lowest rate of carbon release possible from all campus consumption activities. The total surveyed area covered 1.93ha in a total of data 45 plots. This was a representative sample of the total area of UCF main campus and McKay Tract Conservation Easement. The study collected data on 296 trees (29 species), comprising at total of 18.1% tree canopy cover. The total estimated value of these trees is $42,050 USD based on energy savings from shaded buildings heating/cooling costs. In total, all trees and shrubs together store approximately 14.9 tons of carbon and sequester another 1 ton per year, removing 48.9kg/yr of pollutants. Of the 10 most abundant tree species, longleaf pine, snad live oak, dahoon holly and slash pine are responsible for the majority of pollution/carbon removal and storage. Vacant and wetland forest areas show the highest level of storage/sequestration per unit area in total and contain much of the leaf biomass observed. Upland forests account for the highest level of carbon storage/sequestration in total but are at stable phases of growth so they don’t show the highest level per unit area. 10 most abundant species (% of total)
10 most abundant leaf biomass species (% of total)
20
15
15
10
10
5
5
0
0
Carbon storage (kg)
8
7
6
5
4
3
2
1
0
Carbon storage per area (tons/ha)
16
14
12
10
8
6
4
2
0
Project Proposal I.
Title: Sustainable Urban Gardening II.
Authors: Damon Braun, Troy Maxwell, Melissa Paduani, Angie Spiva, Katrina Tecxidor, & Mindy Yang III.
Introduction: The implementation of soil amendments in agricultural systems is a common and universal practice utilized to increase product yield, decrease the time to harvesting, and feed a perpetually growing population. These amendments include varieties of fertilizers and composts, both of which come in organic and synthetic forms. They are useful because of their nutrient content, most often providing supplementary amounts of nitrogen, phosphorous, and potassium. Other enhancement products applied to natural and agricultural systems are pesticides and herbicides, which are useful in maintaining crop cultures and protecting them from pests. These chemicals may be of great utility in achieving desirable aesthetics, increased agricultural yield, and for pest control, however, these enrichment products can have costly effects on the surrounding environment. One result of fertilizer use is storm­water runoff, which is the product of a storm event carrying accumulated pollutants from impervious surfaces into detention ponds, streams, and other connecting bodies of water. The accumulation of materials in aquatic systems threatens biodiversity and ecosystem function with eutrophication, habitat loss, and decreased availability of dissolved oxygen (Taylor et al., 2005). The pollutants can also make their way into terrestrial systems. Common sources of these pollutants include pesticides, herbicides, and fertilizers that are applied to the environment (Sharpley et al., 1994). Fertilizers and composts in particular are the primary sources of runoff material that includes nitrogen, phosphorous, and potassium. These soil amendments are also related to issues involving nutrients leaching into the environment (Broschat, 1995). When a storm event occurs, the precipitation that permeates the soil can carry leached nutrients from agricultural systems and direct them into the larger watershed. This poses threats to water quality, ecosystem function, and soil composition. The process by which excess nutrients and pollutants enter the environment is also facilitated by the urbanization of natural areas, leading to increased metropolitan development that will encroach and hinder biological ecosystems. In order to reduce harmful runoff and meet the needs of large populations, sustainable urban gardening becomes a useful model to implement. The methodology behind sustainable gardening within urban settings is specifically necessary in the context of large metropolitan universities. The University of Central Florida (UCF) hosts over 60,000 students on its multiple campuses. Many of these students live in dorms or on­campus housing for their first and second years. A common scenario for many of these students is difficulty in maintaining a balanced diet, and having accessibility to fresh produce. Restricted diets and constrained availability of healthy foods limits students’ potential to perform academically and feel physically, mentally, and spiritually well. In order to address the major concerns of sustainable urban gardening, our study is being conducted to deduce: 1) how to reduce nutrient leaching and runoff while maximizing plant growth and 2) what to grow in urban agricultural systems that will feed as many students as possible at UCF while keeping in mind the types of vegetables students will like to eat. Our study will focus on four compost types: organic, synthetic, mushroom, and Orange County yard waste. IV.
Materials / Methods: A. Materials: 1. Compost Type a) Orange County: Yard waste, plant material b) Organic: Store­bought amendment, organic matter c) Mushroom compost d) Synthetic: Store­bought synthetic fertilizer 2. Edible seedling variety­ selection based on seasonality a) Tomato b) Kale c) Lettuce 3. 8­12 inch diameter pots [~40 total including control] 4. Water collection trays 5. Chemical composition testing materials a) Nitrogen b) Phosphorus c) Potassium d) pH B. Methods: The experiment will be conducted at the University of Central Florida within the parameters and supervision of the campus Arboretum. The experiment will begin the first week of October and last for 6 weeks. Seasonality will affect plant growth, therefore the seeds chosen will be mild­moderate freeze tolerant species (Little et al., 2015). Edible plant species will be chosen based on their commonality and aptitude for future harvesting. The common tomato (​
Solanum lycopersicum​
), kale (​
Brassica oleracea)​
,​
and lettuce​
(​
Lactuca sativa​
)​
seedlings will be measured as well as the chemical composition of the specific compost/substrate that they are individually planted in. To measure the differing effects of compost on seedling development and nutrient leaching, individual compost components will be labeled in an 8­12 inch diameter pot. One seed from one species will be planted into a pot that contains one type of compost/substrate with three replicates for each individual compost type and seedling type per watering collection tray. A control will be used that contains each compost type and will measure nutrient leaching without the presence of the singular seedling. Results from water testing will be recorded 1­3x per week. Nitrogen, phosphorus, potassium, and pH will be measured from each tray containing the three replicates after watering. The same amount of water will be used during each session and will be repeated amongst all potted replicates per water collection tray. Seedling height and width will also be recorded once sprouting occurs. At the end of the 6­week experiment, seedlings will be removed from their respective pots, cleaned from compost/substrate, and their root length and weight will be recorded. V.
Anticipated Results: We anticipate that each of our chosen fertilizer types will leach nutrients to some degree and effect the growth of our plants in different ways. Based on our research we suspect nutrient leaching to be at its highest levels when fertilizer is applied to the soil initially, when our plants are small seedlings, and require less nutrition (Kiggundu, 2012). Our research also indicates that synthetic and manure fertilizer composts are the best at yielding larger plant growth. Synthetic fertilizers have been observed in other studies to leach more nutrients into the environment, thereby potentially putting pollutants into the water supply, and the environment. Because of this we also believe that manure composts, or some combination with manure compost, will overall be the most efficient in producing the most yield with the least amount of nutrient leaching. After we determine the most efficient means of growing our plants the second part of our experiment will be to determine the best location to grow on a massive scale at UCF, as well as determine a plan to accomplish this economically. Labor involvement will also be a factor. We anticipate that students could potentially provide the majority of the labor associated with the large scale crop growth on campus. Extending the Arboretum to include more areas to grow vegetables then it currently can hold is an option, however a larger plot of land may prove to be better for growing on such a scale in the long run. We will determine the economic costs associated with this option as we go through our experiment. Some of the foreseen costs for such an endeavor can be reduced by recycling the food waste from on­campus restaurants, while also building a fully free scale system where all food on campus is either grown or recycled at some point in some way (Bond, 2013). Food waste is and will become more and more of an issue nationwide and in building a more sustainable food growth system we can help reduce some of this. It should be noted that this project also seeks to achieve greater connectivity among students at UCF. Growing food will bring together students from all walks of life, thus leading to a greater sense of community on campus, and more connections being made that could lead to more opportunities in the future. Growing sustainably will give students a sense of pride and will teach them tools that they can take with them to grow their own food at home, and in doing so save them money and potential harm from processed foods. VI.
References: Bond, M., Meacham, T., Bhunnoo, R., & Benton, T. (2013). Food waste within global food systems. Retrieved September 27, 2015, from http://www.foodsecurity.ac.uk/assets/pdfs/food­waste­report.pdf Broschat, T. K. (1995). Nitrate, phosphate, and potassium leaching from container­grown plants fertilized by several methods. HortScience, 30(1), 74­77. Kiggundu, N., Migliaccio, K., & Schaffer, B. (2012). Water savings, nutrient leaching, and fruit yield in a young avocado orchard as affected by irrigation and nutrient management. Retrieved September 27, 2015. Little, N., Mohler, C., Ketterings, Q., & Ditommaso, A. (2015). Effects of Organic Nutrient Amendments on Weed and Crop Growth. ​
Weed Science,​
710­722. Sharpley, A. N., Chapra, S. C., Wedepohl, R., Sims, J. T., Daniel, T. C., & Reddy, K. R. (1994). Managing agricultural phosphorus for protection of surface waters: Issues and options. Journal of Environmental Quality, 23(3), 437­451. Taylor, G. D., Fletcher, T. D., Wong, T. H., Breen, P. F., & Duncan, H. P. (2005). Nitrogen composition in urban runoff—implications for stormwater management. Water Research, 39(10), 1982­1989. Islands in the Sun: A
University of Central Florida
Urban Heat Island Study
Maria Crosby, Peter Denis, Keith Berry, Alexandra Schilling,
Christen Callahan
Abstract
Figure 1. Depiction of a thermal gradient caused by a typical
urban heat island.
The aim of this research is to scale down synoptically to the University of Central Florida’s
(UCF) main campus, to determine if there is an urban heat island (UHI) thermal gradient and
provide evidence that temperatures related to a UHI will decrease along a horizontal plane with
distance. The UCF main campus is a mixture of both urbanized and natural lands. Where the
urbanized land meets natural land, a temperature gradient should be detectable coming from
both directions. 24 Hobo Pro V2 data loggers were placed along four transects around UCF
with two additional data loggers placed in the urban and natural lands as controls. Each
transect was 400 meters long and 80 meters in between each logger. Data was collected for a
total of four consecutive weeks, logging temperatures every four hours. Average daily
temperatures recorded at data loggers along the entire transect showed high variability at all
times of day, except the hottest during the hours of 1200 and 1600. The urban control point
recorded higher average daily temperatures than the natural control at every time of day. We
failed to reject our hypothesis that UCF is a UHI because of the high urbanization, significant
differences in daily average temperatures between urban and natural areas. There were
significant differences in ability to process heat between urban and natural areas. These are all
indicators that suggest that there is a UHI.
Introduction
One of the biggest impacts to the
environment is climate modifications due to
urbanization by a rapidly growing global
population. According to the World Health
Organization, 54% of the global population
resides in urbanized areas.1 Population
growth in urban regions increased 12% from
1960 to 2014 and is projected to increase to
well over 6 billion worldwide by 2045.2
Increased populations will raise the
demand for the expansion of urbanized areas
in order to accommodate basic needs. These
needs include shelter, transportation,
employment, and education vectors. As a
result, this leads to the construction of more
buildings and paved areas, at the expense of
deforestation of natural lands.
The transformation of natural lands
to accommodate increased urbanized areas
causes significant land changes which
impact local weather patterns, human health,
and ecosystem functions.3 The reduction of
1
http://www.un.org/en/development/desa/news/population/w
orld-urbanization-prospects-2014.html
3 Imhoff, M.L., P. Zhang, R.E. Wolfe, and et al. (2010).
Remote sensing of the urban heat island effect across
biomes in the continental USA. Remote Sensing of the
Environment, 114, 504-513. DOI:
10.1016/j.rse.2009.10.008
World Health Organization. (2014). Urban Population
Growth. Growth Health Observatory. Retrieved from:
http://www.who.int/gho/urban_health/situation_trends/urba
n_population_growth_text/en/
2 The Department of Economic and Social Affairs. (2014).
World’s population increasingly urban with more than half
living in urban areas. Retrieved from:
vegetation coupled with impervious surface
area, as well as, building morphology in
urban centers combine to decrease
evapotranspiration, increase heat storage and
warm the surface air.4 Urbanized areas
without ecosystem sustainability measures
in place cause ambient air temperatures to
be higher than surrounding natural lands.
When differences in temperatures from
these areas occur, it said to be a UHI.2
Urban heat islands play a role in
socio-economics by increasing the number
of degree cooling days for consumers, which
in sub-tropical areas, will lead to increased
cooling costs. The resulting rise in normal
air temperatures as a result, impact human
health more than any extreme weather
form.5 These health impacts can often affect
the lower social class, whereas, the
operating costs of air conditioning cannot be
met. In areas of higher socioeconomics
reduction strategies in terms of landscape
vegetation is more pronounced than in lower
income neighborhoods.5
Increased cooling demands also
increase power plant emissions, adding to an
already polluted atmosphere. In areas that
lack sustainability measures to counteract
urbanization changes, air quality is
compromised by changing emissions and
altering the state of the atmosphere.4 These
alterations can lead to thermally induced
thunder Akbari, H. (2005). Energy Saving Potentials and
Air
Quality
Benefits
of
Urban
Heat
IslandMitigation. Lawrence Berkeley National Laboratory.
activity altering local climate.
Urban heat islands increase air
pollution
and
disrupt
neighboring
ecosystems with storm water run-off. Water
quantity and quality is compromised
adversely affecting aquatic species and the
integrity of watersheds. Stormwater is
polluted as it flows over impervious surfaces
picking up non-point source pollution such
as gasoline, petroleum, oils, and other
environmentally toxic chemicals.6
In terms of human health impacts,
urban heat islands contribute to heat
conditions in the human body and increases
infectious disease risks.7 These heat
conditions include syncope, heat stress, heat
stroke, heat cramps, and heat exhaustion.
Those
affected
by
the
increased
temperatures of urbanization include the
elderly and young, those with a certain
illness, or taking particular medications, as
well as, social status.6
When solar energy enters the
atmosphere and reaches areas of vegetation,
energy is absorbed to be used in the process
of photosynthesis. Excess energy is released
in the form of latent heat, which aids in
cooling. In contrast, man-made (synthetic)
material, such as buildings, parking lots, and
sidewalks absorb energy, but have no way of
processing it, and re-emit radiation back into
the atmosphere as long wave radiation in the
form of heat, decreasing cooling rates of
surrounding air. The cooling rate differences
will create a temperature distinction between
urban and natural areas, with the most
significant change in temperature occurring
along a boundary of where UHI influences
are not occurring.
Research methods concerning the
identification of urban heat islands have
used remote sensing since the early 1970’s,
as well as, fixed and transverse methods. In
looking at urban centers, it is important to
understand that there are three urban layers.
4
Foley, J., R.Defries, G.P. Asner, and et al. (2005). Global
consequences of land use. Science (New York, N.Y.),
309(5734), 570–4. DOI: 1126/science.1111772
5
Golden, Jay. (2004). The Built Environment Induced
Urban Heat Island Effect in Rapidly Urbanizing Arid
Regions-A Sustainable Urban Engineering Complexity.
Environmental Sciences. Vol. 00:0 000-000. 6
Frumkin, H. (2002). Urban Sprawl and Public Health,
117(June), 201–217.
7 Yow, D.M. G.J. Carbone. (2006).The Urban Heat Island
and Local Temperature Variations in Orlando, Florida.
Southeastern Geographer, 46(6), 297-321. DOI:
10.1353/sgo.2006.0033
The surface layer which generates a
surface urban heat island is concerned with
the temperatures of surfaces and primarily
utilizes indirect measuring by remote
thermal sensing. The Upper Boundary Layer
(UBL) is the area above roof area and
extends vertically to the point where
landscapes no longer influence the
atmosphere. The UBL is looked at on a
mesoscale level and typically measures
pollutants caused by anthropogenic heat
sources. The third layer is the urban canopy
layer (UCL) and is the most common
measured heat island. UCL is the area from
the ground to the average building height.8
Measuring of the UHI, UCL employs fixed
point and traverse methods. The UCL is on a
micro-scale level versus a macro-scale as
seen with the UBL.
Studies concerning the UCL
predominantly focus on the urban core and
UHI impacts to human existence, as well as,
the influence increased temperatures have
on climate. Very little research has been
conducted that specifically addresses the
horizontal extent at the surface of the UHI in
terms of how far it extends into natural
lands.
For the purpose of this research, a
fixed point method will be employed
utilizing standard meteorological measuring
heights. Recommended height placement of
instrumentation used to gather data is
unanimous across studies to be in the range
of 1.2 meters to 1.8 meters. By collecting
and analyzing urban and natural temperature
data over time, a confirmed UHI analysis
will yield a graph similar to (Figure 1).9
8
Voogt, J. ., & Oke, T. . (2003). Thermal remote sensing of
urban climates. Remote Sensing of Environment, 86(3),
370–384. doi:10.1016/S0034-4257(03)00079-8
9 Anwar, F. J. Khurshid. (2013). Urban heat island effect: Is
Karachi heating up while the countryside keeps its cool?.
The Express Tribune with the International New York
Times. Retrieved from: http://i1.tribune.com.pk/wpcontent/uploads/2013/08/595238-graph-1377459873-405640x480.JPG
Urban heat island studies of different
locations worldwide show variations in
when peak thermal differences occur.7 A
study conducted of Orlando, FL between
1999 and 2001 determined UHI effects to be
a phenomenon that typically occurred during
the night without interference from
atmospheric conditions.7 This study found
climatic conditions to play a significant role
in accurately determining a UHI. Weather
parameters such as cloud cover and wind
speed is found to impact data significantly.
Research concerning a UHI in
Orlando, FL, indicates that UHI intensities
(that is the strongest temperature
differences) did not occur if wind speeds
exceeded 5 m s-1 (11 mph).7 Cloud cover
will temper daily temperatures by causing a
reduction in heating of both urban and
natural areas rendering the data nonrepresentative of a UHI.7
Research has further shown that if
urbanized areas implement sustainability
measures it will help minimize and or
eliminate urban heat island surface
temperature anomalies. These efforts
include altering albedo of surfaces, sky view
factors, and amplification of cross air
ventilation.10 However, in areas without
sufficient sustainability measures, an urban
heat island can be identified utilizing
thermal gradients in select areas by fixed
point methods.10
These impacts can be reduced by
identifying an urban heat island and taking
measures to minimize those factors that
contribute to the rising surface temperatures
of urban centers. Some of these measures
include green roofs, appropriate surface
building material, plant canopies and urban
forestry, as well as, increasing the sky view
10
Weng, Q., D. Lu, and J. Schubring. (2004). Estimation of
land surface temperature-vegetation abundance for urban
heat island studies. Remote Sensing of Environment, 89,
467-483. DOI: 10.1016/j.rse.2003.11.005
factor and reducing harmful air pollutant
emissions.
The aim of this research is to scale
down synoptically to the UCF’s main
campus to determine if there is a UHI
thermal gradient and provide evidence that
temperatures related to a UHI will decrease
along a horizontal plane with distance. If
there is a thermal gradient at UCF’s main
campus the thermal map should reflect the
signature ‘island’ isothermic pattern (Figure
2) which is typical of a UHI.
Figure 2. Typical ‘island’ pattern of an Urban Heat Island.
Retrieved from:://thebritishgeographer.weebly.com/urbanclimates.html
Hypothesis
The UCF main campus is a heterogeneous
mixture of urbanized and natural lands.
Where urbanized land meets natural land, a
temperature gradient should be detectable in
both directions.
The first hypothesis tested if average
daily temperatures will decrease with
distance from urbanized land. The specific
feature of this temperature difference is how
quickly temperatures change.
The second hypothesis reflects
whether it is expected that urban areas will
longer than natural areas because natural
areas have a greater ability to process heat.
A final hypothesis suggests that the
UCF main campus is an urban heat island.
Failure to reject the first two hypotheses is
not sufficient to determine that the UCF
main campus is an urban heat island, but it is
necessary evidence to build such a case.
Material and Methods
Temperatures were collected on the UCF
main campus, which is located within the
Little Econlockhatchee River Basin and is
part of the St. John’s River watershed. The
main campus consists of approximately 520
acres of conservation land and 279 acres of
mixed use lands.11
Our project focused on data that
was collected from both natural and urban
lands with the emphasis on the progression
of urban heat island effects from the urban
area into natural lands. Limits on vertical
spread were held constant which also aided
in avoiding the effects of mixed wind on
temperature.
A total of four transects were
chosen with a total distance of 400 meters
per transect. All four of the transect lines ran
across Gemini Boulevard and radiated from
the campus center into natural lands. Our
Transects were 50% in the natural lands and
50% in the urban parts of the campus.
Each of the four transects were
assigned six Hobo Pro V2 data loggers, for a
total of 24 V2 loggers. Two controls were
assigned as well, one for the urban lands at
the center of UCF’s main campus, the
Student Union, and one placed out into the
natural lands, in the Pond Pines. All of the
transect lines were extended 200 meters into
11
University of Central Florida (2014). Natural Areas Land
Management Plan.
Landscape and Natural Resources.
http://www.green.ucf.edu/wpcontent/uploads/2014/04/2014-Land-Management-Plan.pdf
natural lands, as well as, 200 meters into
urban portions of the campus starting from
the middle of Gemini Boulevard. For
consistency, each individual logger was
spaced out at a distance of 80 meters apart
and secured to a height of 1.8 meters. All 26
loggers recorded temperatures at intervals of
every four hours for four consecutive weeks.
The six data loggers per transect
were aligned to provide temperature
readings along a linear gradient. Our study’s
two controls were determined on the
preconceived notion that highly urbanized
areas would have higher average
temperatures than the surrounding natural
lands. Therefore providing our study with
minimums and maximums with which could
be compared to the other 24 data loggers.
All data logger locations were
recorded using a Trimble device and
uploaded as point data into ArcGIS
software. The table data was joined to a
shape-file and converted to a map for easier
visualization (Figure 4). Microsoft Excel
was used to perform statistical analysis,
specifically a regression analysis compared
transect points over periods of time.
ANOVA tests were also performed to
compare temperature duration of urban
versus natural lands, as well as to compare
our controls in determining if urban areas
retain heat longer than their natural
counterparts.
Hobo Program software was used
to analyze and group data. Excel graphs and
tables were used for easy interpretation and
ArcGIS was used to interpolate a
temperature gradient across UCF.
Results
The temperature averages were taken based
on point location along the transect (Table
1). A regression test was used to estimate
the temperature relationship at each set time,
based on logger distance (Table 2).
The regressions showed variability
(greater than 50%) between each point per
all of the time frames; higher variability
(greater than 70%) was shown in all of the
points, except at time 1200 and 1600.
Statistical significance (Significance F in
Table 2) between the points indicates values
less than our p-value of 0.05 in all time
intervals.
To indicate if urban areas retain heat longer
than natural areas, the mean temperature for
the first three points were combined to
generate an average urban temperature, per
time. Likewise, the last three points were
combined to create an average natural lands
temperature, per time. The ANOVA test on
the two temperatures computed a p-value of
3.15 x 105 (Table 3).
Finally, the ANOVA test on the
temperatures at various times for urban and
natural controls resulted in a p-value of
.00455 (Table 4).
Table 2. Average daily temperatures were taken for all points along transects.
Table 1 To determine if temperatures decrease with distance from urban areas, a regression analysis was performed
Table 3. An ANOVA test for average urban and natural temperatures was used to conclude if urban areas remain hotter for a
longer duration than natural areas.
Table 4. To determine if UCF is an Urban Heat Island, an ANOVA test was performed on the urban and natural controls
The first hypothesis of this study
investigated potential differences in average
daily temperatures as distance from
urbanized land increased. Average daily
temperatures recorded at data loggers along
the entire transect showed high variability
(greater than 75%) at all times of day,
except the hottest during the hours of 1200
and 1600 (Table 2). Even so, variability was
still above 50% for these times (66% and
69%, respectively) and both were well
below our significance threshold of 0.05.
This validates our methods of spacing data
loggers 80 meters apart on a horizontal axis.
This appears to be far enough apart to detect
significant differences in air temperatures at
a height of 1.8 meters. This is important
because most studies focus on temperature
increases at the urban center which very
little research concerning the horizontal
spread of UHI impacts.12
12
Akbari, H. (2005). Energy Saving Potentials and Air
Quality Benefits of Urban Heat IslandMitigation. Lawrence
Berkeley National Laboratory.
Temperature
Discussion
90
85
80
75
70
65
60
55
50
45
40
0000
0400
0800
1200
1600
2000
Time of Day
Urban
Natural
Figure 3. Daily average temperatures of control points every four hours, averaged across all 4 week of the study (Figure 3) shows that the urban
control point recorded higher average daily
temperatures than the natural control at
every time of day.
The
greatest
difference
in
temperatures occurred during the hottest
hours of the day (hours 1200 and 1600),
which is contrary to the rest of the points
along the four transects, which saw their
lowest differences during these hours. This
difference could be a result of the surface
characteristics of where each data logger
was mounted. The urban control was
attached to a pole on the south side of a
large building, but loggers along the urban
portion of transects were not all placed
similarly. Some were attached to light poles
in the middle of parking lots where shade
was limited and air flow was higher, while
others were attached to trees or right next to
buildings, which could provide shade and
reduce airflow. The data loggers on the
natural side of the transects were more
consistently placed on trees and shrubs,
which did provide some shade. Therefore,
the effects of airflow and shading may be
less discernible among transects at peak
temperature hours as they are between
control points.
Making the transect as straight as
possible was given priority over attaching
loggers to similar objects, because in public
areas and parking lots, it was not feasible to
drive our own posts or attach the loggers to
any impermanent fixtures.
There was a potential source of error
in that one of the data loggers on the urban
side of one transect failed to transfer data
during a preliminary assessment of progress
during collection. We accidentally replaced
the wrong data logger, which meant that we
had no data for that point. However, when
we compared our analyses with and without
estimation, we determined that it made no
significant difference and, therefore, used
the estimation.
While there was high variability in
average daily temperature between all six
points of a transect, the three points on
urbanized land, as a group, showed
significantly
higher
average
daily
temperatures than those on natural lands, as
seen in (Table 3). This supports our first
hypothesis that average daily temperatures
will decrease with distance from urbanized
land, as well as our second hypothesis that
urban areas will retain heat longer than
natural areas because of the ability of natural
areas to process heat.
The mechanism of our second
hypothesis is supported by our findings that
the smallest differences in average daily
temperature were recorded during the hottest
hours in the day. Thus, the greatest
differences in temperature are occurring in
the cooling part of the day.
Our data generated a typical island
gradient characteristic of a UHI (Figure 4).
Most data loggers located immediately on
either side of the road dividing urban and
natural areas are in different thermal zones.
Figure 4. Heat map of UCF generated by average daily
temperatures at each point.
This suggests that the influence of
urban heat islands can extend a substantial
(over 100 meters) distance into natural
areas. However, this influence begins
decreasing almost immediately at the end of
the asphalt or pavement.
We failed to reject our hypothesis
that UCF is an Urban Heat Island because of
the high urbanization (concrete, pavement,
and other synthetic materials), significant
differences in daily average temperatures
between urban and natural areas, and
significant differences in ability to process
heat between urban and natural areas. These
are all recognized as indicators of a UHI.12
Acknowledgements
We would like to thank our
Professors, Alaina Bernard and Jennifer
Elliot, for their knowledge and help
throughout this whole process. Thank you to
Amanda Lindsay and the arboretum staff for
all of the time they put into helping us.