FERTILISER AND ITS EFFECT ON
LAKE WATER
10332
Fertiliser and its effect on lake water
Student number: 10332
Abstract
This project aims to determine the effect of time, different concentrations and types (organic
and inorganic) of liquid fertiliser on lake water and its oxygen levels, pH, turbidity and
transparency. This issue is crucial as water runoff from farms by rain washes fertiliser into
nearby water sources such as lakes. This spurs algal growth as it increases the nutrients.
These algae die and feed bacteria, taking oxygen out of the water and killing the fish. The
murkiness also prevents light reaching underwater plants for photosynthesis. Algal blooms
also can be toxic to both people and the environment. In the experiment, organic and
inorganic liquid fertiliser was mixed with different quantities of rain water to make different
concentrations. This water was mixed with lake water and over time was measured for
oxygen, pH, turbidity and transparency through different meters. The results revealed that
fertiliser increases oxygen levels, decreases the pH levels and decreases the transparency
of the lake water. Time further increases oxygen levels, increases the pH levels and reduces
the transparency of lake water. Higher concentrations of fertiliser less significantly increases
oxygen levels, increases the pH levels and more significantly reduces the transparency of
lake water. While, inorganic fertiliser increases the oxygen levels more, it -increases the pH
levels less and reduces the transparency of lake water less than organic fertiliser. The
fertiliser overall increased algal growth, increasing the oxygen level and pH level through
photosynthesis and absorbing carbon dioxide. This algal growth also clouded the water,
preventing light from transmitting. Therefore, this experiment was able to provide results to
better understand the effect different concentrations of organic and inorganic fertilisers have
on lake water. This effect is proven to be detrimental to the environment as the lake water is
altered. This will affect the types and populations of species and may permanently change
the lake in the long term.
Introduction
I came across this article (gawker.com 2015) about the
accidental spillage of milk from a factory and it was an
interesting read, detailing how it kills fish and threatens
the water supply by leaking into storm drains and
spurring algal growth. This highly polluting substance
has been described by Ben Woodhouse of the
Environment Agency: "The problem is that microbes in
the water work on decomposing the milk, which takes
the oxygen out of the water causing the fish to die. But
so far we have not found any dead fish. We think that,
because it is quite cold at the moment, the microbes
are fairly dormant." The runoff from farms containing
fertiliser has a similar more detrimental effect as it
promotes more growth, and is a very frequent issue.
1
Figure 1: In 1994 a Massachusetts tanker crashes,
spilling a large amount of milk
Source: http://gawker.com/5879234/spilt-milkactually-kills-fish-and-screws-up-the-water
Fertiliser and its effect on lake water
Student number: 10332
Industrial agriculture
Industrial agriculture is the leading cause of water pollution in the US, the 2000 National
Water Quality Inventory conducted by the Environmental Protection Agency (EPA)
discovered the source of pollution for 48% of stream and river water and 41% of lake water.
“ European agriculture is responsible for 60% of the total riverine flux of nitrogen to the North
Sea, and 25% of the total phosphorus loading. Agriculture also makes a substantial
contribution to the total atmospheric nitrogen loading to the North and the Baltic Seas. This
amounts to 65% and 55% respectively. Czechoslovakia reported that agriculture contributes
48% of the pollution of surface water” (Ongley, 1996)
A study by Ryding (1986) in Sweden showed lakes unaffected by industrial sources undergo
long-term change in nutrient status due to agriculture activities. During the period from 1973
to 1981, Lake Oren increased in nutrient status, transparency declined and suffered heavy
algal blooms. Agriculture is the leading source of pollution in that nation’s rivers and lakes,
nutrients ranking second.
However, not all waters have natural levels low in nutrients.
Lakes located in areas of rich agricultural soils are highly
enriched by nutrients from the natural erosion. In the prairie lakes
of Canada , lakes are green with algae while other parts of the
world such as Asia, ancient civilizations impacted water quality so
there are no longer natural levels of nutrients.
Figure 2: Aerial view of a manure spill
at a factory farm
Waterways are losing their ability to filter excess nitrates from
fertilizers and sewage, clearly indicated by a test of releasing a
concentrated nitrate solution containing a unique isotype of
Source:
https://www.flickr.com/photos/srapro nitrogen into 72 different streams.(scientificamerican.com 2015)
These were tracked and the amount it travelled downstream
ject/3239123135/in/setindicated the stream’s ability to naturally remove a pollutant, an
72157613129158691
indicator of its health. Typically denitrification, bacteria removing
excess fertilizer, converts nitrate to nitrogen which is then released into the atmosphere as
gas. However according to the study, bacteria only eliminated an average of 16% of the
nitrogen pollution while in most undisturbed streams they remove 43%. A boom in crops
such as corn for biofuel have made matters worse, increasing the nitrogen pollution in
Mississippi River Basin as much as 34% by 2022. (Donner and Kucharik (2008))
Effects
Industrial agriculture damages the environment, kills wildlife, sicken and kills people, and
wastes a large amount of water. Storage systems for the animal waste often leak during
large storms and overflow antibiotic residues and harmful bacteria into local water systems.
The excess of fertilizer sprayed on the crop of the farm also runs off into these water
systems. The most common water pollution in the US is an excess of nitrogen and
phosphorous, largely caused by fertilizer runoff.
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Fertiliser and its effect on lake water
Figure 3: Some species of algae
grow in clumps, sticking
together forming thick mats on
the surface of the water
Source:
http://floridaswater.com/algae/
Student number: 10332
There is a rapid growth of algae due to the increase of nutrients.
Algae are photosynthetic microorganisms that vary from small singlecelled forms to complex multi cellular forms. Increasing the density of
the water, these algal bloom block out the sunlight, reducing the
ability of plants to perform photosynthesis. Algae then become
stressed and die when they deplete the nutrient supply or move into
other waters. Dead algae then feed bacteria which consume all the
oxygen, killing the fish and plants. Some species of algae cause fish
kills directly by the production of toxins or clogging gills. This water
pollution is hard to regulate due to its non-definable sources ranging
from private lawns, agricultural fields to golf courses. Dead zones are
coastal areas where algal blooms have depleted the oxygen levels.
Few algae species produce toxins that kill fish, birds, mammals and
cause health problems for humans while others just have a bad smell
and ruin the taste of fish.
Water transparency
Water transparency is the measure of the depth of light
penetration into water, how easily light can pass through the
water. (http://rmbel.info 2015) It depends on the amount of
particles in the water which can be organic (sediment from
erosion) or organic (algae or phytoplankton). As the light
propagates (spreads) into the water, the light attenuates
(reduces in thickness) due to absorption and dispersion of
particles. The depth of which the light reaches depends on the
absorption or scattering of light caused by different particles in
the water, for example algae would absorb the light for
photosynthesis or dissolved matter would scatter the light.
In lakes, plants and algae are only able to grow in areas where
the sun penetrates. This top section of the lake is called the
euphotic zone while the edge of the lake that is shallow enough
for plants to receive light is called the littoral zone. The area of
the lake too deep for plants to grow is the limnetic zone.
Figure 4: Different paths of light in water
Source:
http://www.citclops.eu/transparency/wha
t-is-water-transparency
This transparency can be measure using a secchi disk. A plain white circular disk which is
mounted on a pole or line and lowered slowly into the water. The depth which the disk is no
longer visible is the measure of the transparency of the water. There are also light meters if
a sample of the water can be placed in a transparent container. This provides a
measurement of the amount of light.
Figure 5: Different lake zones in
reference to available sunlight
Source: http://rmbel.info/watertransparency/
3
Fertiliser and its effect on lake water
Student number: 10332
Algae and algal blooms
Scientists routinely collect water and algae samples and tests are
conducted to determine if algal toxins are present. These are
provided to agencies such as the Department of Health who take
out plans to respond to these blooms.
Algae are a natural component of the aquatic food chain and are
not often harmful to people, however overabundance are
aesthetically unappealing and harmful to the environment.
(floridaswater.com 2015)Some algae have an economic
importance because they are a source of carotene, glycerol, and
alginates and can be converted into a food source for aquatic
creatures. Some produce toxins leading to fish kills, numerous
reports of skin rashes, unappealing odors, and an accumulations of
foam and shoreline scums. The more common problems are the
environmental damage, impact on recreational activities and
commerce due to the green scum and unpleasant odor.
Algal blooms require sunlight, slow moving water and nutrients
(phosphorous and nitrogen) which is provided and worsened
due to the run-off from farms containing fertiliser.
Figure 6: An algal bloom takes over a
lake
Source:
https://upload.wikimedia.org/wikipedi
a/commons/7/74/River_algae_Sichua
n.jpg
pH levels
pH is the measurement of the hydrogen ion
concentration of a substance. The pH scale ranges
from 1-14, 7 is neutral, 1-6 is acidic and 8-14 is
basic. This pH balance is important in water ways in
maintaining aquatic ecological conditions. It
determines the solubility and the amount of chemical
constituents such as nutrients and metals to be
utilized by aquatic life.
Photosynthesis (which occurs more in daylight
hours and growing season) uses dissolved carbon
dioxide which acts like carbonic acid in water,
therefore reducing the acidity of water and
increasing the pH while respiration and
decomposition lower pH levels. Lake water contain
‘shock absorbers’ which prevent major changes in
pH. Ability to resist change in pH (and keeping the
pH between the natural 6.5 to 8.5 range) through
various chemical reactions is called a lakes
buffering capacity.
Pollution results in higher algal and plant growth,
increasing pH levels. Small changes may not have
a direct impact on aquatic life but greatly influence
the availability and solubility of chemicals.
4
Figure 7: The increase of nitrate or phosphate from
fertilisers into water causes eutrophication
Source:
http://www.bbc.co.uk/schools/gcsebitesize/science/
edexcel/problems_in_environment/pollutionrev4.sht
ml
Fertiliser and its effect on lake water
Student number: 10332
Change in pH in the water in aquatic systems have various effects:
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Approaching 5, non-desirable plankton and mosses may invade and populations of
fish disappear
Below 5- fish disappear ,the bottom is covered with undecayed material and mosses
dominate other areas
Below 4.5- Water is devoid of fish and aluminium attached to mineral in nearby soil
may be released into lakes, killing many fish and stimulating excess mucus
formation. Calcium levels are lowered to a point where fish cannot produce eggs.
Highly alkaline above 9- Causes death in fish, damage to to their gills, eyes and skin
and the fish are unable to dispose of metabolic wastes. This may also increase the
toxicity of other substances.
Different fertilisers affect the pH differently, some raising the pH and other lowering it.
Substances in the fertilisers that raise the pH of soil include lime and potassium carbonate
while substances in fertilisers that lower the pH of soil include ammonium nitrate, ammonium
sulfate and sulfur coated urea.
Algae also affects the physical and chemical conditions in the water body. Algae remove
carbon dioxide during photosynthesis and raises the pH by increasing the level of hydroxide.
During respiration however, carbon dioxide is produced lowering hydroxide and pH. During
photosynthesis, algal blooms also produce large amounts of oxygen but decreases it in
respiration.
Eutrophication
Eutrophication is the enrichment of surface waters with plant nutrients often due to run-off
from the land. This leads to algal blooms and dense growth of plant life, which can take over
the water body.
Symptoms and impacts ( fao.org 2015):
○
○
○
○
○
○
○
○
○
○
Increase in production and biomass of phytoplankton, attached algae,
macrophytes
A shift in habitat characteristics resulting in a change in variety of aquatic
plants
Fish replaced by less desirable species of fish
Certain algaes release toxins
Effect in public water supplies, including taste, odour problems, especially
during periods of algal bloom
Deoxygenation water resulting in fish kills
Clogging of irrigation canals with aquatic weeds
Loss recreational water due to slime, weed infestation and noxious odour
from decaying algae
Affected navigation due to dense weed growth
Economic loss due to change in fish species, kill,etc
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Fertiliser and its effect on lake water
Student number: 10332
Figure 8: Fertilisers can cause
eutrophication in lake water
Source:
http://www.bbc.co.uk/schools/gcsebites
ize/science/ocr_gateway/chemical_reso
urces/fertilisers_cropsrev3.shtml
Trophic status
Trophic status describes the relationship between nutrient status of lake and
growth organic matter in the lake. It is the total weight of biomass in a given
water body. The amount of nitrogen, phosphorous and other biologically
useful nutrients are the main indicators of a body of water’s trophic state
index.
Figure 9: An diagram of a
Oligotrophic lake
Source:http://rmbel.info/
lake-trophic-states-2/
Trophic classifications (rmbel.info 2015):
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●
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Oligotrophic - Lake with low productivity due to low nutrient content.
Low algal production, clear waters, high drinking water quality, an ample
amount of oxygen at the bottom and many fish species are many
characteristics of this type. Oligotrophic lakes are common in cold
locations underlain by resistant igneous rocks. Low algal concentration
allows deeper light penetration and less decomposition so when
organisms die, they sink to the bottom and are decomposed by
microbes and invertebrates.
Mesotrophic - Lakes with intermediate productivity, commonly clear
water lakes and ponds with aquatic plants and medium level of
nutrients. These lakes separate into layers during Summer with the top
layer being warm from the sun and containing algae, making it rich in
oxygen while the bottom layer remains cooler and anoxic in midSummer (low in oxygen). Organisms dying and decomposing at the
bottom of the lake uses up the oxygen and causes this change.
Eutrophic - Lakes with high biological productivity. Excessive nutrients
allow these water bodies to support an abundance of aquatic plants,
making the pond dominated by aquatic plants or algae. When plants
dominate, the water is clear but when algae dominate, the water is
darker. Algae take part in photosynthesis, supplying oxygen to fish, but
when an excessive algal bloom occurs, fish are killed due to respiration
by algae and bacteria. Since the lake has so much biomass there is an
abundance of decomposition at the bottom, using up the oxygen making
the bottom of the lake anoxic in Summer.
6
Figure 10: A diagram of a
Mesotrophic lake
Source:http://rmbel.info/
lake-trophic-states-2/
Fertiliser and its effect on lake water
●
Student number: 10332
Hypertrophic - Nutrient-rich lakes with frequent severe algal blooms
and low transparency. These lakes depths are visible less than 3 feet,
have more than 40 micrograms/litre total chlorophyll and more than
100 micrograms/liter phosphorous. Low oxygen levels create dead
zones at lower depths.
Figure 12 : Table of the relationship
between trophic levels and lake
characteristics
Figure 11 : An diagram of a
Eutrophic lake
Source:http://rmbel.info/lak
e-trophic-states-2/
Source:http://www.fao.org/docrep/w25
98e/w2598e06.htm
Figure 13: Relationship between transparency (secchi
depth) and lake trophic state
Source:http://rmbel.info/water-transparency/
Types of polluting minerals and substances contributed by industrial agriculture
 Nutrients - The nutrients nitrogen and phosphorus promote plant growth. Over
fertilization creates an excess of nutrients that when leaked into water, causes a
harmful plant growth called an algal bloom. The more acidic water kills the plants and
the excessive growth of the algal bloom (eutrophication) makes the water hypoxic
(low in oxygen). (sustainabletable.org 2015)
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➢ Nitrogen - This organic matter must first be mineralized by soil microbes into
ammonium or nitrate for plants to utilize and so are easily leached from soil.
➢ Phosphorous - This binds quickly to soil and only in heavy rainfall, causing
erosion, would it wash away.
➢ Potassium - Plant roots rapidly absorb this nutrient and so, it is a little threat.
Ammonia and nitrates - These when dissolved in water are highly toxic to fish. The
ammonia converts into dangerous nitrates and when ingested, are poisonous to
humans. This causes fatal oxygen levels for babies, spontaneous abortions, cancer
and other implications.
Pathogens and other microorganisms - Disease-causing microorganisms transfer
into water supplies during run off during either irrigation or rainfall. These develop as
a result of farms and eutrophication causing high nutrient levels.
Antibiotics and hormones - These are injected into livestock or added to the feed,
which is then excreted, and compromises the reproductive processes of fish.
Organic matter and other solids - Animal bedding, wasted feed, soil, dust, hair and
feathers increase the level of bacteria in the water, reducing oxygen levels water and
killing fish.
7
Fertiliser and its effect on lake water
Student number: 10332
Problems restoration
Eutrophic and hypertrophic lakes tend to be shallow. In areas of rich soils, lake bottom
sediments contain nutrient-enriched soil particles eroded from surrounding soils. These
particles are enriched with phosphorus and form a large nutrient pool that provides for rooted
plants. This greatly offsets measurements taken by river basin managers to control
eutrophication by controlling external agriculture phosphorous sources. Due to modern
technology, there are alternative and more cost-effective methods of controlling loss of
phosphorus by oxygenation and chemically treating sediments. However this is still
expensive. Introducing molluscs and other species of fish to get rid of algal blooms may be
extremely effective but introducing new species come with a lot of risk as they will upset the
food system and may be invasive. Aerators can supply oxygen and nutrient inputs can be
controlled. An alteration in pH may also limit the growth of algae, but again, this will upset
the living conditions for other species of flora and fauna. Shoreline vegetation can be planted
to reduce erosion, absorb nutrients and lower the pond’s water table.
Climate change and human population growth will further degrade the water quality
prompting an immediate need for water managers to understand how to minimize algal
blooms. Methods of diverting excess nutrients, altering nutrient ratios, physical mixing,
shading water bodies with opaque liners or water-based stains, application of algaecides
and herbicides proved ineffective, costly and/or impractical especially for large, complex
ecosystems. Reducing nitrogen and/or phosphorus inputs are difficult and expensive to
control, especially in agricultural areas. Internal loading of nutrients from sediments prevents
improvements in water quality and the use of algaecides can reduce algal blooms
temporally, but are expensive and pose risks to humans, livestock and wildlife. It also does
not control the main cause of the problem which is an abundant amount of nutrients. Another
method is biomanipulation, altering the food web to restore the ecosystems health, which
has an effect on the water quality that is short-lived.
Fertiliser
Fertilisers are natural or manmade substances that assist in improving the growth of plants
and the fertility of soils. They are applied to the soil or plant foliage. Plants need sunlight, air,
water, nutrients and an appropriate temperature to survive. They photosynthesise to produce
oxygen and glucose, which is broken down to provide energy to grow. Plants also need
nutrients from the soil (chemical elements), which fertilisers help provide. Soils may not have
enough nutrients due to nutrient depletion caused by the removal of plant and animal
products, leaching or gaseous loss. Fertilisers vary but all have a specific amount of the 3
major nutrients:
●
●
●
Nitrogen - helps the overall plant growth and the development of healthy leaves
Phosphorous- aids in root and flower development, increases the rate of growth of
the plant and is used by plants to store and transfer energy
Potassium - regulates plant metabolism and affects water pressure inside and
outside the plant cells
Fertilisers also contain some secondary nutrients such as calcium, sulphur and magnesium
as well as some trace elements including boron, chlorine, manganese, iron, copper, zinc and
molybdenum.
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Fertiliser and its effect on lake water
Student number: 10332
Types of fertilisers include:
●
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●
●
●
Organic - Organic matter (carbon-based matter) is living or once
living material including manures, crop residues, compost and
byproducts. These fertilisers have less nutrients than inorganic
but will not burn plants or poison pets and does not require a
specific timetable of application and watering due to its slowrelease of nutrients. It has long-term positive effects without
damaging groundwater. Organic fertiliser is more costly than
Figure 14: An example of organic
inorganic fertiliser but is less likely to be washed away.
fertiliser
Types of organic fertilisers include:
Source: http://www.saosis.com/wp○ Plant based - e.g. alfalfa meal and compost. Quicker
content/uploads/2014/11/Types-ofthan others, but aids more in soil conditioning rather
Organic-Fertilizers.jpg
than nutrient enrichment. It helps drainage and
moisture retention.
○ Animal based - e.g. manure, bone meal, blood meal.
This fertiliser adds lots of nitrogen and helps in leafy
and strong plant growth.
○ Mineral based - This adds nutrients to the soil and raises or lowers pH levels
which is needed for healthy plant growth
Inorganic - This fertiliser is formed from non-living sources
and is what most commercial fertilisers are. They are
primarily derived from chemical compounds, mineral or
synthetic and come in powder, pellet, granule or liquid. This
type of fertiliser can however be used immediately, unlike
organic, and are easily absorbed by plants. However
besides essential nutrients, it contains compounds and salts
the plant cannot absorb and are left in the soil, often creating
a build-up and changing the chemistry of the soil. It also
does not contain organic matter to enhance soil structure,
aeration , moisture retention or support beneficial soil
Figure 15: An example of inorganic
organisms.
fertiliser
○ Mineral - Inorganic chemicals collected by
Source:
extraction or manufactured chemical processes
http://www.todayshomeowner.com/i
(eg the artificial synthesis of ammonia which then
mages/article/organic-vs-chemicalis used to manufacture urea and ammonium
fertilizer-4.jpg
nitrate and the reaction of sulphuric acid on rock
phosphate to make superphosphate). It is a
combination of naturally occurring mineral ores
containing many essential multi-nutrients.
Acid soluble - Chemically treated to make the nutrients soluble in water. (e.g.
adding sulphuric acid to rock phosphate convert to water soluble superphosphate)
Liquid - Fast acting and require application every 2 or 3 weeks
Solid - Dry and must be watered in but is much easier control the quantity and the
specific application location. There is quick release and slow release solid fertiliser.
9
Fertiliser and its effect on lake water
Student number: 10332
Ways to prevent run-off of fertilisers in farms
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Using less acidifying nitrogen fertilisers
Sowing early to maximise the crops ability to recover the soil nitrate
Deep rooted plants can absorb the nitrate more rapidly
Avoiding excessive irrigation.
Minimise the removal of product from the soil.
Use cropping rotations to minimise the excessive accumulations of soil organic
matter under pasture.
Apply nitrogen in small amounts frequently rather than all at once, to minimise nitrate
leaching
Redirecting waste water discharges, stormwater collection and retention
improvements
Repairing septic tanks
How normal citizens can reduce water pollution
● Use the correct amount of fertilizer
● Apply sparingly
● Follow manufacturer’s directions on the bag
● Choose fertilizers with low or no phosphates
● Choose slow-release fertilizers as they stay in the soil over a longer
period of time
● Only fertilize during growing season
● Use pesticides, herbicides and fungicides only when necessary
● Consider organic or nontoxic products
● Maintain your storm water system
● Don’t blow yard waste and grass clippings into streets or storm
drains
● Repair automobile leaks
● Don’t dump oils, chemicals or paint in your yard or down storm
drains
● Dispose of antifreeze, motor oil and batteries at designated
collection centers
● Pick up and properly dispose of pet waste
10
Figure 16 : An example of an
organic slow-release fertiliser
Source:
https://www.woolworths.com.
au/Content/wowProductImag
es/medium/727630.JPG
Fertiliser and its effect on lake water
Student number: 10332
Construction sites sediments - Sediments from the soil can wash into waterways and
create problems for aquatic life. Turbidity, cloudy water caused by suspended matter, can
reduce the amount of sunlight able to reach plants. Siltation, settling of matter suspended in
water on the bottom of the water body, destroys bottom-dwelling plants. Here are some
ways to reduce this:
●
●
●
●
Develop good management practices to minimize erosion
Have storm water treatment facilities
Cover mounds of dirt with a tarp to prevent wind and rain carrying the sediment into
waterways
Surround large piles of dirt with hay bales or cloth fences to minimise erosion
Figure 17: Construction by the water
in China
Source:http://www.puddingandchops
ticks.com/wpcontent/gallery/everydaychina/construction_water.jpg
Conclusion
Run-off of fertilizers and nutrients are a leading cause of water pollution and is a rapidly
growing problem. The algal blooms created by these water pollutants negatively affects the
oxygen level, pH, density and transparency of the water body. The demand for freshwater
resources is expected to increase dramatically, making protecting these diminishing water
resources a major environmental issue that will be complicated as climate change, species
invasions and pollution continue to degrade the water quality and quantity. The control and
management of eutrophication is complex and will require the collective efforts of scientists,
politicians and citizens to develop effective, long lasting techniques to eventually restore
these treasured aquatic communities.
11
Fertiliser and its effect on lake water
Student number: 10332
Aim
To investigate the effect of time, different concentrations and types (organic and inorganic)
of liquid fertiliser on lake water and its oxygen levels, pH and transparency
Hypothesis
1. Fertiliser will not affect oxygen levels, will lower the pH levels and reduce the
transparency of the lake water
2. Time will fdecrease oxygen levels, lower the pH levels and reduce the transparency
of lake water
3. Higher concentrations of fertiliser will more significantly decrease oxygen levels,
lower the pH levels and reduce the transparency of lake water
4. Inorganic fertiliser will decrease the oxygen levels, lower the pH levels and reduce
the transparency of lake water more than organic fertiliser
Equipment list


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







Clear 700ml containers x 27
2.4 litres of rainwater
16.2 litres of lake water
500 ml of liquid organic fertiliser (Yates Thrive All Purpose liquid plant food)
500 ml of liquid inorganic fertiliser (Charlie Carp Premium Organic Fertiliser)
Stirring rod
Turbidity meter
Light meter
pH meter
Oxygen meter
Turbidity tube
Measuring cup
Measuring syringe
Light meter
Figure 1 and 2:
pH meter
Equipment
used in the Oxygen meter
experiment.
Organic fertiliser
Plastic
containers
containing lake
water with
fertiliser and
rain water
added
Empty plastic
container
Inorganic fertiliser
Measuring cup
12
Plastic syringe
Fertiliser and its effect on lake water
Student number: 10332
Method
1. 300.6 ml of rainwater , measured with a measuring cup , was mixed with 18 ml of
liquid organic fertiliser , measured with a measuring syringe ,in a container to make
the 16.7:1 rainwater to fertiliser ratio concentration.
2. Step 1 was repeated for 300 ml of rainwater with 2 ml (150:1 concentration), 6 ml of
liquid organic fertiliser (50:1 concentration)and 450 ml rainwater with 1 ml of liquid
organic fertiliser (450:1 concentration)
3. Steps 1-2 were repeated for liquid inorganic fertiliser
4. A 700 ml plastic container was filled with 600ml of lake water, measured with a
measuring cup
5. 100 ml of 16.7:1 concentration organic fertiliser was added, measured with a
measuring cup
6. The water was stirred with a stirring rod
7. With a black marker, the number container was written on the side of the container
and the type and concentration of this number container recorded
8. The container was lifted and the amount of light transmitted through the water
detected with a light meter and results recorded
9. The amount of oxygen was measured with an oxygen meter and results recorded
10. The pH was measured with a pH meter and results recorded
11. A turbidity tube was lowered into the water and the height of the water where the disk
could not be seen was recorded
12. Steps 4-11 were repeated 2 times
13. Steps 4-12 were repeated for 150:1, 50:1 and 450:1 concentrations of organic
fertiliser
14. Steps 4-13 were repeated for inorganic fertiliser
15. Another 700ml plastic container was filled with 600ml of lake water, measured with a
measuring cup
16. With a black marker, the number was written on the side of the container and the
type and concentration of this number container recorded
17. Steps 15-16 were repeated 2 times
18. The containers were left in an unshaded open area
19. Steps 8-11 were repeated every day for 10 days and results were recorded
Figure 3:
Measuring the pH and oxygen of the
lake water containing rain water and
fertilizer using a pH meter and oxygen
meter
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Fertiliser and its effect on lake water
Student number: 10332
Results
Average light absorbed/reflected by lake water containing
different concentrations of inorganic and organic fertiliser
(lux)(2dp)
Organic Organic Organic Organic
Inorganic Inorganic Inorganic Inorganic
Days 16.7
50
150
450
Control 16.7
50
150
450
1
466.67
368.33
320.33
309.67
281.50
301.33
312.00
275.67
297.33
2
669.67
385.67
161.50
-17.00 -177.50
61.33
-163.00
-166.00
-228.50
3
300.67
217.50
164.50
188.50
179.00
152.00
170.00
161.00
174.00
4
129.00
96.00
88.50
85.00 -110.00
73.50
76.50
7.00
81.00
5
579.33
544.33
499.00
447.33
207.00
196.67
228.67
234.00
273.33
6 1505.00 1394.00 1297.00 1182.50
581.50
689.00
726.00
708.50
807.00
7 1345.67 1309.00 1115.00
874.00
396.67
440.00
463.33
496.67
480.00
8 1222.50 1176.00
840.00
974.00
452.00
550.00
609.00
534.00
699.00
9
868.00
844.00
854.00
720.00
381.00
433.00
503.00
475.00
545.00
10 1815.00 1762.67 1600.67 1186.67
512.00
665.00
719.00
840.00
1133.67
11
313.33
359.33
311.67
288.00
139.67
191.00
211.33
204.67
261.33
12 1433.50 1386.00 1193.50
881.00
692.00
672.00
764.00
818.50
1017.50
13
372.00
366.33
346.00
279.33
135.00
213.00
203.67
198.00
270.33
Average light absorbed/reflected by lake water
containing different concentrations of organic
fertiliser
Average light absorption (lux)
2000.00
1500.00
1000.00
500.00
0.00
1
2
3
4
5
6
-500.00
7
8
9
10
Days
Fertiliser concentration:
16.7
50
150
14
450
Control
11
12
13
Fertiliser and its effect on lake water
Student number: 10332
Average light absorption (lux)
Average light absorbed/reflected by lake water
containing different concentrations of inorganic
fertiliser
Days
Fertiliser concentration:
Average light absorption (lux)
Average light absorbed/reflected by lake
water containing different concentrations of
organic and inorganic fertiliser
2000.00
1500.00
1000.00
500.00
0.00
1
2
3
4
5
6
-500.00
7
8
9
10
Days
Fertiliser concentration:
Organic 16.7
Organic 50
Organic 150
Organic 450
control
Inorganic 16.72
Inorganic 50
Inorganic 150
Inorganic 450
15
11
12
13
Fertiliser and its effect on lake water
Student number: 10332
Average oxygen levels of lake water containing different
concentrations of organic and inorganic fertiliser(% oxygen)
(2dp)
Organic Organic Organic Organic
Inorganic Inorganic Inorganic Inorganic
Days 16.7
50
150
450
Control 16.7
50
150
450
1
35.25
36.10
36.90
36.70
35.70
36.50
36.30
36.20
35.90
2
23.05
20.70
18.75
18.30
45.25
33.25
34.85
35.10
35.40
3
30.35
26.00
22.95
32.85
42.40
41.45
43.05
47.10
49.45
4
32.55
25.80
19.05
47.60
39.95
39.40
40.35
43.65
45.95
5
43.60
48.80
51.70
58.10
57.80
16.20
54.50
60.10
67.90
6
43.45
48.80
55.05
67.70
32.86
44.50
58.75
75.40
76.40
7
39.00
48.93
55.40
66.87
58.20
37.77
57.90
67.17
67.47
8
44.10
51.10
52.50
61.70
53.20
25.90
51.10
60.60
65.00
9
37.70
55.50
65.20
64.30
50.80
44.37
47.50
56.90
70.60
10
25.87
44.30
50.07
44.67
42.95
39.10
41.13
42.03
52.33
11
31.77
67.40
69.77
58.30
50.75
45.83
52.37
52.80
75.87
Average oxygen levels of lake water containing
different concentrations of organic fertiliser
Average oxygen levels (% oxygen)
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
1
2
3
4
5
6
7
8
Days
Fertiliser concentration:
16.7
50
150
16
450
Control
9
10
11
Fertiliser and its effect on lake water
Student number: 10332
Average oxygen levels of lake water containing
different concentrations of inorganic fertiliser
Average oxygen levels (% oxygen)
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
1
2
3
4
5
6
7
8
9
10
11
Days
16.7
50
150
450
Control
Average oxygen levels (% oxygen)
Average oxygen levels of lake water containing
different concentrations of organic and
inorganic fertiliser
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
1
2
3
4
5
6
7
8
9
10
Days
Fertiliser concentration:
Organic 16.7
Organic 50
Organic 150
Organic 450
Inorganic 16.72
Inorganic 50
Inorganic 150
Inorganic 450
17
control
11
Fertiliser and its effect on lake water
Student number: 10332
Average pH levels of lake water containing different
concentrations of organic and inorganic fertiliser (pH)(2dp)
Days
1
2
3
4
5
6
7
8
9
10
11
12
Organic Organic Organic Organic
Inorganic Inorganic Inorganic Inorganic
16.7
50
150
450
control 16.7
50
150
450
6.65
7.33
7.69
8.06
8.98
8.46
8.53
8.56
8.65
6.63
7.47
7.81
7.78
9.03
8.38
8.49
8.67
8.74
7.42
7.88
7.95
8.36
9.16
8.56
8.71
8.98
9.29
7.59
7.83
8.06
9.10
8.90
8.35
8.57
8.87
9.21
8.42
8.79
9.01
9.46
9.19
8.10
9.29
10.40
10.38
8.43
8.78
9.06
9.64
9.28
8.32
10.15
10.73
10.56
8.67
8.99
9.37
9.95
9.31
8.41
10.18
10.61
10.49
8.62
9.07
9.39
10.04
9.30
7.97
10.17
10.79
10.62
7.67
10.21
10.50
10.18
9.24
8.45
8.92
9.29
9.91
7.60
10.83
10.44
9.94
9.71
8.86
9.46
9.51
10.02
7.26
10.42
10.38
9.65
9.34
8.78
9.18
9.15
9.66
7.04
10.78
10.47
9.63
9.44
8.71
9.24
9.13
9.96
Average pH levels (pH)
Average pH levels of lake water containing
different concentrations of organic fertiliser
Fertiliser concentration:
18
Fertiliser and its effect on lake water
Student number: 10332
Average pH levels (pH)
Average pH levels of lake water containing different
concentrations of inorganic fertiliser
Days
Fertiliser concentration:
Average pH levels of lake water containing
different concentrations of inorganic and
organic fertiliser
Average pH levels (pH)
12.00
10.00
8.00
6.00
4.00
2.00
0.00
1
2
3
4
5
6
7
8
9
10
11
Days
Fertiliser concentration:
Organic 16.7
Organic 50
Organic 150
Organic 450
Inorganic 16.7
Inorganic 50
Inorganic 150
Inorganic 450
19
control
12
Fertiliser and its effect on lake water
Student number: 10332
Average turbidity of lake water containing different
concentrations of organic and inorganic fertiliser
(turbidity)(2dp)
Organic Organic Organic Organic
Inorganic Inorganic Inorganic Inorganic
Days 16.7
50
150
450
control 16.7
50
150
450
1
72.3
117.5
55.3
20.5
10.5
3.3
2.6
3.8
8.7
2
17.3
25.3
27.2
15.6
1.3
6.2
2.5
8.1
2.7
3
367.6
128.1
38.6
8.5
1.5
11.9
5.9
3.2
0.6
4
391.7
93.5
24.8
8.5
5.3
13.6
7.5
10.2
6.1
5
7.0
6.5
15.0
15.8
4.4
38.5
61.6
117.9
72.6
6
40.1
75.5
150.8
101.3
4.9
9.5
3.0
8.8
21.1
7
230.7
194.2
91.7
80.5
10.6
19.5
16.2
6.2
9.4
8
194.9
224.2
139.9
92.8
6.3
18.3
18.7
11.7
12.7
9
190.7
216.3
95.6
91.2
4.3
7.4
50.5
4.9
10.5
10
391.7
340.1
178.1
124.3
10.3
6.2
8.7
10.9
29.3
11
421.5
367.2
249.5
140.4
31.7
173.6
23.9
14.9
25.1
Average turbidity (turbidity)
Average turbidity of lake water containing
different concentrations of organic
fertiliser
Fertiliser concentration:
20
Fertiliser and its effect on lake water
Student number: 10332
Average turbidity of lake water containing
different concentrations of inorganic fertiliser
200.0
Average turbidity (turbidity)
180.0
160.0
140.0
120.0
100.0
80.0
60.0
40.0
20.0
0.0
1
2
3
4
5
6
7
8
9
10
11
Days
Fertiliser concentration:
control
16.7
50
150
450
Average turbidity of lake water containing
different concentrations of inorganic
fertiliser
450.0
Average turbidity (turbidity)
400.0
350.0
300.0
250.0
200.0
150.0
100.0
50.0
0.0
1
2
3
4
5
6
7
8
9
10
Days
Fertiliser concentration:
Organic 16.7
Organic 50
Organic 150
Organic 450
Inorganic 16.7
Inorganic 50
Inorganic 150
Inorganic 450
21
control
11
Fertiliser and its effect on lake water
Student number: 10332
Pictures of results
Figure 4: Day 1 (Containers from left to
right containing concentrations organic
16.7, 50, 150, 450, inorganic 16.7, 50,
150, 450, control)
Figure 5: Day 6 (Containers
from left to right containing
concentrations organic 16.7, 50,
150, 450, inorganic 16.7, 50,
150, 450, control)
Figure 6: Day 8 (Containers from
left to right containing
concentrations organic 16.7, 50,
150, 450, inorganic 16.7, 50,
150, 450, control)
Green coloured water from
algae growth
Algae
Bubbles
Clear water due to lack
of fertiliser
22
Figure 7: Day 15 (Containers from left to
right containing concentrations organic
16.7, 50, 150, 450, inorganic 16.7, 50,
150, 450, control)
Fertiliser and its effect on lake water
Student number: 10332
Discussion
Overall, the results supported parts of the hypothesis while disproving other parts. There
were a variety of patterns and trends in the results.
Light absorption and reflection
When the fertilisers were added, the light absorption and reflection instantly increased. This
is due to the increase in particles from the fertiliser. The light absorption and reflection for
control was the lowest as there was less particles in the liquid due to the lack of fertiliser. For
organic, the more concentrated it was there was a higher light absorption as this increases
the number of particles. However for inorganic, as concentration increased the light
absorption decreased. This may be due to the fact that the inorganic fertiliser dissolves into
the water and is no longer suspended in the water, as well as the fact that there is not a lot
of growth of algae. Over time, the different concentrations varied in increasing and
decreasing, but overall they all increased except for organic 150. This is due to the growth of
algae as the nutrients have increased which spurs its growth. Some may have decreased
due to the death of algae or a lack of growth as nutrients decrease. There are peaks at days
6, 8, 10 and 12 with the highest being day 10. There are dips at days 4, 7, 9, 11 and 13 with
the lowest being day 13. Control decreased the most over time while only organic 150
increased in light absorption and reflection. Organic fertilisers had a higher light absorption
overall than organic fertilisers, with organic 16.7 being the highest followed by organic 50
and organic 150. Organic fertilisers may produce more algae growth as its nutrients may be
more suitable for algae.
Oxygen levels
The oxygen levels instantly increased for both organic and inorganic. This may be due to the
fact that when mixing, more oxygen may have been dissolved. Over time both organic and
inorganic oxygen levels increased. Aquatic photosynthesis is light dependent and produces
oxygen, and so during the day the dissolved oxygen produced peaks. As more algae grows,
more photosynthesis reactions take place and so the product of oxygen increases. There are
peaks at day 3, 5, 6, 9 and 11 and dips at day 2, 4 and day 10. This may be due to the
decrease of sunlight for that particular day for photosynthesis to use as energy. Control had
oxygen levels at approximately the middle of all the measurements. As concentration
decreased, oxygen levels increased. The higher concentrations blocked a lot of the sunlight,
and so algae may not have received enough light to photosynthesise, and so dies,
decreasing the oxygen levels. Control had quite a different pattern with a sudden dip at day
6. Inorganic had higher oxygen levels to start with but over time it became more scattered
throughout. The highest average oxygen levels were inorganic 450 followed by organic 450.
The lowest were the containers containing the highest concentrated fertilisers. Overall, they
mostly increased in oxygen levels over time except for organic 16.7.
pH levels
The pH levels instantly decreased for both organic and inorganic. Over time, pH levels
increased a slight amount for both organic and inorganic. As concentration decreased, pH
levels increased. Control had readings around the middle and inorganic overall had higher
pH readings. Overall, pH increased over time. The inorganic fertilisers had higher pH levels
than the organic fertilisers at the beginning but over time, most of the organic fertilisers had
higher pH. Using pH paper, organic gave a yellow colour which is a pH reading around 4 and
the inorganic gave a blue colour which is a pH reading around 7. The organic fertiliser had a
lower pH and so at first it had a lower pH. As more algae grows, the removal of carbon
23
Fertiliser and its effect on lake water
Student number: 10332
dioxide raises the pH levels. There was an overall dip in pH at day 4 and 9 and an overall
increase at day 3. This may be the effect of the amount of light on the rate of photosynthesis,
which affects the removal of carbon dioxide and in turn, affecting the pH of the water. Most
of the inorganics except for 16.7 increased from day 4 to 8. Control was around the middle
and the most constant.
Turbidity levels
The turbidity levels overall increased over time. The fertiliser clouds the water, then providing
nutrients for algae to grow, which also increases the turbidity. There is not a clear pattern
followed by all concentrations except for a peak at day 5 and increase from day 6 to 11.
Organic 16.7 has an abnormal significant increase of turbidity on days 3 and 4. Organic had
a higher turbidity reading than the inorganic readings. For organic, as concentration
increased turbidity increased. While for inorganic as concentration decreased, turbidity
increased. For organic, the increase of the concentration of fertiliser increases the turbidity
and also provides more nutrients for more algae to grow. Too concentrated inorganic
fertiliser may not have been optimal for algal growth, therefore higher concentrations may
not have caused as much algal growth. The control stayed constant at measurements close
to zero. Control had no fertiliser and so the turbidity barely changed. The highest turbidity
readings were organic 16.7 and organic 50.
Appearance
The colouring of the water changed significantly over time as shown in the pictures. Organic
16.7 was the most murky and brown once the fertiliser was added, followed by organic 50,
150 and 450. The containers containing inorganic fertiliser as well as the control remained
relatively clear. By day 6, organic 16.7 became a deeper brown while the other containers
containing organic fertiliser became green from the growth of algae. The containers
containing inorganic fertiliser as well as the control still remained very clear. By day 15, all
the colours grew significantly darker and the containers containing inorganic fertiliser had
some marine plants grown on it. The surface of most of the containers grew some algae and
water plants. Overall, these observations showed that over time the algae grew more dense
inside the water but organic had more visible algae than inorganic, perhaps due to the fact
that algae had more abundant growth in the containers containing organic fertiliser.
Water samples were also taken and looked at under a microscope (pictures shown in the
appendix) revealing microscopic living organisms and plants.
Hypothesis
The results matched part of the hypothesis while disproving others. Fertiliser did decrease
the pH levels and transparency, as predicted, as the fertilisers were more acidic and clouded
the water. Time reduced the transparency of lake water and higher concentrations more
significantly reduced the transparency of lake water as higher concentrations were cloudier
and contained more particles for light to be absorbed or reflected off. Time reduced the
transparency of the lake water as algal growth occurs. However, fertiliser and time increased
the oxygen levels. This may be due to the mixing of the water which dissolved more oxygen
as well as photosynthesis that takes place in the algae grown, increasing the oxygen levels
during the day which was the time the measurements were taken. The pH levels increased
over time, due to photosynthesis as algae takes in carbon dioxide. Higher concentrations
less significantly increased oxygen levels and pH levels as too high concentrations may
have not created the optimal conditions for maximum algal growth. Also, the higher
concentration did not allow as much sunlight to provide as energy for photosynthesis for the
24
Fertiliser and its effect on lake water
Student number: 10332
algae, reducing oxygen levels and reducing the amount of carbon dioxide taken in which
reduces pH levels. Inorganic fertiliser increases the oxygen levels more, increases pH levels
less and reduces the transparency of lake water less than organic fertiliser. Inorganic
fertiliser may have not created as much algal growth as organic, therefore increasing the
oxygen levels more, increasing pH levels less and reducing the transparency less.
Reliability, validity and accuracy
The results were reliable as the measurements for each of the identical containers were
similar. By averaging the results, it provided a more reliable result. The method was
performed accurately with exact measurements measured using a measuring cup. The
experiment was also repeated 3 times for accuracy by the larger sample size. The results
were accurate as it is supported by the research in secondary sources.
The method is valid as it tests the effect of the fertiliser on the transparency of water through
the use of the light meters before and after the fertiliser was added. This measures the
change in transparency that may occur. Different types of concentrations of fertilisers are
used to determine the effect of these on the transparency of water. The containers were then
left in an open area and checked for their transparency almost every day for 13 days,
providing clear results of the effect of time on the transparency of the water. Turbidity, pH,
light and oxygen meters were then used almost every day to measure the turbidity, pH, light
and oxygen content in each of the containers. Variables such as size of container, type of
container, amount of water and fertiliser and the environment were controlled, making the
results more reliable and the method more valid. Equipment were carefully washed with
distilled water between measurements to ensure no contamination between containers.
Errors ,improvements and further investigations
During the experiment, a few errors occurred. Near the end, some measurements were not
able to be taken due to other commitments preventing me from measuring the containers. I
was also unable to measure more than one container for turbidity due to lack of time and so
the experiment would have been improved if all containers were measured.
This experiment was unable to replicate the movement of lake water as well as the
vegetation and wildlife that lives in and on it. This could have been improved by using a
water pump or something similar to constantly move the water. To improve the accuracy, a
larger sample size could have been used. If the experiment was able to be done longer,
more results would have been able to be achieved and the pattern of the effect time has on
the water would have been more substantially done. This is due to the fact there may have
been further changes such as when the algae dies and decomposes and when bacteria
takes over to consume this algae. Near the end, a lot of the water evaporated leaving barely
any water and so, the amount of water should be increased to prevent the likelihood of all
the water evaporating.
This investigation could be furthered by investigating the effect of stagnant and moving water
on pH, oxygen levels and light absorption/reflection. This would provide an understanding on
the difference between moving and stagnant lakes. The effect of temperature could have
been also investigated as global warming is affecting the temperature of the earth and may
affect the ecosystems in lakes.
Therefore, this experiment was able to provide results to better understand the effect
different concentrations of organic and inorganic fertilisers on lake water. The effect of this
fertiliser that transfers to the lake water through run-off is proven to be detrimental to the
environment as the lake water is altered. This will affect the types and populations of species
25
Fertiliser and its effect on lake water
Student number: 10332
and may permanently change the lake in the long term. Strategies must be put in place to
prevent this from happening.
Conclusion
1. Fertiliser increases oxygen levels, decreases the pH levels and decreases the
transparency of the lake water
2. Time further increases oxygen levels, increases the pH levels and reduces the
transparency of lake water
3. Higher concentrations of fertiliser less significantly increases oxygen levels, less
significantly increases the pH levels and more significantly reduces the transparency
of lake water
4. Inorganic fertiliser increases the oxygen levels more, increases the pH levels less
and reduces the transparency of lake water less than organic fertiliser
Acknowledgement
I would like to acknowledge any assistance I received in the duration of creating this report.
Firstly, a teacher who suggested the use of lake water and rain water to more accurately
match the real life example of rain water washing fertiliser into the lake.
Secondly, a teacher who provided me with equipment and suggestions to use the turbidity
tube as well as the oxygen meter and pH meter to further investigate the effects fertiliser had
on the lake water. She also aided a lot in the development of the report and what to place in
it.
Thirdly, a teacher who helped in the early development of the report.
26
Fertiliser and its effect on lake water
Student number: 10332
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27
Fertiliser and its effect on lake water
Student number: 10332
Moll, E. (n.d.). Fertilizers As Pollutants. [online] Home Guides | SF Gate. Available at:
http://homeguides.sfgate.com/fertilizers-pollutants-78452.html [Accessed 14 Dec. 2015].
Ongley, E. (1996). Chapter 3: Fertilizers as water pollutants. [online] Fao.org. Available at:
http://www.fao.org/docrep/w2598e/w2598e06.htm [Accessed 14 Dec. 2015].
Portal.ncdenr.org, (n.d.). NCDEQ - Algal Blooms. [online] Available at:
http://portal.ncdenr.org/web/wq/ess/eco/blooms [Accessed 3 Feb. 2016].
Pudding and Chopsticks, (2012). Build it up and tear it down. [image] Available at: [Accessed
14 Dec. 2015].
RMBEL, (n.d.). Lake Trophic States - RMBEL. [online] Available at: http://rmbel.info/laketrophic-states-2/ [Accessed 14 Dec. 2015].
RMBEL, (n.d.). Water Transparency - RMBEL. [online] Available at: http://rmbel.info/watertransparency/ [Accessed 14 Dec. 2015].
saosis, (n.d.). Organic Fertilizer. [image] Available at: [Accessed 14 Dec. 2015].
Sciencelearn Hub, (2013). Fertiliser. [online] Available at:
http://sciencelearn.org.nz/Contexts/Soil-Farming-and-Science/Looking-Closer/Fertiliser
[Accessed 14 Dec. 2015].
Today's Homeowner, (n.d.). Organic fertilizer. [image] Available at:
http://www.todayshomeowner.com/images/article/organic-vs-chemical-fertilizer-4.jpg
[Accessed 14 Dec. 2015].
Vimpany, I. and Lines-Kelly, R. (2004). Fertilisers and the environment | NSW Department of
Primary Industries. [online] Dpi.nsw.gov.au. Available at:
http://www.dpi.nsw.gov.au/agriculture/resources/soils/improvement/environment [Accessed
14 Dec. 2015].
Wikipedia, (2003). Secchi disk. [online] Available at: https://en.wikipedia.org/wiki/Secchi_disk
[Accessed 14 Dec. 2015].
Wikipedia, (2008). Trophic state index. [online] Available at:
https://en.wikipedia.org/wiki/Trophic_state_index [Accessed 14 Dec. 2015].
Woolworths, (2016). B-green Organic Garden Fertiliser Slow Release. [image] Available at:
https://www.woolworths.com.au/Content/wowProductImages/medium/727630.JPG
[Accessed 14 Dec. 2015].
28
Fertiliser and its effect on lake water
Student number: 10332
Self evaluation
I believe I was able to carry out the experiment effectively. I was able to plan out what time
would be allocated for each part of the SRP. Background information was researched in
depth, really providing me with a deep understanding of what I am investigating. The trials
gave me an idea of what would happened and what could go wrong, and I changed the
experiment according to that. I was also able to effectively communicate with teachers to
sort out equipment and they provided me with ways to improve the experiment and to
change the experiment. This included using rain water and lake water to make the
experiment more related to the real life example, changes in equipment due to the
availability of them and changing the quantities of the water. When problems arose with the
equipment, I was able to communicate with the science teacher effectively and organise a
change. When the experiment started, I was able to measure everything and really identify a
pattern. Despite occasional abnormal readings, in the discussion I was able to identify a
pattern and give reasons why this may have occurred.
29
Fertiliser and its effect on lake water
Student number: 10332
Appendix
Day 1 (27 February 2016)
Day 6 (4 March 2016)
Day 7 (5 March 2016)
30
Fertiliser and its effect on lake water
Student number: 10332
Day 8 (6 March 2016)
Day 15 (13 March 2016)
31
Fertiliser and its effect on lake water
Student number: 10332
Microscope pictures
Control
Inorganic 16.7
32
Fertiliser and its effect on lake water
Student number: 10332
Inorganic 450
Organic 16.7
33
Fertiliser and its effect on lake water
Student number: 10332
Organic 50
Organic 150
Organic 450
34
Fertiliser and its effect on lake water
Student number: 10332
Raw results
Day 1 LIGHT
Organic
16.7
50
1
170
260
2
170
270
3
150
255
AVERAGES
Control
150
307
322
300
630
163.33 261.66 309.66
466.66 368.33 320.33
1
2
3
AVERAGES
pH
Organic
16.7
6.62
6.66
6.67
6.65
1
2
3
AVERAGES
Oxygen
Organic
16.7
35
35.5
35.25
35.25
NTU
lux
Turbity
Organic
16.7
72.3
4
50
7.36
7.39
7.23
7.32
150
7.66
7.9
7.5
7.68
323.33
309.66
Inorganic
16.7
357 1
375
345 2
389
358 3
360
633
351.5
374.66
281.5
301.33
450
8.07
8.08
8.03
8.06
Inorganic
Control
16.7
8.98 1
8.46
8.99 2
8.5
8.97 3
8.42
8.98
8.46
450
340
320
310
50
8.53
8.59
8.47
8.53
150
8.56
8.51
8.61
8.56
450
8.65
8.79
8.51
8.65
50
35.9
33.4
39.6
36.3
150
36.2
36.8
35.6
36.2
450
36.8
35.9
35
35.9
50
2.6
4
150
3.8
3
450
8.7
3
Control
50
36.1
36.8
37.5
36.8
150
37.1
36.9
36.7
36.9
450
41.8
36.7
31.6
36.7
Inorganic
16.7
35.7 1
38.4
38.3 2
33.5
33.1 3
37.6
35.7
36.5
50
150
450
399
360
343
342
347
335
351
365
329
676
633
364 357.33333 335.6667
312 275.66667 297.3333
Control
50
117.5
4
150
55.3
4
450
20.5
4
10.5
3
35
Inorganic
16.7
3.3
4
Fertiliser and its effect on lake water
Day 2 LIGHT
Organic
16.7
50
150
450 Control
1
2
190
300
615
498
865
804
3
201
430
900
230.33 514.33
669.66 385.66
834.5
1187 878 (77)
839 1500
(1068)
(-432)
1013
996
955
1013
-17
-177.5
pH
Organic
16.7
1
6.71
2
6.63
3
6.55
6.63
Oxygen
Organic
16.7
1
32.9
2
13.2
3
23.05
23.05
NTU
lux
Student number: 10332
Turbity
Organic
16.7
17.3
111
834.5
161.5
Inorganic
16.7
50
150
450
1
2
899
833
1480
868
1247
1107
1293
1254
3
1063
993
931.66
61.33
1174
1011
1174
-163
1177
1011
1177
-166
1273.5
1045
1273.5
-228.5
935
50
7.47
7.38
7.56
7.47
150
7.80
7.82
7.81
7.81
450 Control
7.92
8.99
7.63
9.07
7.78
9.03
7.78
9.03
Control
50
27.7
13.7
20.7
20.7
150
23.7
13.8
18.75
18.75
450
21.2
15.4
18.3
18.3
47.2
43.3
45.25
45.25
Control
50
25.3
110
150
27.2
109
450
15.6
96
1.3
94
36
Inorganic
16.7
1
8.34
2
8.42
3
8.38
8.38
50
8.50
8.47
8.49
8.49
150
8.75
8.58
8.67
8.67
450
8.80
8.67
8.74
8.74
Inorganic
16.7
1
31.8
2
34.7
3
33.25
33.25
50
34.4
35.3
34.85
34.85
150
34.1
36.1
35.1
35.1
450
35.3
35.5
35.4
35.4
Inorganic
16.7
6.2
109
50
2.5
110
150
8.1
95
450
2.7
91
Fertiliser and its effect on lake water
Day 3 LIGHT
Organic
16.7
50
1
136
190
2
97
193
3
92 191.5
409
108.33 191.5
300.66 217.5
pH
Organic
16.7
1
7.42
2
7.49
3
7.39
7.43
Oxygen
Organic
16.7
1
31.1
2
29.6
3
30.35
30.35
50
7.89
7.88
7.86
7.88
150
242
247
244.5
244.5
164.5
150
7.94
7.95
7.95
7.95
Student number: 10332
450 Control
261
270
254
264
257.5
267
446
446
257.5
267
188.5
179
450 Control
8.39
9.09
8.43
9.16
8.26
9.23
8.36
9.16
Control
50
26.5
25.5
26
26
Turbity
Organic
16.7
50
367.6 128.1
358.3
32
40
39
150
23.5
22.95
22.4
22.95
450
31.8
33.9
32.85
32.85
42.6
42.4
42.2
42.4
Control
150
38.6
28
450
8.5
27
1.5
30
37
Inorganic
16.7
1
277
2
296
3
315
50
278
287
269
150
266
308
287
450
288
274
260
296
152
278
170
287
161
274
174
Inorganic
16.7
1
8.59
2
8.53
3
8.56
8.56
50
8.70
8.71
8.71
8.71
150
8.95
9.01
8.98
8.98
450
9.29
9.31
9.27
9.29
Inorganic
16.7
1
41.4
2
41.5
3
41.45
41.45
50
42.6
43.5
43.05
43.05
150
46.9
47.3
47.1
47.1
450
49.4
49.5
49.45
49.45
Inorganic
16.7
11.9
27
50
5.9
27
150
3.2
29
450
0.6
30
Fertiliser and its effect on lake water
Day 4 LIGHT
Organic
16.7
1
26
2
28
3
30
157
28
129
pH
Organic
16.7
1
7.61
2
7.59
3
7.555
7.585
Oxygen
Organic
16.7
1
32.55
2
32.5
3
32.6
32.55
Turbity
Organic
16.7
391.7
22
50
60
63
60
150
70.5
68
67
61
96
68.5
88.5
50
7.86
7.83
7.8
7.83
150
8.03
8.05
8.085
8.05
Student number: 10332
Inorganic
16.7
1
85
2
82
3
83.5
50
86
75
80.5
150
150
150
150
450
76
76
76
78.5
-110
83.5
73.5
80.5
76.5
150
7
76
81
450 Control
9.1
8.75
9.12
9.04
9.08
8.895
9.1
8.89
Inorganic
16.7
1
8.27
2
8.35
3
8.42
8.35
50
8.57
8.59
8.54
8.57
150
8.87
8.89
8.85
8.87
450
9.19
9.21
9.21
9.20
Inorganic
16.7
1
36.3
2
39.4
3
42.5
39.4
50
40.35
40.9
39.8
40.35
150
43.1
43.65
44.2
43.65
450
47.8
44.1
45.95
45.95
Inorganic
16.7
13.6
24
50
7.5
24
150
10.2
24
450
6.1
23
450 Control
74
80
70
79
72
76.5
72
85
Control
50
23.3
25.8
28.3
25.8
150
19.05
19.6
18.5
19.05
450
46.5
47.6
48.7
47.6
38.5
41.4
39.95
39.95
Control
50
93.5
24
150
24.8
24
450
8.5
23
5.3
23
38
Fertiliser and its effect on lake water
Day 6 LIGHT
Organic
16.7
50
1
20
64
2
31
68
3
26
50
605
25.7
60.7
579.3 544.3
pH
Organic
16.7
1
8.48
2
8.42
3
8.36
8.42
Oxygen
Organic
16.7
1
43.6
2
45.9
3
41.3
43.6
Turbity
Organic
16.7
7
16
50
8.85
8.73
8.79
8.79
150
108
110
100
106.0
499.0
150
9.01
9.37
8.65
9.01
Student number: 10332
Inorganic
16.7
1
339
2
325
3
336
50
307
290
307
150
285
299
304
450
269
234
267
323.0
207.0
333.3
196.7
301.3
228.7
296.0
234.0
256.7
273.3
450 Control
9.88
9.19
9.46
10.03
9.04
8.35
9.46
9.19
Inorganic
16.7
1
8.1
2
8.4
3
7.7
8.07
50
9.64
9.29
8.94
9.29
150
10.9
9.9
10.4
10.4
450
9.86
10.9
10.38
10.38
Inorganic
16.7
1
11.9
2
20.9
3
15.8
16.2
50
52.7
54.5
56.3
54.5
150
58.6
62.7
59
60.1
450
65.8
69.4
68.5
67.9
Inorganic
16.7
38.5
13
50
61.6
12
150
117.9
12
450
72.6
12
450 Control
158
329
167
310
148
330
157.7
447.3
Control
50
48.8
50.2
47.4
48.8
150
53.4
51.7
50
51.7
450
59.4
56.8
58.1
58.1
57.8
52.4
63.2
57.8
Control
50
6.5
14
150
15
14
450
15.8
14
4.4
14
39
Fertiliser and its effect on lake water
Day 7 LIGHT
Organic
16.7
50
1
81 173
2
139 269
3
110 221
150
330
306
318
110 221
1505 1394
318
1297
pH
Organic
16.7
1
8.425
2
8.41
3
8.44
8.425
Oxygen
Organic
16.7
1
44.4
2
43.45
3
42.5
43.45
Turbity
Organic
16.7
40.1
49
50
8.85
8.78
8.71
8.78
150
9.06
9.05
9.07
9.06
Student number: 10332
Inorganic
16.7
1
827
2
865
3
846
50
849
769
809
150
821
832
826.5
450
715
741
728
953.5
581.5
846
689
809
726
826.5
708.5
728
807
450 Control
9.635
9.28
9.65
9.21
9.62
9.35
9.635
9.28
Inorganic
16.7
1
8
2
8.38
3
8.25
8.315
50
10.15
10.11
10.19
10.15
Inorganic
16.7
1
39.2
2
44.5
3
49.8
44.5
50
58.75
59.3
58.2
58.75
150
74.7
75.4
76.1
75.4
450
74.6
78.2
76.4
76.4
Inorganic
16.7
9.5
54
50
3
51
150
8.8
52
450
21.1
52
450 Control
428
970
437
937
432.5
953.5
432.5
1182.5
Control
50
48.8
46.6
51
48.8
150
55.5
55.05
54.6
55.05
450
78.1
63.4
61.6
67.7
0.712
65
32.856
32.856
Control
50
75.5
49
150
150.8
50
450
101.3
57
4.9
53
40
150
450
10.76
10.55
10.73
10.53
10.7
10.58
10.73 10.55333
Fertiliser and its effect on lake water
Student number: 10332
Day 8 LIGHT
Organic
16.7
1
33
2
50
3
80
50
85
88
100
150
290
200
215
450 Control
448
780
420
780
440
790
54.33333
1345.667
91
1309
235
1115
436 783.3333
874 396.6667
Inorganic
16.7
1
880
2
830
3
840
50
820
820
780
150
740
730
760
450
750
700
770
850 806.6667 743.3333
440 463.3333 496.6667
740
480
pH
Organic
16.7
50
150
450 Control
1
8.64
9.11
9.35
9.92
9.28
2
8.61
8.93
9.34
9.99
9.32
3
8.75
8.94
9.43
9.95
9.34
8.666667 8.993333 9.373333 9.953333 9.313333
Inorganic
16.7
50
150
450
1
8.39
10.23
10.61
10.56
2
8.41
10.13
10.62
10.42
3
8.42
10.19
10.59
10.48
8.406667 10.18333 10.60667 10.48667
Oxygen
Organic
16.7
50
1
44.7
51.6
2
39.4
46.7
3
32.9
48.5
39 48.93333
Inorganic
16.7
1
37.8
2
36.4
3
39.1
37.76667
Turbity
Organic
16.7
230.7
14
Control
150
450
55.3
65.6
54.7
67.7
56.2
67.3
55.4 66.86667
61.5
57.3
55.8
58.2
Control
50
194.2
15
150
91.7
15
450
80.5
15
10.6
22
41
Inorganic
16.7
19.5
18
50
150
450
61.4
69
68.4
54.1
67.6
66.2
58.2
64.9
67.8
57.9 67.16667 67.46667
50
16.2
18
150
6.2
18
450
9.4
19
Fertiliser and its effect on lake water
Day 9 LIGHT
Organic
16.7
1
42.5
2
32
3
53
42.5
1222.5
pH
Organic
16.7
1
8.63
2
8.6
3
8.615
8.615
Oxygen
Organic
16.7
1
46.8
2
44.1
3
41.4
44.1
Turbity
Organic
16.7
194.9
Student number: 10332
Inorganic
16.7
1
723
2
593
3
658
50
612
576
648
150
619
687
755
450
532
512
522
769
452
658
550
612
609
687
534
522
699
450 Control
10.03
9.25
10.05
9.35
10.04
9.3
10.04
9.3
Inorganic
16.7
1
7.91
2
7.97
3
8.03
7.97
50
10.17
10.23
10.11
10.17
150
10.76
10.79
10.81
10.79
450
10.73
10.62
10.50
10.62
Inorganic
16.7
1
26.8
2
25.4
3
25.5
25.9
50
54.7
49.7
48.9
51.1
150
81.4
59.3
41.1
60.6
450
75.4
63.8
55.8
65
Inorganic
16.7
18.3
25
50
18.7
26
150
11.7
26
450
12.7
24
50
104
89
74
150
203
201
205
450 Control
234
765
256
812
212
730
89
1176
203
840
234
974
50
9.18
8.96
9.07
9.07
150
9.39
9.39
9.39
9.39
Control
50
61.2
41
51.1
51.1
150
52.5
49.8
55.2
52.5
450
49.8
61.7
73.6
61.7
54.8
59.6
45.2
53.2
Control
50
224.2
25
150
139.9
25
450
92.8
25
6.3
25
42
Fertiliser and its effect on lake water
Student number: 10332
Day 10 LIGHT
Organic
16.7
50
1
165
183
2
162
159
3
159
171
150
159
176
148
450 Control
287
654
296
649
302
671
162
868
161
854
295
720
pH
Organic
16.7
1
7.65
2
7.77
3
7.60
7.67
Oxygen
Organic
16.7
1
40.1
2
38.6
3
34.4
37.7
Turbity
Organic
16.7
190.7
19
171
844
50
10.22
10.21
10.20
10.21
150
10.50
10.55
10.44
10.50
Inorganic
16.7
1
585
2
567
3
594
50
508
530
498
150
548
537
535
450
470
468
472
658
381
582
433
512
503
540
475
470
545
450 Control
10.31
9.24
10.18
9.33
10.05
9.15
10.18
9.24
Inorganic
16.7
1
8.37
2
8.48
3
8.49
8.45
50
8.92
8.91
8.92
8.92
150
9.29
9.36
9.22
9.29
450
9.83
9.91
9.99
9.91
Inorganic
16.7
1
47.4
2
42.2
3
43.5
44.37
50
46.8
46.7
49
47.5
150
60.1
52.8
57.8
56.9
450
68.9
78.4
64.5
70.6
Inorganic
16.7
7.4
19
50
50.5
20
150
4.9
20
450
10.5
22
Control
50
48.7
53.9
63.9
55.5
150
64.9
65.9
64.8
65.2
450
61.8
56.9
74.2
64.3
53.4
49.8
49.2
50.8
Control
50
216.3
20
150
95.6
19
450
91.2
20
4.3
25
43
Fertiliser and its effect on lake water
Student number: 10332
Day 12
LIGHT
Organic
Inorganic
16.7
50
150
450 Control
16.7
50
150
450
1
44
24
84
91
271
1
195
182
198
149
2
53
14
70
125
236
2
214
217
199
137
3
37
30
66
84
268
3
203
164
177
118
358
382
385
388
398
395
399
396
396
44.67
22.67
73.33
100.00
258.33
204.00
187.67
191.33
134.67
313.33 359.33
311.67
288.00
139.67
191.00
211.33
204.67
261.33
16.7
50
150
450
pH
Organic
Inorganic
16.7
50
150
450 Control
1
7.7
10.85
10.15
10.02
9.71
1
8.91
9.52
9.55
10.07
2
7.63
10.83
10.48
9.88
9.65
2
8.85
9.44
9.52
9.96
3
7.47
10.80
10.68
9.93
9.78
3.00
8.81
9.43
9.46
10.02
7.60
10.83
10.44
9.94
9.71
8.86
9.46
9.51
10.02
Day 11 LIGHT
Organic
16.7
50
150
450 Control
1
60
107
164
780
1220
2
70
80
224
640
1150
3
65
165
450
660
1222
1880
1880
1880
1880
1880
65 117.3333 279.3333 693.3333
1368
1815 1762.667 1600.667 1186.667
512
44
Inorganic
16.7
1
1290
2
1280
3
1075
1880
1215
665
50
1186
1206
1001
1850
1131
719
150
450
1176
741
890
770
964
638
1850
1850
1010 716.3333
840 1133.667
Fertiliser and its effect on lake water
Day 13 LIGHT
Organic
16.7
50
1
65
107
2
59.5
80
3
54
134
1493 1493
59.5
107
1433.5 1386
pH
Organic
16.7
1
7.32
2
7.32
3
7.15
7.26
50
10.48
10.46
10.31
10.42
Oxygen
Organic
16.7
50
1
28.5 46.9
2
26.7 45.3
3
22.4 40.7
25.87 44.30
Turbity
Organic
16.7
50
391.7 340.1
35
34
Student number: 10332
450 Control
469
751
685
801
595
851
1464
1493
583
801
881
692
Inorganic
16.7
1
733
2
855
3
794
1466
794
672
50
659
699
739
1463
699
764
150
625.5
627
624
1444
625.5
818.5
450
451
460.5
470
1478
460.5
1017.5
150
10.09
10.34
10.7
10.38
450 Control
9.75
9.31
9.47
9.29
9.73
9.41
9.65
9.34
Inorganic
16.7
1
8.85
2
8.76
3
8.72
8.78
50
9.26
9.15
9.13
9.18
150
9.16
9.14
9.15
9.15
450
9.68
9.58
9.72
9.66
150
45.6
47.5
57.1
50.07
Control
450
41.6
47.6
43.7
42.7
42.2
43.7
44.67
42.95
Inorganic
16.7
1
41.2
2
40.4
3
35.7
39.10
50
40.6
41.6
41.2
41.13
150
42.6
42.3
41.2
42.03
450
51.5
51.3
54.2
52.33
Control
Inorganic
16.7
6.2
26
50
8.7
27
150
10.9
27
450
29.3
25
150
243
272.5
302
1466
272.5
1193.5
150
178.1
30
450
124.3
30
10.3
32
45
Fertiliser and its effect on lake water
Day 14 LIGHT
Organi
c
16.7
50
1
41
43
2
21
43
3
34
27
404
404
32 37.6666
7
372 366.333
3
150
42
82
35
399
53
346
pH
Organi
c
16.7
50
150
1
7.13
10.83
10.02
2
7.11
10.79
10.5
3
6.88
10.71
10.9
7.04 10.7766 10.4733
7
3
Oxyge
n
Organi
c
16.7
1
31.3
2
32.3
3
31.7
31.76
Turbit
y
Organi
c
16.7
450
92
134
94
386
106.666
7
279.333
3
450
9.8
9.42
9.68
9.63333
3
Student number: 10332
Inorgan
ic
Control
16.7
219 1
140
216 2
184
207 3
165
349
376
214
163
135
213
Inorgan
ic
Control
16.7
9.46 1
8.84
9.25 2
8.77
9.62 3
8.51
9.44333
8.70666
3
7
150
182
186
154
372
174
198
50
150
9.31
9.14
9.21
9.08
9.19
9.18
9.23666 9.13333
7
3
450
108
90
86
365
94.6666
7
270.333
3
450
10.01
9.9
9.97
9.96
Control
50
73.9
64.9
63.4
67.4
150
64.6
72.8
71.9
69.76
450
61.9
55.1
57.9
58.3
Inorgan
ic
16.7
55.8 1
47.4
48.6 2
46.8
52.9 3
43.3
50.75
45.83
50
175
181
155
374
170.333
3
203.666
7
Control
50
150
249.5
44
450
140.4
45
31.7
43
46
Inorgan
ic
16.7
173.6
50
50
52.4
52.6
52.1
52.36
150
53.4
52.7
52.3
52.8
450
72.6
77.8
77.2
75.86
50
23.9
49
150
14.9
48
450
25.1
46