Production and Life
Textbook HW read p214-221
Answer the following questions
1. Why is Detritus important ?
2. Explain Nutrient Regeneration?
3. How is primary production measured?
4. What types of bacteria perform nitrogen
fixation?
5. What is a tertiary consumer?
Homework
• The Oceans Primary Productivity
• Study questions 1-14
• Page 4-13
Productivity Definitions
Primary Productivity
• The rate of carbon fixation under a square
meter of sea surface in a unit of time
• Which means how much glucose is made
in a set area during a set time.
What is Carbon Fixing Mean???
Carbon is “fixed” (built into an organic
molecule) through the process of
photosynthesis
Carbon is added to hydrogen and oxygen to
produce C6H12O6 aka_ glucose
Photosynthesis
• Fixes carbon into glucose using the
energy of sunlight
• 6CO2 + 6H2O + sunlight  C6H12O6 + 6O2
Chemosynthesis
• Fixes carbon into glucose using energy
from chemical compounds found at
hydrothermal vents (especially hydrogen
sulfide)
• Base of food chain that doesn’t require
sunlight
Respiration
• The breakdown of glucose in the presence
of oxygen to release Energy for life
processes
• C6H12O6 + 6O2  6CO2 + 6H2O + energy
• Gross primary productivity – total primary
production (carbon fixed)
• Net primary productivity – amount of
primary production minus the amount used
by respiration = amount available to
support other trophic levels
Trophic level ------ a feeding level
Biomass and Standing Crop
• Biomass = the organic matter that is
produced…Many times expressed as a
weight
• Standing crop = the total amount of plant
biomass present in a given volume of water
at a given instant
• This helps us determine how much life can
the area support –Remember Carrying
Capacity?
Figure 14.1
Figure 14.4
Water column stability = less nutrients therefore less BIOMASS
Note: Plenty of solar energy little nutrients – tropical location
How to measure primary
productivity
Plankton Net
• A fine mesh net used to collect samples of
microscope Plankton
Make a Plankton Net – 20 points
Plankton Net in Tow
Plankton net
is towed in
water.
Volume of
water is
calculated
Plankton is
collected in
tube and is
counted.
How do they count it?
Amount of plankton
found in one ml or cc
is compared with
volume of water
Measure standing crop
• 3 ways
– Filtration of cells – plankton tow
– Chlorophyll extraction
– Chlorophyll fluorescence – satellite imagery
• Drawbacks
– Patchy distribution
Satellite Imagery
One way to measure productivity
Measures chlorophyll concentration per
square meter of sea surface
Only measures top meter of water
Limited because blue light penetrates 100 m.
That means ONLY1% of possible water column
production is measured
Production is highest off of the land
masses …WHY?
What time of year is this in NY?
Compensation depth
• Depth where the rate of respiration = the
rate of photosynthesis
• Net productivity will be ZERO
Figure 14.8
Compensation depth decreases
with phytoplankton growth
More Production!
Result = reservoir of nutrients
below compensation depth
The area in the water column
where production equals
consumption
1. Biomass
2. Standing Crop
3. Compensation
depth
4. Photosynthesis
55.6%
27.8%
16.7%
yn
t
he
s
de
pt
Ph
ot
os
n
tio
ns
a
om
pe
C
is
h
ro
p
C
di
ng
St
an
B
io
m
as
s
0.0%
The total amount of plant biomass
present in a given volume of water
at a given instant
63.2%
21.1%
15.8%
n
rC
at
e
W
y
ili
t
ol
um
n
tio
ns
a
om
pe
St
ab
De
p
th
ro
p
C
di
ng
C
St
an
io
m
as
s
0.0%
B
1. Biomass
2. Standing Crop
3. Compensation
Depth
4. Water Column
Stability
More Productivity in the Nertic
Zones is a result of
Nutrient Runoff
More Light
Less Bacteria
Less Light
47.4%
31.6%
15.8%
t
Le
ss
Li
gh
te
ria
ac
B
ss
Le
or
e
M
ut
rie
nt
R
un
o
Li
gh
ff
t
5.3%
N
1.
2.
3.
4.
At Compensation Depth Net
Productivity will be
90%
10%
1%
0
47.4%
31.6%
15.8%
0
1%
%
10
%
5.3%
90
1.
2.
3.
4.
What percentage of water column
productivity is measured in Satellite
Imaging
100%
99%
1%
0%
15.8%
0%
1%
%
0.0%
99
0%
5.3%
10
1.
2.
3.
4.
78.9%
Carbon fixing results in the
production of
Carbon Dioxide
Methane
Glucose
Nitrates
44.4%
38.9%
16.7%
ar
bo
itr
at
es
N
e
G
lu
c
os
ne
et
ha
M
n
Di
o
xi
d
e
0.0%
C
1.
2.
3.
4.
Fastest Responders (in seconds)
3.89
5.09
Francesca Gonzales
Jane Newman
6.8
9.93
10.25
Shqiprie Dreshaj
Jessica Colantuono
Christian Caja
Factors that affect primary
productivity
•Light
•Nutrient availability
•Water column stability
Nutrients are brought by
• Runoff (from land)
OR
• WITHIN THE WATER COLUMN THROUGH:
• Upwelling (bottom water wells up as surface
water moves away)
• Overturn (denser sinks, less dense rises)
• Mixing (wind stirs up water column)
How to access deep nutrient
reservoir
• Overturn
– But strong winds may mix plankton too deep
for photosynthesis
• Upwelling
– Ekman spiral
– Divergence zones
Nutrient cycling
returns nutrients to the food chain
Nutrients
Nitrogen
Amino acids
Proteins
Phosphate
NRG molecules Phosphate
Cell membrane
Nucleic acids
Tests – e.g.
Silica dioxide
diatoms
Silica
Iron
Affects nutrient
uptake
Nitrate, nitrite,
ammonia
Generalized cycle
Available Nutrients
Decomposition
Producers
Consumers
Nitrogen cycle (Again)
Bacteria heavily involved
Ammonia  nitrite  nitrate for use by
producers
N2 fixed for use by producers
Phosphate Cycling
Nitrogen Cycling
Limiting Nutrient
The nutrient that runs out first and will limit growth
Usually Nitrogen “N”
N and P occur in similar concentrations, but
producers need more N
In Our fish tanks no fish = no nitrates = no algae
Redfield Ratio
The elemental composition of marine organic
matter (dead and living) is fairly constant. The
ratios of carbon to nitrogen to phosphorus
remaines the same from coastal (Neritic) to
open ocean (Oceanic) regions.
C :N :P = 106 : 16: 1
Carbon: Nitrogen : Phosphorus
(This is molar ratio.)
Nutrient Profile versus distance
from shore
more
less
shore
open ocean
Nutrient Profile versus water depth
Surface
M
nutrients
Eutrophication
Excess nutrients (N and P) from fertilizers,
sewage, etc., cause bloom in producers.
As nutrients are depleted, bloom dies all at
once.
Massive decomposition depletes oxygen 
fish kills
Alive, healthy and
Diverse
Dead- Algae
covered
Productivity in the World
What controls productivity by
latitude?
• Polar – light limits – 6 months of light or
darkness
• Mid latitudes – light and nutrients limit as
they vary over the year
• Tropics/ subtropics – nutrients limit
Figure 14.3
Peak points of both Nutrients and Solar energy = Peak Production
Figure 14.2
Figure 14.10
High latitudes
(near poles)
• Very productive in summer
• Long day length in summer
• Weak, constant sun plus fresh water layer
at surface  plankton held above
compensation depth
Figure 14.2
Middle latitudes
• Spring sun plus overturn from
winter/spring storms/winds plus slightly
stratified water column  spring bloom
• Mid summer heat stratifies water column
 nutrient depletion
• Autumn sun weakens, stratification
weakens, late summer storms replenish
euphotic zone with nutrients
Figure 14.2
Mid Latitude Nutrient Light availability by
season
Stratification of water column in
summer
Low Latitudes
(tropics / subtropics)
• Not very productive, except locally
(productivity
reef based>phytoplankton based
• Consistent sun year round
• Upwelling and overturn not very common,
and very localized
Figure 14.2
As you move from the Neritic to
Oceanic Zones
1. Nutrients Increase
2. Nutrients
decrease
3. Nutrients remain
the same
...
th
e
n
re
m
ai
N
ut
rie
nt
s
nt
s
ut
rie
N
N
ut
rie
nt
s
de
In
c
cr
ea
re
a
se
se
0.0% 0.0% 0.0%
The three elements in the Redfield
ratio are
1. Carbon Hydrogen
Oxygen
2. Carbon Hydrogen
and Phosphorus
3. Carbon Nitrogen
and Hydrogen
4. Carbon Nitrogen
and Phosphorus
...
an
...
en
an
Ni
tro
g
en
C
ar
bo
n
Ni
tro
g
n
ar
bo
C
n
ar
bo
C
C
ar
bo
n
Hy
d
Hy
d
ro
g
ro
g
en
en
O
...
an
...
0.0% 0.0% 0.0% 0.0%
The nutrient which runs out first
and will limit growth
Growth Nutrient
Running Nutrient
Standard Nutrient
Limiting Nutrient
t
ut
rie
n
t
N
ut
rie
n
g
m
iti
n
Li
St
an
da
rd
N
Nu
tr
ie
ni
ng
un
R
ro
w
th
Nu
tr
ie
nt
nt
0.0% 0.0% 0.0% 0.0%
G
1.
2.
3.
4.
The limiting Nutrient for most
primary producers is
Nitrogen
Phosphorus
Iron
Carbon
Ph
n
ar
bo
Iro
n
C
os
ph
o
itr
og
ru
s
en
0.0% 0.0% 0.0% 0.0%
N
1.
2.
3.
4.
Which is NOT a factor that would
affect primary productivity
1. Light
2. Nutrients
3. Water Column
Stability
4. Fish population
n
y
ul
at
io
po
p
sh
Fi
rC
ol
um
n
St
ab
ili
t
nt
s
ut
rie
N
at
e
W
Li
gh
t
0% 0% 0% 0%
Which factor most limits Polar
productivity
0%
0%
0%
0%
1.
2.
3.
4.
Nutrients
Light
Water Column Stability
Temperature
Which factor limits productivity in
the tropic regions?
Light
Water Stability
Nutrients
Temperature
0%
0%
0%
Te
m
pe
ra
tu
re
nt
s
ut
rie
ta
b
rS
at
e
W
N
ili
t
gh
t
y
0%
Li
1.
2.
3.
4.
Fastest Responders (in seconds)
0
0
Participant 1
Participant 2
0
0
0
Participant 3
Participant 4
Participant 5
Marine Food Chain
• A review of the food chain, food web and
food pyramid
• Review of flow of energy and related
terms
Food chain terms
• Autotroph
– Photoautotroph- makes food using light
– Chemotroph – makes food using chemical
compounds
• Heterotroph – gets energy from other organisms
• Producer – makes its own food (Autotroph)
• Consumer – consumes producers or other
consumers
• Herbivore- consumes plant matter
• Carnivore – consumes meats
• Food chains and food webs show trophic
(feeding) relationships between members
of a community
• Arrows show flow of energy
Food or Prey
Consumer
Food Chain
Food Web
More connections means
more stability
Very important reason to maintain
biodiversity
More food choices if one runs out the
organism has others and a better
chance to survive
Food Web
Figure 14 p.385
Food Pyramid
Pyramid of Numbers
Pyramid of Biomass
• The amount of
energy
transferred at
each step in a
food chain
averages
about 10% less lost in
very
productive
environments
where little
energy
expended to
get food
Figure 14.13