3.3 Review for AICE Marine Exam

3.3 Nutrient Cycles

3.2.10 Draw, describe, & interpret pyramids of energy, #s and biomass, including those that
incorporate parasites & periods of plankton bloom

Producer

Primary consumer

Tertiary consumer

Secondary consumer

Pyramid of energy, biomass, or #s

Pyramid of biomass

Pyramid of numbers with parasite

algae

small crustacea

sea
bream

nematodes

tuna

phytoplankton

zooplankton

Pyramid of plankton bloom (in English Channel)

Because the phytoplankton have a short turnover time;
they reproduce rapidly & are consumed quickly

Do NOT draw a
pyramid with
this triangular
shape!!

DRAW all of
these
“block”-shaped
pyramids!

https://youtu.be/ug8f3YPoE2s

In rare situations, for some ecosystems, you will see an inverted/upside-down pyramid of numbers. The reason is, if the
numbers present in an ecosystem are counted after most have been eaten, then the pyramid will be inverted and look as
though there are fewer plankton than consumers.

3.3 Nutrient Cycles

3.3.1 Understand that nutrient is a generic term for substances that are required by an organism for growth, repair, energy, or normal metabolism

3.3.2 Understand that nutrients can include gases such as CO2, ions such as Mg2+, CO3

2-, PO4

3- and organic compounds such as carbohydrates, lipids & proteins

3.3.3 State the chemical elements that make up carbohydrates, lipids, and proteins

3.3.4 State that large molecules are made from smaller molecules, limited to starch & cellulose from glucose, proteins from amino acids, & lipids from fatty acids
& glycerol

3.3.5 Understand that some nutrients supply organisms with a source of essential elements and these elements have important biological roles

3.3.6 Understand that some nutrients are soluble and that there is a reservoir of these nutrients dissolved in the ocean which is available to producers and
consumers

3.3.7 Explain the processes by which the reservoir of dissolved nutrients is replenished, including upwelling, runoff, tectonic activity, dissolving of atmospheric
gases, excretion & decomposition

3.3.8 Understand that the reservoir of dissolved nutrients is depleted by uptake into organisms

3.3.9 Understand that the nutrients taken up by organisms in food chains can be removed by harvesting

3.3.10 Explain why productivity may be limited by the availability of dissolved nutrients

3.3.11 Describe the carbon cycle, limited to combustion, photosynthesis, respiration, decomposition, formation of fossil fuels, formation and weathering of rocks
containing carbonate

3.3.1 Understand that nutrient is a generic term for substances that are required by an organism
for growth, repair, energy, or normal metabolism

Nitrogen/nitrate

Carbon/carbonate

Magnesium ion

Calcium ion

Phosphorus/phosphate

Assimilation in Nutrient Cycles

●All nutrients have a biotic and abiotic phase within a marine ecosystem. A nutrient
goes from abiotic to biotic when it is absorbed and assimilated by the producers
(autotrophs). For example, carbon dioxide (abiotic), is found in the atmosphere and
in ocean water, it is then fixed during photosynthesis into glucose by the producers
(plants). This can later be converted into other molecules needed by the producer,
like starch.

●During the biotic phase, nutrients are moved from one trophic level to the next (or
along the food chain) by feeding. Some nutrients will be used by the consumer and
some will be lost due to energy expenditure of life processes, movement,
reproduction, healing, recovery, excretion of waste, etc.

●After death, the bodies of producers and consumers are broken down by
decomposers and nutrients are converted back to their basic elements only to
return to the water and then the atmosphere. It truly is one big cycle!

Abiotic =
non-living

Biotic =
living

Multiple Select

What do the terms Abiotic and Biotic mean (select all that apply)

• Abiotic means living

• Abiotic means non-living

• Biotic means living

• Biotic means non-living

3.3.2 Understand that nutrients can include gases such as CO2, ions such as Mg2+, CO3

2-, PO4

3- and

organic compounds such as carbohydrates, lipids & proteins

CO2 dissolves from the atmosphere

Mg2+, CO3

2-, PO4

3- enter via runoff from land

Carbohydrates

Lipids

Protein

3.3.3 State the chemical elements that make up carbohydrates, lipids, and proteins & 3.3.4 State that large molecules are made from smaller
molecules, limited to starch & cellulose from glucose, proteins from amino acids, & lipids from fatty acids & glycerol

Smaller molecules
(monomers)

Chemical elements

Structure

Carbohydrates

Glucose makes
up Starch &
Cellulose

C, H, O

Lipids

Fatty acid,
Glycerol

C, H, O

Protein

Amino acid

C, H, O, N
(sometimes S &
P)

Fill in the Blank

What is the monomer (small molecule) that makes up Cellulose?

3.3.5 Understand that some nutrients supply organisms with a source of essential elements and
these elements have important biological roles

Nutrient

Biological Roles

Nitrogen

Proteins & DNA

Carbon

Proteins, DNA, Carbohydrates/Sugar/Glucose, Lipids/Fats/Oils

Magnesium

To make chlorophyll

Calcium

Bones, shells, & coral skeletons

Phosphorus

DNA, bones, ATP, phospholipid bilayers

Multiple Choice

What is a biological role of Calcium?

• To make coral skeletons

• To make the structure of DNA

• To make chlorophyll

• To make phospholipid bilayers

Multiple Select

What are the biological roles of phosphorous? (select all that apply)

• ATP

• phospholipid bilayers

• DNA

• glucose

3.3.6 Understand that some nutrients are soluble and that there is a reservoir of these nutrients
dissolved in the ocean which is available to producers and consumers

Ion

Mean

concentration in
seawater (ppt)

Chloride

19.345

Sodium

10.752

Sulphate

2.701

Magnesium

1.295

Calcium

0.416

Hydrogencarbonate

0.145

Nutrients enter either
by dissolving from
the atmosphere or via
runoff from land

From the surface
layer, organisms can
take up or absorb
nutrients (producers
& consumers)

Cycle through food
chains through
consumption

The residence time is the average
time a particle spends in a system.

3.3.7 Explain the processes by which the reservoir of dissolved nutrients is replenished, including
upwelling, runoff, tectonic activity, dissolving of atmospheric gases, excretion & decomposition

Upwelling = current that brings cold, nutrient-rich
water to the surface from deep depths/bottom of
the ocean

Runoff = water flowing over land; weathers & erodes
& deposits nutrients in the surface layer

Tectonic activity = Volcanoes & HTV bring sulfur,
hydrogen sulfide, etc.

Dissolving of atmospheric gases: Nitrogen & CO2

Excretion = release of nutrients through feces & sinks
to the sea floor &/or is consumed by other organisms

Decomposition = broken down by bacteria; nutrients
can then be brought back into the food chain/web

Processes That ADD Nutrients to the Surface Water-
3 Main Ways

1.

Dissolving directly into the water from the atmosphere.

●Nitrogen and Carbon are both already in the atmosphere and can be
dissolved directly into the water.

●Amount of gas that can dissolve depends on: water temp,
atmospheric concentration of each gas, and the amount of mixing
of water at the surface.

Sink= Net loss of material (in atmosphere)

Source= Net gain of material (in atmosphere)

Example- Areas where there is more gas
dissolving in the water than diffusing back
into the atmosphere.

Example- Areas where there is more gas
diffused into the atmosphere than is
dissolving into the water.

Dissolving of atmospheric
gases depends on:
●Temperature of water
(lower the temperature,
higher the rate of solubility,
higher temp= lower
solubility).

●Atmospheric concentration
of each gas (How much gas
is present to dissolve into
the water).

●Amount of mixing of water
at the surface (no wind
from strong weather
patterns= no mixing).

Examples of how Carbon is dissolved in the ocean:

Multiple Choice

The higher the temperature, the ________ the rate of solubility of gases.

• lower

• higher

Processes That ADD Nutrients to the Surface
Water- 3 Main Ways

2. Upwelling

●Nutrient-rich animals and plants that have died
and fecal matter sinks to the ocean floor.

●They’re further broken down by decomposers
and nutrient ions are returned to the water.

●Cold water from deep ocean is swept up to the
surface.

●Upwelling is caused by coastal winds that blow
parallel to the shore.

●Productivity is greatly aided by this
phenomenon that brings nutrients to the
surface level.

See the effect of upwelling here:
https://www.youtube.com/watch?v=60_y6-CiUMA

Upwelling increases productivity

Processes That ADD Nutrients to the Surface Water- 3
Main Ways

3.Run-Off

●Part of the water cycle in which water
flows into streams and rivers and from
there to the ocean.

●Water then condenses into clouds and
falls to the land as precipitation.

●When precipitation enters the soil, it is
said to infiltrate it (think of a sponge).

Run-off Continued

●Rate of infiltration is affected by type
of soil. I.e.- Sand=high infiltration,
Clay=low infiltration.

●High infiltration= lower surface run-off;
Low infiltration= high surface run-off.

●As water flows into the sea, it leaches
nutrients from the soil into the sea.

●Other chemicals may also flow into
the ocean from soil: Heavy metals, oil,
pollutants, pesticides, sewage, etc.

●Excess nutrients can lead to dead
zones from over production of algae.

Watch this video on urban runoff to see more on
the problem of runoff pollutants:
https://www.youtube.com/watch?v=5bHGPkxG
V5Q

Multiple Choice

Sand has _____ infiltration and therefore ______ surface run-off.

• high, high

• low, low

• high, low

• low, high

3.3.8 Understand that the reservoir of dissolved nutrients is depleted by uptake into organisms

Producers take up/absorb nutrients

Fishes swallow sea water

Cycle through food chains

Organisms die & sink to the sea floor

Feces sinks to the sea floor

Decomposition occurs

4.4 Processes that REMOVE nutrients from the
surface layer (4 total)

1.

Uptake and assimilation by
producers

Key Points

●Producers fix inorganic ions (suffix
*ate* atom or molecule with a net
electric charge due to the loss or
gain of one or more electrons) into
useable organic compounds that
are fed on by consumers.

Uptake and Assimilation con’t.

●Phytoplankton need nutrients to grow.

●Two critical ones are nitrogen and
phosphorous since they are in low
concentrations in seawater and must
be added by natural processes
(“limiting nutrients”).

●Nitrogen and phosphorous are used to
make proteins, nucleic acids and other
cell parts.

Uptake and Assimilation Steps

1.Phytoplankton take up nitrate (or other) ions and
use them to produce amino acids.

2.The amino acids are built into proteins that form
phytoplankton structures.

3.Zooplankton eat the phytoplankton, digesting the
proteins.

4.Amino acids are released during zooplankton
digestion.

5.This will produce proteins for the zooplankton.

6.Small fish eat the zooplankton.

7.Process repeats itself.

4.4 Processes that REMOVE nutrients from the
surface layer

2. Marine Snow

Key Points

●Small particles of feces and dead animals (organic matter), soot and
inorganic dust that fall down from the surface layer to the deeper
ocean.

●Composed of: Bodies of dead phyto and zooplankton, along with feces
from organisms living in surface layers.

●Marine snow is eaten by filter feeders at the bottom or captured in the
pelagic zones before it hits the bottom by other fish and zooplankton.

●Some nutrients in the marine snow
are released through erosion and
dissolving, or remains in sediment for
years.

●Watch this video to learn more:
https://www.youtube.com/watch?v=
Lt8rDz0vx2o

4.4 Processes that REMOVE nutrients from
the surface layer

3. Incorporation into coral reefs
Key Points

●Coral polyps secrete hard calcium carbonate shells to protect themselves from
the outside world.

●Tiny zooplankton attach to coral and are eaten by it

●Coral polyps come out of their skeletons at night to feed

●Prey are pulled into polyps’ mouths and digested

●Coral obtains nutrients by assimilating them from the zooplankton

Coral Polyp

Nutrients contained in
coral reefs are removed
from the cycling process
for a long time.

Most established coral
reefs are between 5000
and 10,000 years old.

3.3.9 Understand that the nutrients taken up by organisms in food chains can be removed by
harvesting

4. Harvesting

●Removal of marine species by humans, large scale commercial
fishing.

●Global fish catch is approximately 90.9 million metric tons per
year.

○(30% higher than previously thought)

●Plankton, macroalgae (seaweed) and crustaceans (crabs, lobsters,
mollusks/mussels/squid) are removed along with the fish.

●Many nutrients are cycled back into the ocean:

○Fish caught, eaten, and digested by humans will have some
of the nitrogen containing compounds lost to urine

○Some areas return this sewage back to the rivers/ocean

4.4 Processes that REMOVE nutrients
from the surface layer

Multiple Choice

Which are ways that nutrients get depleted?

• excretion

• run-off

• uptake

• tectonic activity

3.3.10 Explain why productivity may be limited by the availability of dissolved nutrients

Feces / carcussses sink to the
sea floor

Decomposition occurs

Will become embedded in the
sediment

Upwelling does not always occur
/ does not occur everywhere

Decomposition occurs slowly in
colder water & in water with less
oxygen

Reservoirs in Nutrient Cycles

●Abiotic phase of a nutrient cycle.

●Elements remain here for long periods of
time, hundreds to thousands of years.

●Residence time is the average time a particle
spends in a system.

●The ocean is a huge reservoir of many
elements.

●Residence time of nutrient ions is so
extensive because they fall to the ocean floor
as feces or dead organisms.

●Remain in ocean floor sediment undisturbed
for thousands to millions of years.

●Nutrients in the surface layer are utilized
much quicker by nearby plants, fish, and
bacteria.

●Surface reservoir is extremely important to
phytoplankton production.

Cycling of Nutrients in the Ocean

Atmosphere & Land

Dissolving
(atmospheric
dissolution)

Runoff

Reservoir at the
surface of the ocean

Uptake / Absorption
Food Chains / Webs

Harvesting

Death, feces, sinking,
decomposition, incorporation
into coral reefs

Sea Floor

Upwelling

Key:
Movement of nutrients
Stored nutrients

3.3.11 Describe the carbon cycle, limited to combustion, photosynthesis, respiration,
decomposition, formation of fossil fuels, formation and weathering of rocks containing carbonate

The Marine Carbon Cycle

●Carbon is the basis for all living things.

●C enters the biotic phase of the cycle through fixation of CO2 in
photosynthesis.

●C is then released through respiration by all living things.

●C enters the ocean by dissociation: Dissolves into the water in the
form of carbonic acid (H2CO3). Then dissociates into 2 additional
forms: hydrocarbonate ions and hydrogen ions in a reversible action.
Hydrogen carbonate then dissociates further into carbonate ions
(pic. right) and hydrogen ions (H+).

●There is a dynamic equilibrium between CO2, hydrogen carbonate,
and carbonic acid.

●In seawater: dissolved inorganic carbon= 89% hydrocarbonate, 10%
carbonate ion, and 1% dissolved carbon dioxide (Carbonic acid).

Multiple Choice

Which phase is Carbon in when it is fixated during photosynthesis?

• Abiotic

• Biotic

Multiple Choice

Which phase of the nutrient cycle is when an element resides in the reservoir for a long period of time?

• Abiotic

• Biotic

https://www.youtube.com/watch?v=6SMWGV-DBnk

Marine Carbon Cycle Cont’d.

●Algae and photosynthetic bacteria can take in dissolved forms
of CO2 to use for photosynthesis that is fixed in glucose.

●Zooplankton that eat producers assimilate carbon into their
own tissue. The same goes for consumers that eat
zooplankton.

●At each stage, organisms are respiring, so carbon is released
back into the the atmosphere.

●When animals die, organic matter is eaten or falls to ocean
floor where it may remain for a long time.

●The ocean and atmosphere exchange 90 gigatons of carbon
per year.

●2 Gigatons are added by human action due mostly to burning
fossil fuels.

●Oceans are becoming overburdened sinks for the additional
carbon. Reduction of species reduces the ocean’s capacity to
dissolve this additional carbon.

****High carbon levels creates a pH imbalance. This imbalance is the main cause of
ocean acidification which has reduced coral reefs recently. ****

This diagram of the fast carbon cycle shows the movement of carbon between land, atmosphere, and oceans. Yellow numbers are natural fluxes, and red are
human contributions in gigatons of carbon per year. White numbers indicate stored carbon. (Diagram adapted from U.S. DOE, Biological and Environmental
Research Information System.)

90 gigatons of
carbon dissolve
into the ocean
and diffuse back
into the
atmosphere
again each year.

An extra 2
gigatons of
carbon each year
are added to
ocean by
combustion of
fossil fuels.

This makes the
ocean a carbon
sink, reducing
atmospheric
carbon dioxide.

Open Ended

Explain the importance of the ocean on reducing emissions in the atmosphere. [3 points]

Scientists have suggested “IRON
FERTILIZATION/SEEDING” as a
means of increasing productivity of
phytoplankton which would then
increase uptake of carbon.

Question: What could be a potential
consequence of this action?

Long-Term Carbon Cycle

●When organic matter falls to the floor as marine snow, it
contains carbonate ions which are also found in corals
and shells of sea animals.

●This fallen organic matter builds up into layers over time
as sediment and eventually becomes sedimentary rock,
such as limestone.

●This process permanently removes carbon from the
carbon cycle.

●The sedimentary rock may eventually become part of a
landmass through marine uplift.

●Marine uplift is a slow gradual process involving plate
tectonic movement or earthquakes.

●When this rock is exposed, it is subjected to erosion and
weathering.

●The carbon that was stored in the rock can then be
released as carbon dioxide through chemical weathering.

Long-Term Carbon Cycle Cont.

●Another part of the long-term carbon cycle is the
formation of fossil fuels.

●Coal is formed from dead plants whereas oil and
gas are formed from organic matter which falls
to the bottom of the ocean to form sediment.

●Sometimes sediment is buried in mud, as mud
layer gets thicker, it is subjected to heat and
pressure from Earth’s core, changing chemical
structure and forms fossil fuels. This takes
approximately 650 million years.

●Carbon is returned when fossil fuels are burned.

●Combustion is quicker than formation of fossil
fuels so can lead to an imbalance of carbon
dioxide in the atmosphere.