AICE Marine Science Unit 4: Nutrient Cycles in Marine Ecosystems

reservoir

part of the abiotic phase of the nutrient cycle where nutrients can remain for a long period of time

upwelling

The movement of dense, cold, nutrient-rich water to the surface from deep in the ocean; caused by winds and geomorphology; adds to reservoir of nutrients in surface layer of ocean

runoff

Part of the water cycle where an excess of water from precipitation flows from land rather than infiltrates into the soil; eventually makes it to the rivers, lakes, and oceans; carries pollutants and nutrients; adds to reservoir of nutrients in surface layer of ocean

atmospheric dissolution

when gases within the atmosphere (oxygen, carbon dioxide, nitrogen) are added to sea water through the process of diffusion; aided by wave action/turbulence of the sea; adds to reservoir of nutrients in surface layer of ocean

uptake

a process of taking up or using up or consuming nutrients by organisms in a food chain; depletes reservoir of nutrients in surface layer of ocean

productivity

the rate of production of new biomass by an individual, population, or community; the fertility or capacity of a given habitat or area; primarily determined by available resources (i.e. nutrients)

incorporation

The union of one substance with another or with others, in a composite mass; making something part of a whole

harvesting

removal of organisms from an environment, ex. fishing

nitrogen (biological use)

creation of proteins, DNA

carbon (biological uses)

makes all organic materials, biomolecules/macromolecules (carbohydrates, proteins, lipids, nucleic acids)

magnesium (biological uses)

Creation of chlorophyll

Calcium (biological uses)

creation of bones, corals, shells

Phosphorous (biological uses)

creation of DNA and bone

Carbon cycle

Carbon enters the ocean by dissolving from the atmosphere and by runoff. Producers use carbon in photosynthesis to form organic molecules. Carbon is returned by respiration, decomposition, and sinking matter. Upwelling brings carbon back to the surface. Burning fossil fuels adds more carbon and causes ocean acidification.

nitrogen cycle

Nitrogen enters from the atmosphere, runoff, and upwelling. Bacteria convert nitrogen gas to usable forms like nitrates. Producers use it for proteins and DNA. Nitrogen is recycled when organisms die and decompose. It is quickly used up in the surface layers of the ocean.

magnesium cycle

Magnesium comes from rocks and runoff. It is needed to make chlorophyll for photosynthesis. It cycles through food chains and decomposition. Magnesium has a long residence time, so its levels stay steady in seawater.

Calcium cycle

Calcium enters from rocks and runoff. It is used by organisms for shells, bones, and coral skeletons. When organisms die, shells sink and can form limestone. Upwelling and weathering return calcium to the cycle. Levels stay fairly constant, but ocean acidification dissolves calcium carbonate.

Phosphorous Cycle

Phosphorus comes from the weathering of rocks and runoff. It is used for DNA, ATP, and membranes. It cycles through food chains and decomposition, and can sink to the seabed as sediments. Fertilizer runoff adds extra phosphorus and can cause eutrophication.

Simplified Nutrient Cycle that can be applied to all major marine nutrients

nutrient

chemical substance that provides what is needed for an organism to sustain life and grow

decomposers

bacteria and fungi that break down dead organic matter (i.e. wastes and dead organisms) and return nutrients back into the environment

abiotic

the environment's geological, physical and chemical features, the non-living part of an ecosystem

biotic

the living parts of an ecosystem; includes organisms and their effects on each other

assimilation

the conversion of a nutrient into a useable form that can be incorporated into the tissues of an organism

residence time

the average time that a particle spends in a particular system

processes that add nutrients to reservoir at ocean surface

runoff, dissolution, upwelling

factors that remove nutrients from reservoir at ocean surface

uptake & assimilation; sinking/marine snow; harvesting; incorporation by coral reefs

sink

an area where there is a net loss of material (i.e. where more gas dissolves into the ocean than diffuses into the atmosphere)

source

an area where there is a net gain of material (i.e. where more gas diffuses into the atmosphere than dissolves into the ocean)

infiltration

part of the water cycle where water soaks into the soil from ground level and moves underground

leaching

a process during which water-soluble nutrients are removed from the soil and dissolve in water that is flowing to the sea (runoff)

marine snow

Particles of organic material that fall from surface waters to the deeper ocean

dissociation (dissociates)

a reversible chemical change where the molecules of a single compound separate into two or more other substances

limiting factor

Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.

nitrogen fixation

the chemical processes by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle

ecosystem

A biological community of interacting organisms and their physical environment.

detritus

Nonliving organic matter such as remains of dead organisms, feces

Nutrient Cycle AKA Biogeochemical cycle

The movement of abiotic factors (nutrients) between the living and nonliving components within ecosystems

depletion

The use or consumption of a resource, especially a natural resource, faster than it is replenished.