IB ESS 2.3: Flows of Energy and Matter

primary

to do with plants

secondary

to do with animals

gross

the total amount of something

net

the amount left after deductions

biomass

the living mass of an organism

productivity

conversion of energy into biomass over a period of time. It is the rate of growth or biomass increase in plants and animals

gross productivity

the total gain in energy or biomass

the biomass that could be gained by an organism before deductions

net productivity

the gain in energy or biomass

the biomass that remains after deductions

(this value is always smaller than the GP)

gross primary productivity

the total gain in energy or biomass by green plants

the energy gixed by green plants by photosynthesis

net primary productivity

the total gain in energy or biomass by green plans after respiration loss

gross secondary productivity

the total gain in energy/biomass taken up by consumers (when animals eat plants)

net secondary productivity

the total gain in energy/biomass by consumers after allowing for respiration loss

biogeochemical cycle

a pathway by which a chemical substance moves through both the biotic and abiotic components of Earth (cycling of substances).

carbon fixation

the incorporation of carbon into organic compounds by living organisms, chiefly by photosynthesis in green plants.

nitrogen fixation

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

nitrification

the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate.

denitrification

the loss or removal of nitrogen or nitrogen compounds; specifically: reduction of nitrates or nitrites commonly by bacteria (as in soil) that usually results in the escape of nitrogen into the air.

decomposition

the state or process of rotting; decay.

assimilation

the absorption and digestion of food or nutrients by the body or any biological system.

energy budget

a balance sheet of energy income against expenditure. It is studied in the field of Energetics which deals with the study of energy transfer and transformation from one form to another.

trophic efficiency

describes the efficiency with which energy is transferred from one trophic level to the next.

energy subsidy

the additional energy we have to input into the system which comes from the Sun's energy

maximum sustainable yield

the largest crop that can be taken from the stock of a species without depleting the stock. Taken away is the increase in production of the stock while leaving the stock to reproduce again.

efficiency of assimilation

gross productivity X 100/food eaten

efficiency of biomass productivity

net productivity X 100/gross productivity

carbon cycle

the series of processes by which carbon compounds are interconverted in the environment, involving the incorporation of carbon dioxide into living tissue by photosynthesis and its return to the atmosphere through respiration, the decay of dead organisms, and the burning of fossil fuels.

nitrogen cycle

the series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms, including nitrogen fixation and decomposition.