Sub-Topic 2.3 Flows of Energy and Matter

Insolation

solar radiation

Productivity

the conversion of energy into biomass for a given period of time

Net Primary Productivity (NPP)

Gross primary productivity minus respiration losses (GPP - R)

Net secondary productivity (NSP)

calculated by subtracting respiratory losses (R) from GSP (NSP = GSP - R).

Gross secondary productivity (GSP) = Assimilation

Gross secondary productivity is the total energy or biomass assimilated by consumers and is calculated by subtracting the mass of fecal losses from the mass of food consumed (Food eaten - fecal loss)

Maximum sustainable yield

equivalent to the net primary or net secondary productivity of a system, highest rate of harvesting that does not lead to a reduction in the original capital

sustainable yield

rate of increase in natural capital than can be exploited without depleting the original stock or its potential replenishment

Carbon sinks

stores in a system containing a lot of carbon, e.g. a forest or a peat bog

storages in the carbon cycle

atmosphere, organisms, ocean, soil, fossil fuels

Flows in carbon cycle

consumption (feeding), death and decomposition, photosynthesis, respiration, dissolving, transpiration and fossilization

storages in the nitrogen cycle

atmosphere, organisms, soil, fertiliser, water bodies

Flows in nitrogen cycle

nitrogen fixation by bacteria and lightning, absorption, assimilation, consumption (feeding), excretion, death and decomposition, denitrification by bacteria, fossilization

Human activities impacting carbon and nitrogen cycles

burning fossil fuels, deforestation, urbanisation, agriculture

nitrogen fixation

the conversion of nitrogen gas (N2) into compounds containing nitrates

denitrification

the conversion of nitrogen containing compounds into Nitrogen gas. This happens in water logged soil by anaerobic bacteria

Primary productivity

the gain by producers (autotrophs) in energy or biomass per unit per unit time

Secondary productivity

biomass gained by heterotrophic organisms through feeding and absorption, measured in units of mass or energy

Gross productivity (GP)

total gain in biomass

Net productivity (NP)

gain in energy or biomass remaining after allowing for respiratory losses

Gross primary productivity (GPP)

the mass of glucose created by photosynthesis in primary producers

biomass

renewable organic material that comes from plants and animals