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

Carbon sinks

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

Flows in carbon cycle

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

Flows in nitrogen cycle

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

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

Nitrogen will leave the ecosystem in one of 3 ways:

* **denitrification**
* **Leaching**
* **Combustion**

leaching

**Leaching** may dissolve the soluble nitrates and wash them out of the soil.

combustion

releases nitrogen locked up in organic material as nitrogen oxide or nitrogen dioxide

Fossil fuel combustion and forest fires increases…..

nitrogen oxides

__Ecotones__

Transitional zones between biomes