Energy and Ecosystems

Producer

An organism that makes its own organic molecules using water, CO₂ and light energy

Trophic level

The position an organism occupies in a food chain

Biomass

Total mass of living material in organism, measured in dry mass

Gross primary production (GPP)

• The chemical energy store in plant biomass, in a given area or volume

• (Total energy entering food chain from photosynthesis)

Net Primary Production (NPP)

The chemical energy store in plant biomass taking into account the energy that will be lost due to respiration

Net Primary Production equation

NPP = GPP- Respiration energy

Net Production of consumers formula

N = I - (F + R)

• N=Net production of consumers

• I=Chemical energy store in ingested food

• R=Respiratory energy losses

• F=Chemical energy lost to environment in faeces and urine

Units of rates of productivity

kJ ha^-1 year^-1