Lecture 11 Production

Ecosystem

all the components of an ecological system, biotic and abiotic, that influence the flow of energy and elements

Primary production

chemical energy generated by autotrophs during photosynthesis and chemosynthesis

Primary productivity

the rate of primary production (g C per area per time)

Gross primary production

total amount of carbon fixed by autotrophs

Leaf area index

leaf area per unit of ground area

What is this graph showing?

higher LAI = higher CO₂ uptake, and that CO₂ uptake varies throughout day bc of sunlight availability

Net primary production

GPP – Respiration, Amount of energy captured that results in an increase in biomass

What are these graphs showing? • What are the reasons for the changes in carbon flux?

young forests increase carbon uptake as they grow, but older forests generally have lower net primary productivity (NPP) because growth slows and respiration increases relative to photosynthesis.

Secondary production

Energy derived from consuming organic compounds produced by other organisms

Net secondary production

Ingestion – Respiration – Egestion