How Rapidly Do Producers in Different Ecosystems Produce Biomass?
The rate at which an ecosystem’s producers convert solar energy into chemical energy as biomass is the ecosystem’s gross primary productivity (GPP). However, to stay alive, grow, and reproduce, an ecosystem’s producers must use some of the total biomass they produce for their own respiration. Only what is left, called net primary productivity (NPP), is available for use as food by other organisms (consumers) in an ecosystem: Net primary productivity Rate at which producers storechemical energy as biomass (produced by photosynthesis) Rate at which producers use chemical energy stored as biomass (through aerobicrespiration) Net primary productivity is the- rate at which energy for use by consumers is stored in new biomass (cells, leaves, roots, and stems).Various ecosystems and life zones differ in their NPP (Figure 2-23). The most productive are (1) estuaries, (2) swamps and marshes, and (3) tropical rain forests. The least productive are (1) open ocean, (2) tundra (arctic and alpine gr
