ENVS200 Lecture Notes - Lecture 11: Limiting Factor, Autotroph, Herbivore
12 Apr 2018
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Chapter 11: the flux of energy and matter through ecosystems. Standing crop: the bodies of the living organisms within a unit area constitute a standing crop of biomass. Primary productivity: primary productivity is the rate at which biomass is produced per unit area or volume through photosynthesis. Ecologists consider both gross primary productivity and net primary productivity. Gross primary productivity (gpp): gross primary productivity is the total fixation of energy by photosynthesis. A proportion of this, however, is respired away by the primary producer organisms (the autotrophs) themselves and is lost from the ecosystem as respiratory heat (rauto). Net primary productivity (npp): this is the difference between gpp and rauto. It represents the actual rate of production of new biomass that is available for consumption by heterotrophic organisms (bacteria, fungi, and animals). Secondary productivity: by secondary productivity we mean the rate of production of biomass by heterotrophs.
