Heterotrophs must feed on other organisms to obtain energy. Primary production is the creation of new organic matter by plants and other autotrophs. It can be measured per unit area for individual ecosystems or worldwide. Production also is measured per time unit, while standing crop biomass is the amount of plant matter at a given point in time. Production can be quantified by a simple process by which oxygen or carbon production is measured.
Production varies among ecosystems, as well as over time within ecosystems.
Rates of production are determined by such factors as climate and nutrient supply. Links Send feedback to the Global Change Webmaster .