net primary productivity

…of producers; what remains is net productivity. Net marine primary productivity is the amount of organic material available to support the consumers (herbivores and carnivores) of the sea. The standing crop is the total biomass (weight) of vegetation. Most primary productivity is carried out by pelagic phytoplankton, not benthic plants.

…of energy fixed by photosynthesis—and net primary production—i.e., the amount of energy fixed less that respired by the plants involved and available for secondary production. Note that forms of production using energy other than radiant energy from the Sun are not important to overall aquatic production (see above marine ecosystem:…

…used by plants is called net primary productivity, and it is this remainder that is available to various consumers in the ecosystem—e.g., the herbivores, decomposers, and carnivores. Of course, in any stable ecosystem there is neither an accumulation nor a diminution in the total amount of organic matter present, so…

…have relatively high levels of net primary productivity compared with the actual biomass (dry mass of organic matter) of the vegetation at any one time. (For a full discussion of productivity, see biosphere: The photosynthetic process.) Most of this productivity is concentrated into the period during and following the wet…

…mainly through photosynthesis is called net primary production or NPP and is the dominant source of food, fuel, fibre, and feed for the entire population of Earth. Approximately 55 billion metric tons (61 billion tons) of carbon are stored in this way each year worldwide, most of it in forests.…

…further use and is called net primary productivity. About 40 to 85 percent of gross primary productivity is not used during respiration and becomes net primary productivity. The highest net primary productivity in terrestrial environments occurs in swamps and marshes and tropical rainforests; the lowest occurs in deserts. In aquatic…

Net primary productivity, gross primary productivity less that used by plants in respiration, is approximately 10 metric tons per hectare per year; it is greatest in young forests where the trees are rapidly growing toward full size, and it declines in forests of old trees.…