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Overview. Net ecosystem production describes the total carbon in an ecosystem that can be stored, exported, or oxidized back into carbon dioxide gas. NEP is written in units of mass of carbon per unit area per time, for example, grams carbon per square meter per year (g C m −2 yr −1). In a given ecosystem, carbon quantified as net ecosystem ...
In ecology, the term productivity refers to the rate of generation of biomass in an ecosystem, usually expressed in units of mass per volume (unit surface) per unit of time, such as grams per square metre per day (g m −2 d −1). The unit of mass can relate to dry matter or to the mass of generated carbon. The productivity of autotrophs, such ...
Gross primary production (GPP) is the amount of chemical energy, typically expressed as carbon biomass, that primary producers create in a given length of time.Some fraction of this fixed energy is used by primary producers for cellular respiration and maintenance of existing tissues (i.e., "growth respiration" and "maintenance respiration").
Amounts of productivity are also dependent on the overall capacity of plants to capture sunlight which is directly correlated with plant leaf area and N content. Net primary productivity (NPP) is the primary measure of biomass accumulation within an ecosystem. Net primary productivity can be calculated by a simple formula where the total amount ...
Gross primary productivity is the amount of energy the producer actually gets. [13] [14] Generally, 60% of the energy that enters the producer goes to the producer’s own respiration. [12] The net primary productivity is the amount that the plant retains after the amount that it used for cellular respiration is subtracted. [13]
Primary production can be broken down into gross and net primary production. Gross primary production is a measure of the energy that a photoautotroph harvests from the sun. Take, for example, a blade of grass that takes in x joules of energy from the sun. The fraction of that energy that is converted into glucose reflects the gross ...
Stream metabolism, often referred to as aquatic ecosystem metabolism in both freshwater (lakes, rivers, wetlands, streams, reservoirs) and marine ecosystems, includes gross primary productivity (GPP) and ecosystem respiration (ER) and can be expressed as net ecosystem production (NEP = GPP - ER). Analogous to metabolism within an individual ...
The organisms responsible for primary production are called primary producers or autotrophs. Most marine primary production is generated by a diverse collection of marine microorganisms called algae and cyanobacteria. Together these form the principal primary producers at the base of the ocean food chain and produce half of the world's oxygen.