(GPP) Gross and net primary productivity of an ecosystem
An ecosystem’s gross primary productivity (GPP) is the total amount of organic matter that it produces through photosynthesis.
Net Primary productivity
Net Primary productivity (NPP) describes the amount of energy that remains available for plant growth after subtracting the fraction that plants use for respiration. Productivity in land ecosystem generally rises with temperature up to about 30◦C, after which is declines, and is positively correlated with moisture. On land primary productivity thus is highest in warm, wet zones in the tropics where tropical forest biomes are located.
why do deserts have low productivity
In contrast, desert scrub ecosystem have the lowest productivity because their climates are extremely hot and dry.
Factors affecting primary productivity in oceans
In the oceans, light and nutrients are important controlling factors for productivity. “Oceans,” light penetrates only into the uppermost level of the oceans, so photosynthesis occurs in surface and near-surface waters.
Marine ecosystem primary productivity
Marine primary productivity is high near coastlines and other areas where upwelling brings nutrients to the surface, promoting plankton blooms.
which is the primary source of nutrients for estuaries
Runoff from land is also a source of nutrients is estuaries and along the continental shelves. Among aquatic ecosystems, algal beds and coral reefs have the highest net primary production, while the lowest rates occur in the open due to a lack of nutrients in the illuminated surface layers.
In contrast to land, where vascular plants carry out most primary production, most primary production in the oceans in done by microscopic algae.
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