gross_primary_mole_productivity_of_biomass_expressed_as_carbon_by_diatoms mol m-2 s-1 [M2MS] Gross primary production is the rate of synthesis of biomass from inorganic precursors by autotrophs ("producers"), for example, photosynthesis in plants or phytoplankton. The producers also respire some of this biomass and the difference is "net_primary_production". "Productivity" means production per unit area. "Production of carbon" means the production of biomass expressed as the mass of carbon which it contains. The phrase "expressed_as" is used in the construction "A_expressed_as_B", where B is a chemical constituent of A. It means that the quantity indicated by the standard name is calculated solely with respect to the B contained in A, neglecting all other chemical constituents of A.
Diatoms are phytoplankton with an external skeleton made of silica.
Phytoplankton are algae that grow where there is sufficient light to support photosynthesis.