A MODEL FOR THE SIZE-FRACTIONATED BIOMASS AND PRODUCTION OF MARINE-PHYTOPLANKTON

Mathematical relationships are developed to derive potential export (i.e. sedimentation, grazing, or advection) from the proportions of production and biomass in two size fractions of phytoplankton. Size-fractionated data (540 points) from 40 published studies are plotted on a production-biomass diagram, from which potential export is predicted. The predictions are supported by published information. Six ecological domains are defined from the positions of data points on the production-biomass diagram: equatorial/tropical oceanic, tropical neritic, and subtropical oceanic waters, oceanic North Atlantic, Southern Ocean, and upwelling areas together with coastal northwest Atlantic blooms. The resulting picture is coherent especially when the heterogeneity of data sources is considered.