The Biological Productivity of the Ocean

Ocean productivity largely refers to the production of organic matter by “phytoplankton,” plants suspended in the ocean, most of which are single-celled. Phytoplankton are “photoautotrophs,” harvesting light to convert inorganic to organic carbon, and they supply this organic carbon to diverse “heterotrophs,” organisms that obtain their energy solely from the respiration of organic matter. Open ocean heterotrophs include bacteria as well as more complex singleand multi-celled “zooplankton” (floating animals), “nekton” (swimming organisms, including fish and marine mammals), and the “benthos” (the seafloor community of organisms).