State of the Arctic Marine Biodiversity Report: chapter 3.2: Plankton

Plankton chapter of the State of the Arctic Marine Biodiversity Report covering four Focal Ecosystem Components: Bacteria and Archaea, microbial eukaryotes, phytoplankton, and zooplankton.

Plankton refers to taxonomically and functionally diverse aquatic organisms that range in size from submicron (1 ¼m) to centimetres (cm). They share a limited ability to control their ocation against oceanic currents. Phytoplankton are responsible for all primary production in the open ocean and are the base of the pelagic food chain supporting higher trophic levels. Arctic phytoplankton and other protists, which include single-celled micro zooplankton, are the main food for copepods that are the principal food for larger macrozooplankton, and some species of fish and seabirds. Bacterioplankton are essential for degrading organic carbon in the ecosystem, and in the open ocean, including the Arctic, Bacteria and Archaea are responsible for remineralization of nutrients. Heterotrophic and mixotrophic microbial eukaryotes graze on Bacteria and Archaea as well as smaller phytoplankton. All of these single-celled plankton are subject to strong environmental selection.