As the basis of the marine food web, phytoplankton is comprised of a great variety of living, planktonic, unicellular algae in the ocean. In high-latitude environments, particularly in the Southern Ocean, the Arctic Ocean and areas in their vicinity, phytoplankton is responsible for providing food to animals and bacteria in the form of newly synthesized organic carbon. Different from plankton at lower latitudes where bacteria and dissolved organic carbon dominate, most of the organic carbon in surface waters of polar oceans during the growth season is in particulate form, and dominated by phytoplankton biomass.
Ecology of polar phytoplankton includes a diverse line of topics, from description of species within plankton assemblages or community diversity, determination of biological processes of phytoplankton production and loss rates to understand their contribution to the carbon cycle, the temporal and spatial variability of a particular species or total biomass and their relationship to environmental forces, experimenting with radiation or nutrients to interpret phytoplankton distribution in relationship to water masses or stratification from surface to deeper waters which contributes to our ability to predict their responses to light quality and quantity, relating phytoplankton abundance composition to carbon availability to benthic communities. Studies particular to polar phytoplankton are algae growth at low temperature and adaptation to low or not light in the winter, exchange of algae between sea ice and surface waters and determination of communities associated with the sea ice edge or free-floating icebergs.