Phytoplankton dynamics in a changing Arctic Ocean

Changes in the Arctic atmosphere, cryosphere and Ocean are drastically altering the dynamics of phytoplankton, the base of
marine ecosystems. This Review addresses four major complementary questions of ongoing Arctic Ocean changes and associated
impacts on phytoplankton productivity, phenology and assemblage composition. We highlight trends in primary production
over the last two decades while considering how multiple environmental drivers shape Arctic biogeography. Further, we
consider changes to Arctic phenology by borealization and hidden under-ice blooms, and how the diversity of phytoplankton
assemblages might evolve in a novel Arctic ‘biogeochemical landscape’. It is critical to understand these aspects of changing
Arctic phytoplankton dynamics as they exert pressure on marine Arctic ecosystems in addition to direct effects from rapid
environmental changes.