Genome reconstructions indicate the partitioning of ecological functions inside a phytoplankton bloom in the Amundsen Sea Polynya, Antarctica

Phytoplankton blooms are an ecologically important yet not entirely understood phenomenon. This is certainly the case for the massive Phaeocystis blooms in climate-sensitive Antarctic polynyas. They interact with the atmosphere through the exchange of carbon dioxide and dimethylsulfide. They also sustain a distinct bacterial community that might play a role in bloom duration and intensity. Here we deeply sequenced a metagenome from an Amundsen Sea polynya bloom event and determined the genomic content of bacterial populations surrounding Phaeocystis. A pico-eukaryote genome (19.6 Mb) was also recovered. The identification of functional complementarities between P. antarctica and bacterial taxa organized in close association with Phaeocystis colonies makes a contribution to our understanding of bloom functioning in the Southern Ocean.