Seasonality of microbial genetic functions in the Arctic Ocean revealed by autonomous sampling

• Main Authors: Priest, Taylor, Fuchs, Bernhard, Amann, Rudolf, Boetius, Antje, Wietz, Matthias
• Format: Conference Object
• Language: unknown
• Published: 2022
• Subjects: Arctic; Arctic Ocean; Climate change; East Greenland; east greenland current; Fram Strait; Greenland; Phytoplankton; polar night; Spitsbergen
• Online Access: https://epic.awi.de/id/eprint/56141/; https://epic.awi.de/id/eprint/56141/1/osm2022_MWietz.pdf; https://osm2022.secure-platform.com; https://hdl.handle.net/10013/epic.1c4dc718-b5d5-47bd-b85a-b06d98f8bcae

The functional diversity of microbes along the seasonal extremes in the Arctic Ocean including the Polar Night are virtually unknown. Here, using PacBio long-read metagenomes derived from automated samplers over an annual cycle, we elucidate functional microbial seasonality in the Fram Strait in the context of a high-resolution amplicon time-series. In the ice-free West Spitsbergen Current, the transition from the phototrophy-dominated spring and summer ecosystem states to the dark winter was evident in bacterial genomes. Proteorhodopsin- and DMSP-utilizing genes peaked in late summer, marking a transition phase. Winter mixing of the water column covaried with microbial taxa encoding ammonia- and urea-metabolizing genes, with probable implications for nitrogen recycling and the following phytoplankton bloom. In the ice-covered East Greenland Current, functional diversity varied with the extent of ice cover and polar water masses. During intermittent low-ice conditions in winter, the metagenomic repertoire resembled that during summer, indicating rapidly (i.e. within weeks) shifting ecosystem states with ice cover. Overall, we provide a baseline to understand ecological and biogeochemical processes in a region severely affected by climate change, with implications for the present and future Arctic Ocean.