A metagenomic assessment of winter and summer bacterioplankton from Antarctic Peninsula coastal surface waters

• Published in: The ISME Journal
• Main Authors: Grzymski, J, Riesenfeld, C, Williams, TJ, Dussaq, A, Ducklow, H, Erickson, M, Cavicchioli, R, Murray, A
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: International Society for Microbial Ecology 2012
• Subjects: 14 Life Below Water; Antarctic Regions; Archaea; Autotrophic Processes; Bacteria; DNA; Archaeal; Bacterial; Gene Library; Heterotrophic Processes; Metagenomics; Phylogeny; Plankton; RNA; Ribosomal; Seasons; Seawater; Sequence Analysis; anzsrc-for: 060504 Microbial Ecology; anzsrc-for: 05 Environmental Sciences; anzsrc-for: 06 Biological Sciences; anzsrc-for: 10 Technology; Antarc*; Antarctic; Antarctic Peninsula; Sea ice; Southern Ocean
• Online Access: http://hdl.handle.net/1959.4/unsworks_49920; https://unsworks.unsw.edu.au/bitstreams/a90c4a23-39ed-48be-b1f1-0049a2f47043/download; https://doi.org/10.1038/ismej.2012.31

Antarctic surface oceans are well-studied during summer when irradiance levels are high, sea ice is melting and primary productivity is at a maximum. Coincident with this timing, the bacterioplankton respond with significant increases in secondary productivity. Little is known about bacterioplankton in winter when darkness and sea ice cover inhibit photoautotrophic primary production. We report here an environmental genomic and SSU rRNA analysis of winter and summer Antarctic Peninsula coastal seawater bacterioplankton. Intense inter-seasonal differences reflected through shifts in community composition and functional capacities encoded in winter and summer environmental genomes with significantly higher phylogenetic and functional diversity in winter. In general, inferred metabolisms of summer bacterioplankton were characterized by chemoheterotrophy, photoheterotrophy and aerobic anoxygenic photosynthesis while the winter community included the capacity for bacterial and archaeal chemolithoautotrophy. Chemolithoautotrophic pathways are dominant in winter and are similar to those recently reported in global ‘dark ocean’ mesopelagic waters. If chemolithoautotrophy is widespread in the Southern Ocean in winter, this process may be a previously unaccounted for carbon sink and may help account for unexplained anomalies in surface inorganic nitrogen content.