AUTHOR=Thiele Stefan , Vader Anna , Thomson Stuart , Saubrekka Karoline , Petelenz Elzbieta , Müller Oliver , Bratbak Gunnar , Øvreås Lise 

TITLE=Seasonality of the bacterial and archaeal community composition of the Northern Barents Sea

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1213718

DOI=10.3389/fmicb.2023.1213718

ISSN=1664-302X

ABSTRACT=<p>The Barents Sea is a transition zone between the Atlantic and the Arctic Ocean. The ecosystem in this region is highly variable, and a seasonal baseline of biological factors is needed to monitor the effects of global warming. In this study, we report the results from the investigations of the bacterial and archaeal community in late winter, spring, summer, and early winter along a transect through the northern Barents Sea into the Arctic Ocean east of Svalbard using 16S rRNA metabarcoding. Winter samples were dominated by members of the SAR11 clade and a community of nitrifiers, namely <italic>Cand</italic>. Nitrosopumilus and LS-NOB (<italic>Nitrospinia</italic>), suggest a prevalence of chemoautotrophic metabolisms. During spring and summer, members of the <italic>Gammaproteobacteria</italic> (mainly members of the SAR92 and OM60(NOR5) clades, <italic>Nitrincolaceae</italic>) and <italic>Bacteroidia</italic> (mainly <italic>Polaribacter, Formosa</italic>, and members of the NS9 marine group), which followed a succession based on their utilization of different phytoplankton-derived carbon sources, prevailed. Our results indicate that Arctic marine bacterial and archaeal communities switch from carbon cycling in spring and summer to nitrogen cycling in winter and provide a seasonal baseline to study the changes in these processes in response to the effects of climate change.</p>