The influence of sea ice cover on microbial community structure and diversity in the Barents Sea

Thinner and reduced sea ice cover in the Arctic are predicted to impact the quality and quantity of dissolved organic matter, in turn influencing the community composition, structure, diversity and activity of heterotrophic microbes that utilise this carbon pool, recycling the DOM within the water column. To assess the influence of varying sea ice cover on microbes, 16S rRNA gene sequence data was obtained from water column samples collected during a series of ship-board sampling campaigns in the Barents Sea. As part of the Changing Arctic Ocean programme, in July of 2017, 2018 and 2019, the RSS James Clark Ross followed a North-South transect off the east coast of Svalbard. Six core stations were sampled each year, with additional samples occurring in 2018 and 2019, dependent on sea ice coverage. Samples were taken from a range of depths in the water column. For each depth sampled, 2 L of seawater was filtered through a 0.22 micron sterivex filter unit using a peristaltic pump. DNA were extracted using an AllPrep DNA/RNA kit (Qiagen, Manchester, UK) following the instructions of the manufacturers. 16S rRNA genes (V4 region) were amplified using the PCR primers 515F and 806R. Sequencing was performed on the MiSeq Personal Sequencer (Illumina, San Diego, CA, USA) using the V2 500 reagent kit by commercial contract (NU-OMICS, Northumbria, UK).