CENPERM seminar – University of Copenhagen

CENPERM seminar

Bacterial communities hitching a hike – a guide to the river system of the Red River, Disko Island, Greenland

Aviaja Lyberth Hauptmann, PhD student. Novo Nordisk Foundation Center for Biosustainability, DTU/CENPERM

Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on Disko Island, West Greenland (69°N). We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms and more psychrophilic taxa were found in the dominant community supplied by the lake. At the river mouth, the dominant bacterial communities from the lake and glacier were unnoticeable but became evident again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from the river. Environmental variables showed only weak correlations with community composition.

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