Bacterial community structure and functional profiling of high Arctic fjord sediments

Kongsfjorden, an Arctic fjord is significantly affected by the glacier melt and Atlantification, both the processes driven by accelerated warming in the Arctic. This has lead to changes in primary production, carbon pool and microbial communities, especially that in the sediment. In this study, we have examined the bacterial community structure of surface (0-2 cm) and subsurface (3-9 cm) sediments of Kongsfjorden using the high throughput sequencing analysis. Results revealed that bacterial community structure of Kongsfjorden sediments were dominated by phylum Proteobacteria followed by Bacteroidetes and Epsilonbacteraeota. While alpha- and gamma-Proteobacterial class were dominant in surface sediments; delta-Proteobacteria were found to be predominant in subsurface sediments. The bacterial community structure in the surface and subsurface sediments showed significant variations (p <= 0.05). Total organic carbon could be one of the major parameters controlling the bacterial diversity in the surface and subsurface sediments. Functional prediction analysis indicated that the bacterial community could be involved in the degradation of complex organic compounds such as glycans, glycosaminoglycans, polycyclic aromatic hydrocarbons and also in the biosynthesis of secondary metabolites.

Automated summary

Kongsfjorden, an Arctic fjord, is experiencing changes in bacterial community structure of sediments due to glacier melt and Atlantification driven by accelerated warming in the Arctic. The dominant phyla in the sediments are Proteobacteria, Bacteroidetes, and Epsilonbacteraeota, with alpha- and gamma-Proteobacteria class dominating in surface sediments and delta-Proteobacteria in subsurface sediments. Total organic carbon is suggested to be a major factor affecting bacterial diversity, and bacterial communities are predicted to be involved in the degradation of complex organic compounds and biosynthesis of secondary metabolites.