Bacterial community structure of a glacio-marine system in the Arctic (Ny-Ålesund, Svalbard)

Femi Anna Thomas; Rupesh Kumar Sinha; K P Krishnan

doi:10.1016/j.scitotenv.2019.135264

Bacterial community structure of a glacio-marine system in the Arctic (Ny-Ålesund, Svalbard)

Sci Total Environ. 2020 May 20:718:135264. doi: 10.1016/j.scitotenv.2019.135264. Epub 2019 Nov 23.

Authors

Femi Anna Thomas¹, Rupesh Kumar Sinha², K P Krishnan³

Affiliations

¹ National Centre for Polar and Ocean Research, Headland Sada, Vasco da Gama, Goa 403804, India; School of Earth, Ocean and Atmospheric Sciences, Goa University, Taleigao Plateau Goa 403206, India.
² National Centre for Polar and Ocean Research, Headland Sada, Vasco da Gama, Goa 403804, India.
³ National Centre for Polar and Ocean Research, Headland Sada, Vasco da Gama, Goa 403804, India. Electronic address: kpkrishnan@gmail.com.

PMID: 31848061
DOI: 10.1016/j.scitotenv.2019.135264

Abstract

The bacterial community composition of a valley glacier in Svalbard, its pro-glacial channels, and the associated downstream fjord ecosystem was investigated so as to figure out the degree to which downslope transport of microbes from the glacier systems along a hydrological continuum impose an effect on the patterns of diversity in the fjord system. A combination of culture based and high-throughput amplicon sequencing approach was followed which resulted in significant variation (R = 0.873, p = 0.001) in the bacterial community structure between these ecosystems. Dominance of sequences belonging to class β-Proteobacteria was seen in the glacier snow, ice and melt waters (MW) while a relatively higher abundance of OTUs belonging to α-Proteobacteria and Verrucomicrobiae demarcated the fjord waters. Similarity percentage (SIMPER) analysis of the Operational Taxonomic Units (OTUs) showed that OTU 1,105,280 (9.15%) and OTU 331 (6.5%) belonging to Burkholderiaceae (β-proteobacteria) and OTU 101,660 (5.76%) and OTU 520 (5.07%) belonging to Rhodobacteraceae (α-proteobacteria) contributed maximum to the overall dissimilarity between the sampling sites. The bacterial community from the MWs were found to be true signatures of the glacier ecosystem while the Kongsfjorden bacterial fraction mostly represented heterotrophic marine taxa influenced by warm Atlantic waters and presence of organic matter. Significant presence of unknown taxa in the MWs suggests the need to study such unexplored, transient niches for a better understanding of the associated microbial processes. Among the various environmental parameters measured, nutrients (NO₃^- and SiO₄^2-) were found to exhibit strong association with the MW bacterial community while temperature, trace metals, Cl^- and SO₄^2- ions were found to influence the fjord bacterial community. The significant differences in the bacterial community composition between the glacier and the fjord ecosystem suggest the unique nature of these systems which in turn is influenced by the associated environmental parameters.

Keywords: Bacterial community; Glacier; High-throughput amplicon sequencing; Kongsfjorden; Melt water; Svalbard.

MeSH terms

Arctic Regions
Estuaries
Ice Cover*
Microbiota
Svalbard