Effects of Vertical Water Mass Segregation on Bacterial Community Structure in the Beaufort Sea.

Andrew S. Lang,Yunyun Fu,Richard B. Rivkin

doi:10.3390/microorganisms7100385

Andrew S. Lang, Yunyun Fu + Show 1 more

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https://doi.org/10.3390/microorganisms7100385

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Journal: Microorganisms	Publication Date: Sep 24, 2019
Citations: 4	License type: CC BY 4.0

Affiliation: Memorial University of Newfoundland

Abstract

The Arctic Ocean is one of the least well-studied marine microbial ecosystems. Its low-temperature and low-salinity conditions are expected to result in distinct bacterial communities, in comparison to lower latitude oceans. However, this is an ocean currently in flux, with climate change exerting pronounced effects on sea-ice coverage and freshwater inputs. How such changes will affect this ecosystem are poorly constrained. In this study, we characterized the bacterial community compositions at different depths in both coastal, freshwater-influenced, and pelagic, sea-ice-covered locations in the Beaufort Sea in the western Canadian Arctic Ocean. The environmental factors controlling the bacterial community composition and diversity were investigated. Alphaproteobacteria dominated the bacterial communities in samples from all depths and stations. The Pelagibacterales and Rhodobacterales groups were the predominant taxonomic representatives within the Alphaproteobacteria. Bacterial communities in coastal and offshore samples differed significantly, and vertical water mass segregation was the controlling factor of community composition among the offshore samples, regardless of the taxonomic level considered. These data provide an important baseline view of the bacterial community in this ocean system that will be of value for future studies investigating possible changes in the Arctic Ocean in response to global change and/or anthropogenic disturbance.

Highlights

Bacterioplankton are the most abundant organisms in the sea, where they exist in complex and diverse communities
Water mass was described as the driving factor for bacterial communities across various basins in the deep Arctic and North Atlantic Oceans [17,76], and our findings show it plays a critical role in the upper Arctic Ocean
We have found that the Arctic Ocean bacterial community is mostly controlled by the vertical water mass segregation

Summary

Introduction

Bacterioplankton are the most abundant organisms in the sea, where they exist in complex and diverse communities. The widespread and abundant groups include members of the alphaproteobacterial orders Pelagibacterales (i.e., SAR11) [6,22,23,24,25] and Rhodobacterales (i.e., roseobacters) [26,27,28,29,30]. These two lineages are found primarily in the upper ocean and appear to use distinct strategies for their success in marine environments. Previous studies have documented they are found in high abundance in the Arctic Ocean [39,40,41,42]

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