The University of Southampton
University of Southampton Institutional Repository

Summer microbial community composition governed by upper-ocean stratification and nutrient availability in northern Marguerite Bay, Antarctica

Summer microbial community composition governed by upper-ocean stratification and nutrient availability in northern Marguerite Bay, Antarctica
Summer microbial community composition governed by upper-ocean stratification and nutrient availability in northern Marguerite Bay, Antarctica
The Western Antarctic Peninsula warmed significantly during the second half of the twentieth century, with a concurrent retreat of the majority of its glaciers, and marked changes in the sea-ice field. These changes may affect summertime upper-ocean stratification, and thereby the seasonal dynamics of phytoplankton and bacteria. In the present study, we examined coastal Antarctic microbial community dynamics by pigment analysis and applying molecular tools, and analysed various environmental parameters to identify the most important environmental drivers. Sampling focussed on the austral summer of 2009–2010 at the Rothera oceanographic and biological Time Series (RaTS) site in northern Marguerite bay, Antarctica. The Antarctic summer was characterized by a salinity decrease (measured at 15 m depth) coinciding with increased meteoric water fraction. Maximum Chl-a values of 35 µg l-1 were observed during midsummer and mainly comprised of diatoms. Microbial community fingerprinting revealed four distinct periods in phytoplankton succession during the summer while bacteria showed a delayed response to the phytoplankton community. Non-metric multidimensional scaling analyses showed that phytoplankton community dynamics were mainly directed by temperature, mixed layer depth and wind speed. Both high and low N/P ratios might have influenced phytoplankton biomass accumulation. The bacterioplankton community composition was mainly governed by Chl-a, suggesting a link to phytoplankton community changes. High-throughput 16 S and 18 S rRNA amplicon sequencing revealed stable eukaryotic and bacterial communities with regards to observed species, yet varying temporal relative contributions. Eukaryotic sequences were dominated by pennate diatoms in December followed by polar centric diatoms in January and February. Our results imply that the reduction of mixed layer depth during summer, caused by meltwater-related surface stratification, promotes a succession in diatoms rather than in nanophytoflagellates in northern Marguerite Bay, which may favour higher trophic levels.
Phytoplankton, Bacteria, Diatoms, macronutrients, MiSeq sequencing, glacial melt
0967-0645
151–166
Rozema, Patrick D.
93d5f78f-ba64-49b0-b420-e8ed956f9d2f
Biggs, Tristan
e50d2770-1b56-4387-9b8f-084e0cd05824
Sprong, Pim A.A.
2b635dc5-6b37-4a6d-be64-050b9ce72085
Buma, Anita G.J.
a9d28b33-293f-4c15-9a26-00acf20bcb1c
Venables, Hugh J.
076cfe85-e2f9-4e69-8793-0ab225e7fadd
Evans, Claire
93350709-cad3-4adf-8483-9bee595412f4
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd
Bolhuis, Henk
e830e260-839d-4a03-8ae2-b3f19f1da8d5
Rozema, Patrick D.
93d5f78f-ba64-49b0-b420-e8ed956f9d2f
Biggs, Tristan
e50d2770-1b56-4387-9b8f-084e0cd05824
Sprong, Pim A.A.
2b635dc5-6b37-4a6d-be64-050b9ce72085
Buma, Anita G.J.
a9d28b33-293f-4c15-9a26-00acf20bcb1c
Venables, Hugh J.
076cfe85-e2f9-4e69-8793-0ab225e7fadd
Evans, Claire
93350709-cad3-4adf-8483-9bee595412f4
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd
Bolhuis, Henk
e830e260-839d-4a03-8ae2-b3f19f1da8d5

Rozema, Patrick D., Biggs, Tristan, Sprong, Pim A.A., Buma, Anita G.J., Venables, Hugh J., Evans, Claire, Meredith, Michael P. and Bolhuis, Henk (2017) Summer microbial community composition governed by upper-ocean stratification and nutrient availability in northern Marguerite Bay, Antarctica. Deep Sea Research Part II: Topical Studies in Oceanography, 139, 151–166. (doi:10.1016/j.dsr2.2016.11.016).

Record type: Article

Abstract

The Western Antarctic Peninsula warmed significantly during the second half of the twentieth century, with a concurrent retreat of the majority of its glaciers, and marked changes in the sea-ice field. These changes may affect summertime upper-ocean stratification, and thereby the seasonal dynamics of phytoplankton and bacteria. In the present study, we examined coastal Antarctic microbial community dynamics by pigment analysis and applying molecular tools, and analysed various environmental parameters to identify the most important environmental drivers. Sampling focussed on the austral summer of 2009–2010 at the Rothera oceanographic and biological Time Series (RaTS) site in northern Marguerite bay, Antarctica. The Antarctic summer was characterized by a salinity decrease (measured at 15 m depth) coinciding with increased meteoric water fraction. Maximum Chl-a values of 35 µg l-1 were observed during midsummer and mainly comprised of diatoms. Microbial community fingerprinting revealed four distinct periods in phytoplankton succession during the summer while bacteria showed a delayed response to the phytoplankton community. Non-metric multidimensional scaling analyses showed that phytoplankton community dynamics were mainly directed by temperature, mixed layer depth and wind speed. Both high and low N/P ratios might have influenced phytoplankton biomass accumulation. The bacterioplankton community composition was mainly governed by Chl-a, suggesting a link to phytoplankton community changes. High-throughput 16 S and 18 S rRNA amplicon sequencing revealed stable eukaryotic and bacterial communities with regards to observed species, yet varying temporal relative contributions. Eukaryotic sequences were dominated by pennate diatoms in December followed by polar centric diatoms in January and February. Our results imply that the reduction of mixed layer depth during summer, caused by meltwater-related surface stratification, promotes a succession in diatoms rather than in nanophytoflagellates in northern Marguerite Bay, which may favour higher trophic levels.

Text
1-s2.0-S0967064516303782-main.pdf - Accepted Manuscript
Download (1MB)

More information

Accepted/In Press date: 26 November 2016
Published date: 1 May 2017
Keywords: Phytoplankton, Bacteria, Diatoms, macronutrients, MiSeq sequencing, glacial melt
Organisations: Ocean Biochemistry & Ecosystems, National Oceanography Centre

Identifiers

Local EPrints ID: 403427
URI: http://eprints.soton.ac.uk/id/eprint/403427
ISSN: 0967-0645
PURE UUID: 7d0c0ad8-6dcb-4dc8-857e-6309463ade7a

Catalogue record

Date deposited: 30 Nov 2016 09:58
Last modified: 15 Mar 2024 06:06

Export record

Altmetrics

Contributors

Author: Patrick D. Rozema
Author: Tristan Biggs
Author: Pim A.A. Sprong
Author: Anita G.J. Buma
Author: Hugh J. Venables
Author: Claire Evans
Author: Michael P. Meredith
Author: Henk Bolhuis

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×