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Silica cycling and isotopic composition in northern Marguerite Bay on the rapidly-warming western Antarctic Peninsula

Silica cycling and isotopic composition in northern Marguerite Bay on the rapidly-warming western Antarctic Peninsula
Silica cycling and isotopic composition in northern Marguerite Bay on the rapidly-warming western Antarctic Peninsula

The Southern Ocean is a key region for silica (Si) cycling, and the isotopic signatures established here influence the rest of the world's oceans. The climate and ecosystem of the Southern Ocean are changing rapidly, with the potential to impact Si cycling and isotope dynamics. This study examines high-resolution time-series dataset of dissolved Si concentrations and isotopic signatures, particulate Si concentrations and diatom speciation at a coastal site on the western Antarctic Peninsula (WAP), in order to characterise changes in Si cycling with respect to changes occurring in productivity and diatom assemblages. Dissolved and particulate Si phases reflect the dominant control of biological uptake, and combined with isotopic fractionation were consistent with a season of low/intermediate productivity. Biogenic Si is tightly coupled to both chlorophyll and particulate organic carbon at the sampling site, consistent with diatom-dominated phytoplankton assemblages along the WAP. Variability in diatom speciation has a negligible impact on the isotopic signature of dissolved Si in surface waters, although this is unlikely to hold for sediments due to differential dissolution of diatom species. A continued decline in diatom productivity along the WAP would likely result in an increasing unused Si inventory, which can potentially feed back into Si-limited areas, promoting diatom growth and carbon drawdown further afield.

Diatoms, Fractionation, Ryder Bay, Silica, Silicon isotopes
0967-0645
132-142
Annett, Amber L.
de404d72-7e90-4dbd-884a-1df813808276
Henley, Sian F.
cd7c7f77-8494-46ad-98a9-08907fa6e06b
Venables, Hugh J.
ed72170e-cf1b-4b38-b5e8-d3eed65cdb06
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd
Clarke, Andrew
b54fba97-b95a-4a17-86d6-c2bb0f1d10e3
Ganeshram, Raja S.
108fdc69-5502-4b6f-922f-dd12b398e267
Annett, Amber L.
de404d72-7e90-4dbd-884a-1df813808276
Henley, Sian F.
cd7c7f77-8494-46ad-98a9-08907fa6e06b
Venables, Hugh J.
ed72170e-cf1b-4b38-b5e8-d3eed65cdb06
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd
Clarke, Andrew
b54fba97-b95a-4a17-86d6-c2bb0f1d10e3
Ganeshram, Raja S.
108fdc69-5502-4b6f-922f-dd12b398e267

Annett, Amber L., Henley, Sian F., Venables, Hugh J., Meredith, Michael P., Clarke, Andrew and Ganeshram, Raja S. (2017) Silica cycling and isotopic composition in northern Marguerite Bay on the rapidly-warming western Antarctic Peninsula. Deep Sea Research Part II: Topical Studies in Oceanography, 139, 132-142. (doi:10.1016/j.dsr2.2016.09.006).

Record type: Article

Abstract

The Southern Ocean is a key region for silica (Si) cycling, and the isotopic signatures established here influence the rest of the world's oceans. The climate and ecosystem of the Southern Ocean are changing rapidly, with the potential to impact Si cycling and isotope dynamics. This study examines high-resolution time-series dataset of dissolved Si concentrations and isotopic signatures, particulate Si concentrations and diatom speciation at a coastal site on the western Antarctic Peninsula (WAP), in order to characterise changes in Si cycling with respect to changes occurring in productivity and diatom assemblages. Dissolved and particulate Si phases reflect the dominant control of biological uptake, and combined with isotopic fractionation were consistent with a season of low/intermediate productivity. Biogenic Si is tightly coupled to both chlorophyll and particulate organic carbon at the sampling site, consistent with diatom-dominated phytoplankton assemblages along the WAP. Variability in diatom speciation has a negligible impact on the isotopic signature of dissolved Si in surface waters, although this is unlikely to hold for sediments due to differential dissolution of diatom species. A continued decline in diatom productivity along the WAP would likely result in an increasing unused Si inventory, which can potentially feed back into Si-limited areas, promoting diatom growth and carbon drawdown further afield.

Full text not available from this repository.

More information

e-pub ahead of print date: 1 October 2016
Published date: 1 May 2017
Keywords: Diatoms, Fractionation, Ryder Bay, Silica, Silicon isotopes

Identifiers

Local EPrints ID: 418526
URI: https://eprints.soton.ac.uk/id/eprint/418526
ISSN: 0967-0645
PURE UUID: 6407216a-9348-4104-99f0-6e72d5e0edd7
ORCID for Amber L. Annett: ORCID iD orcid.org/0000-0002-3730-2438

Catalogue record

Date deposited: 09 Mar 2018 17:31
Last modified: 15 Aug 2019 00:26

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