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Effects of acute ocean acidification on spatially-diverse polar pelagic foodwebs: insights from on-deck microcosms

Effects of acute ocean acidification on spatially-diverse polar pelagic foodwebs: insights from on-deck microcosms
Effects of acute ocean acidification on spatially-diverse polar pelagic foodwebs: insights from on-deck microcosms

The polar oceans are experiencing some of the largest levels of ocean acidification (OA) resulting from the uptake of anthropogenic carbon dioxide (CO2). Our understanding of the impacts this is having on polar marine communities is mainly derived from studies of single species in laboratory conditions, while the consequences for food web interactions remain largely unknown. This study carried out experimental manipulations of natural pelagic communities at different high latitude sites in both the northern (Nordic Seas) and southern hemispheres (Scotia and Weddell Seas). The aim of this study was to identify more generic responses and greater experimental reproducibility through implementing a series of short term (4 day), multilevel (3 treatment) carbonate chemistry manipulation experiments on unfiltered natural surface ocean communities, including grazing copepods. The experiments were successfully executed at six different sites, covering a diverse range of environmental conditions and differing plankton community compositions. The study identified the interaction between copepods and dinoflagellate cell abundance to be significantly altered by elevated levels of dissolved CO2 (pCO2), with dinoflagellates decreasing relative to ambient conditions across all six experiments. A similar pattern was not observed in any other major phytoplankton group. The patterns indicate that copepods show a stronger preference for dinoflagellates when in elevated pCO2 conditions, demonstrating that changes in food quality and altered grazing selectivity may be a major consequence of ocean acidification. The study also found that transparent exopolymeric particles (TEP) generally increased when pCO2 levels were elevated, but the response was dependent on the exact set of environmental conditions. Bacteria and nannoplankton showed a neutral response to elevated pCO2 and there was no significant relationship between changes in bacterial or nannoplankton abundance and that of TEP concentrations. Overall, the study illustrated that, although some similar responses exist, these contrasting high latitude surface ocean communities are likely to show different responses to the onset of elevated pCO2.
Arctic, Southern Ocean, Copepod, Phytoplankton, Dinoflagellates, Bacteria, Nannoplankton, Transparent exopolymeric particles, PCO2
0967-0645
75-92
Tarling, G.A.
11c6c41e-2840-4c60-b262-b404e58607ee
Peck, V.
b745f5f2-c23a-48e4-8c17-8cfee5086958
Ward, P.
be8f5e51-8144-43cf-8c11-e0c7cf87b86c
Ensor, N.S.
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Achterberg, E.
685ce961-8c45-4503-9f03-50f6561202b9
Tynan, E.
dfed4bbd-ea2a-4ff9-81f5-de2af563943b
Poulton, A.J.
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Mitchell, E.
fc397d48-c2f2-4948-b989-77ebc2d4b256
Zubkov, M.V.
b1dfb3a0-bcff-430c-9031-358a22b50743
Tarling, G.A.
11c6c41e-2840-4c60-b262-b404e58607ee
Peck, V.
b745f5f2-c23a-48e4-8c17-8cfee5086958
Ward, P.
be8f5e51-8144-43cf-8c11-e0c7cf87b86c
Ensor, N.S.
957d02c4-2b8b-4619-9b43-751172fd5aa4
Achterberg, E.
685ce961-8c45-4503-9f03-50f6561202b9
Tynan, E.
dfed4bbd-ea2a-4ff9-81f5-de2af563943b
Poulton, A.J.
14bf64a7-d617-4913-b882-e8495543e717
Mitchell, E.
fc397d48-c2f2-4948-b989-77ebc2d4b256
Zubkov, M.V.
b1dfb3a0-bcff-430c-9031-358a22b50743

Tarling, G.A., Peck, V., Ward, P., Ensor, N.S., Achterberg, E., Tynan, E., Poulton, A.J., Mitchell, E. and Zubkov, M.V. (2016) Effects of acute ocean acidification on spatially-diverse polar pelagic foodwebs: insights from on-deck microcosms. Deep Sea Research Part II: Topical Studies in Oceanography, 127, 75-92. (doi:10.1016/j.dsr2.2016.02.008).

Record type: Article

Abstract


The polar oceans are experiencing some of the largest levels of ocean acidification (OA) resulting from the uptake of anthropogenic carbon dioxide (CO2). Our understanding of the impacts this is having on polar marine communities is mainly derived from studies of single species in laboratory conditions, while the consequences for food web interactions remain largely unknown. This study carried out experimental manipulations of natural pelagic communities at different high latitude sites in both the northern (Nordic Seas) and southern hemispheres (Scotia and Weddell Seas). The aim of this study was to identify more generic responses and greater experimental reproducibility through implementing a series of short term (4 day), multilevel (3 treatment) carbonate chemistry manipulation experiments on unfiltered natural surface ocean communities, including grazing copepods. The experiments were successfully executed at six different sites, covering a diverse range of environmental conditions and differing plankton community compositions. The study identified the interaction between copepods and dinoflagellate cell abundance to be significantly altered by elevated levels of dissolved CO2 (pCO2), with dinoflagellates decreasing relative to ambient conditions across all six experiments. A similar pattern was not observed in any other major phytoplankton group. The patterns indicate that copepods show a stronger preference for dinoflagellates when in elevated pCO2 conditions, demonstrating that changes in food quality and altered grazing selectivity may be a major consequence of ocean acidification. The study also found that transparent exopolymeric particles (TEP) generally increased when pCO2 levels were elevated, but the response was dependent on the exact set of environmental conditions. Bacteria and nannoplankton showed a neutral response to elevated pCO2 and there was no significant relationship between changes in bacterial or nannoplankton abundance and that of TEP concentrations. Overall, the study illustrated that, although some similar responses exist, these contrasting high latitude surface ocean communities are likely to show different responses to the onset of elevated pCO2.

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Accepted/In Press date: 16 February 2016
Published date: May 2016
Keywords: Arctic, Southern Ocean, Copepod, Phytoplankton, Dinoflagellates, Bacteria, Nannoplankton, Transparent exopolymeric particles, PCO2
Organisations: Ocean and Earth Science, Marine Biogeochemistry

Identifiers

Local EPrints ID: 388147
URI: http://eprints.soton.ac.uk/id/eprint/388147
ISSN: 0967-0645
PURE UUID: d70ef6d5-3809-49c6-9adb-4e8f0a612f00

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Date deposited: 19 Feb 2016 10:08
Last modified: 09 Jan 2022 05:23

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Contributors

Author: G.A. Tarling
Author: V. Peck
Author: P. Ward
Author: N.S. Ensor
Author: E. Achterberg
Author: E. Tynan
Author: A.J. Poulton
Author: E. Mitchell
Author: M.V. Zubkov

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