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Detoxification of sulphidic African shelf waters by blooming chemolithotrophs

Detoxification of sulphidic African shelf waters by blooming chemolithotrophs
Detoxification of sulphidic African shelf waters by blooming chemolithotrophs
Coastal waters support approximately 90 per cent of global fisheries and are therefore an important food reserve for our planet. Eutrophication of these waters, due to human activity, leads to severe oxygen depletion and the episodic occurrence of hydrogen sulphide-toxic to multi-cellular life-with disastrous consequences for coastal ecosytems. Here we show that an area of approximately 7,000 km(2) of African shelf, covered by sulphidic water, was detoxified by blooming bacteria that oxidized the biologically harmful sulphide to environmentally harmless colloidal sulphur and sulphate. Combined chemical analyses, stoichiometric modelling, isotopic incubations, comparative 16S ribosomal RNA, functional gene sequence analyses and fluorescence in situ hybridization indicate that the detoxification proceeded by chemolithotrophic oxidation of sulphide with nitrate and was mainly catalysed by two discrete populations of gamma- and epsilon-proteobacteria. Chemolithotrophic bacteria, accounting for approximately 20 per cent of the bacterioplankton in sulphidic waters, created a buffer zone between the toxic sulphidic subsurface waters and the oxic surface waters, where fish and other nekton live. This is the first time that large-scale detoxification of sulphidic waters by chemolithotrophs has been observed in an open-ocean system. The data suggest that sulphide can be completely consumed by bacteria in the subsurface waters and, thus, can be overlooked by remote sensing or monitoring of shallow coastal waters. Consequently, sulphidic bottom waters on continental shelves may be more common than previously believed, and could therefore have an important but as yet neglected effect on benthic communities.
0028-0836
581-584
Lavik, Gaute
29014780-d97c-41c0-8b59-a230bdfcdb37
Stührmann, Torben
bd695c79-66fd-4cbf-abb9-ee87d93802f9
Brüchert, Volker
a36a8f48-866b-455e-b27e-7a1983dba107
Van der Plas, Anja
8261378d-cd3b-4bda-b9af-f9099894ec6c
Mohrholz, Volker
25a7de89-0f75-499b-b1d1-a9834ba2b7a7
Lam, Phyllis
996aef80-a15d-4827-aed8-1b97b378f6ad
Mußmann, Marc
2ba0bbaa-a0f2-4b60-aa41-94d13db4e0cb
Fuchs, Bernhard M.
dfa49acc-93b0-4d04-87af-52ec11fa6b0e
Amann, Rudolf
315b5cfc-deaa-4283-baf4-7fb655fe5730
Lass, Ulrich
c1b3164f-3cf3-45a2-bd4e-13f783c439c2
Kuypers, Marcel M.M.
b6288cfb-42bc-469c-93fe-8fbb40d97bec
Lavik, Gaute
29014780-d97c-41c0-8b59-a230bdfcdb37
Stührmann, Torben
bd695c79-66fd-4cbf-abb9-ee87d93802f9
Brüchert, Volker
a36a8f48-866b-455e-b27e-7a1983dba107
Van der Plas, Anja
8261378d-cd3b-4bda-b9af-f9099894ec6c
Mohrholz, Volker
25a7de89-0f75-499b-b1d1-a9834ba2b7a7
Lam, Phyllis
996aef80-a15d-4827-aed8-1b97b378f6ad
Mußmann, Marc
2ba0bbaa-a0f2-4b60-aa41-94d13db4e0cb
Fuchs, Bernhard M.
dfa49acc-93b0-4d04-87af-52ec11fa6b0e
Amann, Rudolf
315b5cfc-deaa-4283-baf4-7fb655fe5730
Lass, Ulrich
c1b3164f-3cf3-45a2-bd4e-13f783c439c2
Kuypers, Marcel M.M.
b6288cfb-42bc-469c-93fe-8fbb40d97bec

Lavik, Gaute, Stührmann, Torben, Brüchert, Volker, Van der Plas, Anja, Mohrholz, Volker, Lam, Phyllis, Mußmann, Marc, Fuchs, Bernhard M., Amann, Rudolf, Lass, Ulrich and Kuypers, Marcel M.M. (2009) Detoxification of sulphidic African shelf waters by blooming chemolithotrophs. Nature, 457 (7229), 581-584. (doi:10.1038/nature07588). (PMID:19078958)

Record type: Article

Abstract

Coastal waters support approximately 90 per cent of global fisheries and are therefore an important food reserve for our planet. Eutrophication of these waters, due to human activity, leads to severe oxygen depletion and the episodic occurrence of hydrogen sulphide-toxic to multi-cellular life-with disastrous consequences for coastal ecosytems. Here we show that an area of approximately 7,000 km(2) of African shelf, covered by sulphidic water, was detoxified by blooming bacteria that oxidized the biologically harmful sulphide to environmentally harmless colloidal sulphur and sulphate. Combined chemical analyses, stoichiometric modelling, isotopic incubations, comparative 16S ribosomal RNA, functional gene sequence analyses and fluorescence in situ hybridization indicate that the detoxification proceeded by chemolithotrophic oxidation of sulphide with nitrate and was mainly catalysed by two discrete populations of gamma- and epsilon-proteobacteria. Chemolithotrophic bacteria, accounting for approximately 20 per cent of the bacterioplankton in sulphidic waters, created a buffer zone between the toxic sulphidic subsurface waters and the oxic surface waters, where fish and other nekton live. This is the first time that large-scale detoxification of sulphidic waters by chemolithotrophs has been observed in an open-ocean system. The data suggest that sulphide can be completely consumed by bacteria in the subsurface waters and, thus, can be overlooked by remote sensing or monitoring of shallow coastal waters. Consequently, sulphidic bottom waters on continental shelves may be more common than previously believed, and could therefore have an important but as yet neglected effect on benthic communities.

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More information

e-pub ahead of print date: 10 December 2008
Published date: 29 January 2009
Organisations: Ocean Biochemistry & Ecosystems

Identifiers

Local EPrints ID: 349918
URI: http://eprints.soton.ac.uk/id/eprint/349918
ISSN: 0028-0836
PURE UUID: afd50b7b-8579-4bf8-a5a3-9f2253aafe52
ORCID for Phyllis Lam: ORCID iD orcid.org/0000-0003-2067-171X

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Date deposited: 13 Mar 2013 14:02
Last modified: 15 Mar 2024 03:47

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Contributors

Author: Gaute Lavik
Author: Torben Stührmann
Author: Volker Brüchert
Author: Anja Van der Plas
Author: Volker Mohrholz
Author: Phyllis Lam ORCID iD
Author: Marc Mußmann
Author: Bernhard M. Fuchs
Author: Rudolf Amann
Author: Ulrich Lass
Author: Marcel M.M. Kuypers

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