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| Titel |
Comparative studies of pelagic microbial methane oxidation within the redox zones of the Gotland Deep and Landsort Deep (central Baltic Sea) |
| VerfasserIn |
G. Jakobs, G. Rehder, G. Jost, K. Kießlich, M. Labrenz, O. Schmale |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 12 ; Nr. 10, no. 12 (2013-12-03), S.7863-7875 |
| Datensatznummer |
250085453
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| Publikation (Nr.) |
 copernicus.org/bg-10-7863-2013.pdf |
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| Zusammenfassung |
| Pelagic methane oxidation was investigated in dependence on differing
hydrographic conditions within the redox zone of the Gotland Deep (GD) and
Landsort Deep (LD), central Baltic Sea. The redox zone of both deeps, which
indicates the transition between oxic and anoxic conditions, was
characterized by a pronounced methane concentration gradient between the deep
water (GD: 1233 nM, 223 m; LD: 2935 nM, 422 m) and the surface water (GD
and LD < 10 nM). This gradient together with a 13C CH4
enrichment (δ13C CH4 deep water: GD −84‰, LD
−71‰; redox zone: GD −60‰, LD −20‰;
surface water: GD −47‰, LD −50‰; δ13C
CH4 vs. Vienna Pee Dee Belemnite standard), clearly indicating microbial
methane consumption within the redox zone. Expression analysis of the methane
monooxygenase identified one active type I methanotrophic bacterium in
both redox zones. In contrast, the turnover of methane within the redox zones
showed strong differences between the two basins (GD: max. 0.12 nM d−1, LD: max. 0.61 nM d−1), with a nearly four-times-lower turnover
time of methane in the LD (GD: 455 d, LD: 127 d). Vertical mixing rates for
both deeps were calculated on the base of the methane concentration profile
and the consumption of methane in the redox zone (GD:
2.5 × 10–6 m2 s−1, LD:
1.6 × 10–5 m2 s−1). Our study identified vertical
transport of methane from the deep-water body towards the redox zone as well
as differing hydrographic conditions (lateral intrusions and vertical mixing)
within the redox zone of these deeps as major factors that determine the
pelagic methane oxidation. |
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