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| Titel |
Differential methane oxidation activity and microbial community composition at cold seeps in the Arctic off western Svalbard |
| VerfasserIn |
Friederike Gründger, Mette M. Svenning, Helge Niemann, Anna Silyakova, Pavel Serov, Wei Li Hong, Gunter Wegener, Giuliana Panieri, JoLynn Carroll |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250134911
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| Publikation (Nr.) |
 EGU/EGU2016-15688.pdf |
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| Zusammenfassung |
| Most models considering climate change related bottom water warming suggest that gas
hydrates may become destabilized, leading to the mobilization of methane into seabed and
water column ecosystems, and, eventually, into the atmosphere. However, the capacity of
methanotrophic microbes retaining methane in sediments and the hydrosphere is not well
constrained. Here, we investigate the microbial utilization of methane in sediments and the
water column, focusing on cold seeps discovered at the arctic continental margin of western
Svalbard. We measured ex situ rates of methane oxidation and sulfate reduction in two active
gas flare sites with different geological settings at the Vestnesa Ridge (1204 m water depth)
and within a pingolike feature area southwest off Svalbard (PLF; 380 m water
depth).
Our results show contrarily situations at our two sampling sites: At Vestnesa Ridge we
find high methane oxidation rates with values up to 2055 nmol cm−3 d−1 at the
sediment surface where the sediments are oversaturated with methane. Whereas,
methane concentration and oxidation rates are low in the overlying water column
(2 pmol cm−3 d−1). In contrast, at the sediment surface at PLF methane concentration and
oxidation rates are considerably lower (up to 1.8 nmol cm−3 d−1). While the overlying
bottom water contains high concentration of methane and shows oxidation rates with values
of up to 3.8 nmol cm−3 d−1. The data on methane oxidation and sulfate reduction activity
are compared to the sediment geochemistry and to data from metagenomic analysis
identifying the methanotrophic community composition. These results provide unique insight
into the dynamic responses of the seabed biological filter at cold seeps in the Arctic off
western Svalbard.
This study is part of the Centre for Arctic Gas Hydrate, Environment and Climate and was
supported by the Research Council of Norway through its Centres of Excellence funding
scheme grant No. 223259. |
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