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| Titel |
Efficiency and adaptability of the benthic methane filter at Quepos Slide cold seeps, offshore of Costa Rica |
| VerfasserIn |
P. Steeb, S. Krause, P. Linke, C. Hensen, A. W. Dale, M. Nuzzo, T. Treude |
| 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 ; 12, no. 22 ; Nr. 12, no. 22 (2015-11-25), S.6687-6706 |
| Datensatznummer |
250118175
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| Publikation (Nr.) |
 copernicus.org/bg-12-6687-2015.pdf |
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| Zusammenfassung |
Large amounts of methane are delivered by fluids through the erosive forearc
of the convergent margin offshore of Costa Rica and lead to the formation of
cold seeps at the sediment surface. Besides mud extrusion, numerous cold
seeps are created by landslides induced by seamount subduction or fluid
migration along major faults. Most of the dissolved methane migrating through
the sediments of cold seeps is oxidized within the benthic microbial methane
filter by anaerobic oxidation of methane (AOM). Measurements of AOM and
sulfate reduction as well as numerical modeling of porewater profiles
revealed a highly active and efficient benthic methane filter at the Quepos Slide
site, a landslide on the continental slope between the Nicoya and Osa
Peninsula. Integrated areal rates of AOM ranged from 12.9 ± 6.0 to
45.2 ± 11.5 mmol m−2 d−1, with only 1 to 2.5 % of
the upward methane flux being released into the water column.
Additionally, two parallel sediment cores from Quepos Slide were used for in
vitro experiments in a recently developed
sediment-flow-through (SLOT) system to simulate an
increased fluid and methane flux from the bottom of the sediment core. The
benthic methane filter revealed a high adaptability whereby the methane
oxidation efficiency responded to the increased fluid flow within ca. 170 d.
To our knowledge, this study provides the first estimation of the natural
biogeochemical response of seep sediments to changes in fluid flow. |
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