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Methane-carbon flow into the benthic food web at cold seeps – a case study from the Costa Rica subduction zone

Niemann, Helge and Linke, Peter and Knittel, Katrin and MacPherson, Enrique and Boetius, Antje and Brückmann, Warner and Larvik, Gaute and Wallmann, Klaus and Schacht, Ulrike and Omoregie, Enoma and Hilton, David and Brown, Kevin and Rehder, Gregor. (2013) Methane-carbon flow into the benthic food web at cold seeps – a case study from the Costa Rica subduction zone. PLoS ONE, Vol. 8, H. 10 , e74894.

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Abstract

Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp.) feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15∶0 and C17∶1ω6c with stable carbon isotope compositions as low as −53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other 13C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Ehemalige Einheiten Umweltwissenschaften
05 Faculty of Science > Departement Umweltwissenschaften > Umweltgeowissenschaften > Geochemie Stoffkreisläufe (Lehmann)
UniBasel Contributors:Niemann, Helge
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Public Library of Science
e-ISSN:1932-6203
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:31 Aug 2018 06:39
Deposited On:31 Jan 2014 09:49

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