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dc.contributor.authorSauer, Simone
dc.contributor.authorHong, Wei-Li
dc.contributor.authorKnies, Jochen
dc.contributor.authorLepland, Aivo
dc.contributor.authorForwick, Matthias
dc.contributor.authorKlug, Martin
dc.contributor.authorEichinger, Florian
dc.contributor.authorBaranwal, Soma
dc.contributor.authorCremiere, Antoine
dc.contributor.authorChand, Shyam
dc.contributor.authorSchubert, Carsten J.
dc.date.accessioned2017-03-31T07:47:53Z
dc.date.available2017-03-31T07:47:53Z
dc.date.issued2016-10-22
dc.description.abstractTo better understand the present and past carbon cycling and transformation processes in methane-influenced fjord and shelf areas of northern Norway, we compared two sediment cores from the Hola trough and from Ullsfjorden. We investigated (1) the organic matter composition and sedimentological characteristics to study the sources of organic carbon (C<sub>org</sub>) and the factors influencing C<sub>org</sub> burial, (2) pore water geochemistry to determine the contribution of organoclastic sulfate reduction and methanogenesis to total organic carbon turnover, and (3) the carbon isotopic signature of hydrocarbons to identify the carbon transformation processes and gas sources. High sedimentation and C<sub>org</sub> accumulation rates in Ullsfjorden support the notion that fjords are important C<sub>org</sub> sinks. The depth of the sulfate-methanetransition (SMT) in the fjord is controlled by the supply of predominantly marine organic matter to the sediment. Organoclastic sulfate reduction accounts for 60% of the total depth-integrated sulfate reduction in the fjord. In spite of the presence of ethane, propane, and butane, we suggest a purely microbial origin of light hydrocarbons in the sediments based on their low δ<sup>13</sup>C values. In the Hola trough, sedimentation and C<sub>org</sub> accumulation rates changed during the deglacial-to-post-glacial transition from approximately 80 cm ka<sup>-1</sup> to erosion at present. Thus, C<sub>org</sub> burial in this part of the shelf is presently absent. Low organic matter content in the sediment and low rates of organoclastic sulfate reduction (only 3% of total depth-integrated sulfate reduction) entail that the shallow depth of the SMT is controlled mostly by ascending thermogenic methane from deeper sources.en_US
dc.descriptionSource at <a href=http://doi.org/10.1002/2016GC006296>http://doi.org/10.1002/2016GC006296</a>en
dc.descriptionA manuscript version of this article was part of Simone Sauer's doctoral thesis, which is available in Munin at <a href=http://hdl.handle.net/10037/9548>http://hdl.handle.net/10037/9548</a>en
dc.identifier.citationSauer, S. et.al.: Sources and turnover of organic carbon and methane in fjord and shelf sediments off Northern Norway. Geochemistry Geophysics Geosystems, 2016;17(10):4011-4031en_US
dc.identifier.cristinIDFRIDAID 1392123
dc.identifier.doi10.1002/2016GC006296
dc.identifier.issn1525-2027
dc.identifier.urihttps://hdl.handle.net/10037/10912
dc.language.isoengen_US
dc.publisherAmerican Geophysical Union (AGU)en_US
dc.relation.journalGeochemistry Geophysics Geosystems
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/PETROMAKS2/255150/Norway/Norwegian margin fluid systems and methane- derived carbonate crusts - Recent scientific advances in service of petroleum exploration//en_US
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/en_US
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466en_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466en_US
dc.titleSources and turnover of organic carbon and methane in fjord and shelf sediments off Northern Norwayen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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