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dc.contributor.authorYao, Haoyi
dc.contributor.authorHong, Wei-Li
dc.contributor.authorPanieri, Giuliana
dc.contributor.authorSauer, Simone
dc.contributor.authorTorres, Marta E.
dc.contributor.authorLehmann, Moritz F.
dc.contributor.authorGründger, Friederike
dc.contributor.authorNiemann, Helge
dc.date.accessioned2019-08-05T10:46:50Z
dc.date.available2019-08-05T10:46:50Z
dc.date.issued2019-05-29
dc.description.abstractWe report a rare observation of a mini-fracture in near-surface sediments (30 cm below the seafloor) visualized using a rotational scanning X-ray of a core recovered from the Lomvi pockmark, Vestnesa Ridge, west of Svalbard (1200 m water depth). Porewater geochemistry and lipid biomarker signatures revealed clear differences in the geochemical and biogeochemical regimes of this core compared with two additional unfractured cores recovered from pockmark sites at Vestnesa Ridge, which we attribute to differential methane transport mechanisms. <br>In the sediment core featuring the shallow mini-fracture at pockmark Lomvi, we observed high concentrations of both methane and sulfate throughout the core in tandem with moderately elevated values for total alkalinity, 13C-depleted dissolved inorganic carbon (DIC), and 13C-depleted lipid biomarkers (diagnostic for the slow-growing microbial communities mediating the anaerobic oxidation of methane with sulfate – AOM).<br> In a separate unfractured core, recovered from the same pockmark about 80 m away from the fractured core, we observed complete sulfate depletion in the top centimeters of the sediment and much more pronounced signatures of AOM than in the fractured core. Our data indicate a gas advection-dominated transport mode in both cores, facilitating methane migration into sulfate-rich surface sediments. <br>However, the moderate expression of AOM signals suggest a rather recent onset of gas migration at the site of the fractured core, while the geochemical evidence for a well-established AOM community at the second coring site suggest that gas migration has been going on for a longer period of time. <br>A third core recovered from another pockmark along the Vestnesa Ridge Lunde pockmark was dominated by diffusive transport with only weak geochemical and biogeochemical evidence for AOM. Our study highlights that advective fluid and gas transport supported by mini-fractures can be important in modulating methane dynamics in surface sediments.en_US
dc.description.sponsorshipThis work was supported by the Research Council of Norway through its Centres of Excellence funding scheme (project number 223259). <br>The publication charges for this article have been funded by a grant from the publication fund of UiT The Arctic University of Norway in Tromsø.en_US
dc.identifier.citationYao, H., Hong, H., Panieri, G., Sauer, S., Torres, M.E., Lehmann, M.F., Gründger, F., Niemann, H.(2019) Fracture-controlled fluid transport supports microbial methane-oxidizing communities at Vestnesa Ridge. <i>Biogeosciences,16</i> (10), 2221-2232. http://dx.doi.org/10.5194/bg-16-2221-2019en_US
dc.identifier.cristinIDFRIDAID 1701329
dc.identifier.doihttps://doi.org/10.5194/bg-16-2221-2019
dc.identifier.issn1726-4170
dc.identifier.issn1726-4189
dc.identifier.urihttps://hdl.handle.net/10037/15839
dc.language.isoengen_US
dc.publisherEuropean Geosciences Union (EGU)en_US
dc.relation.ispartofYao, H. (2020). Reconstruction of past and present methane emission in the Arctic cold seeps using biogeochemical proxies. (Doctoral thesis). <a href=https://hdl.handle.net/10037/17821>https://hdl.handle.net/10037/17821. </a>
dc.relation.journalBiogeosciences
dc.relation.projectIDNorges forskningsråd: 223259en_US
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Technology: 500::Rock and petroleum disciplines: 510::Geological engineering: 513en_US
dc.subjectVDP::Teknologi: 500::Berg‑ og petroleumsfag: 510::Geoteknikk: 513en_US
dc.titleFracture-controlled fluid transport supports microbial methane-oxidizing communities at Vestnesa Ridgeen_US
dc.typeJournal articleen_US
dc.typePeer revieweden_US


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