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dc.contributor.authorNewman, Kori R.  Concept link
dc.contributor.authorCormier, Marie-Helene  Concept link
dc.contributor.authorWeissel, Jeffrey K.  Concept link
dc.contributor.authorDriscoll, Neal W.  Concept link
dc.contributor.authorKastner, Miriam  Concept link
dc.contributor.authorSolomon, Evan A.  Concept link
dc.contributor.authorRobertson, Gretchen  Concept link
dc.contributor.authorHill, Jenna C.  Concept link
dc.contributor.authorSingh, Hanumant  Concept link
dc.contributor.authorCamilli, Richard  Concept link
dc.contributor.authorEustice, Ryan M.  Concept link
dc.date.accessioned2008-05-16T19:59:35Z
dc.date.available2008-05-16T19:59:35Z
dc.date.issued2007-11
dc.identifier.urihttps://hdl.handle.net/1912/2234
dc.descriptionAuthor Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 267 (2008): 341-352, doi:10.1016/j.epsl.2007.11.053.en
dc.description.abstractDetailed near-bottom investigation of a series of giant, kilometer scale, elongate pockmarks along the edge of the mid-Atlantic continental shelf confirms that methane is actively venting at the site. Dissolved methane concentrations, which were measured with a commercially available methane sensor (METS) designed by Franatech GmbH mounted on an autonomous underwater vehicle (AUV), are as high as 100 nM. These values are well above expected background levels (1-4 nM) for the open ocean. Sediment pore water geochemistry gives further evidence of methane advection through the seafloor. Isotopically light carbon in the dissolved methane samples indicates a primarily biogenic source. The spatial distribution of the near-bottom methane anomalies (concentrations above open ocean background), combined with water column salinity and temperature vertical profiles, indicate that methane-rich water is not present across the entire width of the pockmarks, but is laterally restricted to their edges. We suggest that venting is primarily along the top of the pockmark walls with some advection and dispersion due to local currents. The highest methane concentrations observed with the METS sensor occur at a small, circular pockmark at the southern end of the study area. This observation is compatible with a scenario where the larger, elongate pockmarks evolve through coalescing smaller pockmarks.en
dc.description.sponsorshipThis work was supported by NSF grants OCE- 0242426, OCE-0242804 and OCDE-0242449 and ONR grant N00014-02-1-0691.en
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen
dc.relation.urihttps://doi.org/10.1016/j.epsl.2007.11.053
dc.subjectPockmarksen
dc.subjectSeafloor ventingen
dc.subjectMethaneen
dc.subjectAUVen
dc.titleActive methane venting observed at giant pockmarks along the U.S. mid-Atlantic shelf breaken
dc.typePreprinten


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