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dc.contributor.authorLi, Qian P.  Concept link
dc.contributor.authorHansell, Dennis A.  Concept link
dc.contributor.authorMcGillicuddy, Dennis J.  Concept link
dc.contributor.authorBates, Nicholas R.  Concept link
dc.contributor.authorJohnson, Rodney J.  Concept link
dc.date.accessioned2010-06-09T19:49:08Z
dc.date.available2010-06-09T19:49:08Z
dc.date.issued2008-10-11
dc.identifier.citationJournal of Geophysical Research 113 (2008): C10006en_US
dc.identifier.urihttps://hdl.handle.net/1912/3626
dc.descriptionAuthor Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): C10006, doi:10.1029/2008JC004840.en_US
dc.description.abstractMechanisms of nutrient supply in oligotrophic ocean systems remain inadequately understood and quantified. In the North Atlantic Subtropical Gyre, for example, the observed rates of new production are apparently not balanced by nutrient supply via vertical mixing. Mesoscale eddies have been hypothesized as a mechanism for vertical nutrient pumping into the euphotic zone, but the full range and magnitude of biogeochemical impacts by eddies remain uncertain. We evaluated a cyclonic eddy located near Bermuda for its effect on water column biogeochemistry. In the density range σ θ 26.1 to 26.7, an eddy core with anomalous salinity, temperature, and biogeochemical properties was observed, suggesting that the eddy was not formed with local water (i.e., not formed of the waters surrounding the eddy at the time of observations), hence complicating efforts to quantify biogeochemical processes in the eddy. We combined conservative hydrographic tracers (density versus potential temperature and salinity) and quasi-conservative biogeochemical tracers (density versus NO, PO, and total organic carbon) to propose the origin of the eddy core water to have been several hundred kilometers to the southeast of the eddy location at sampling. By comparing the observed eddy core's biogeochemical properties with those near the proposed origin, we estimate the net changes in biogeochemical properties that occurred. A conservative estimate of export was 0.5 ± 0.34 mol N m−2 via sinking particles, with export occurring prior to our period of direct observation. Our results suggest that biogeochemical signals induced by mesoscale eddies could survive to be transported over long distances, thus providing a mechanism for lateral fluxes of nutrients and AOU (apparent oxygen utilization). Given that the proposed source area of this eddy is relatively broad, and the eddy-mixing history before our sampling is unknown, uncertainty remains in our assessment of the true biogeochemical impact of mesoscale eddies in the gyre.en_US
dc.description.sponsorshipSupport for the EDDIES project came from the U.S. National Science Foundation. D.J.M. was also partially supported by NASA.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2008JC004840
dc.subjectMesoscale eddyen_US
dc.subjectBiogeochemical cyclesen_US
dc.subjectNutrientsen_US
dc.titleTracer-based assessment of the origin and biogeochemical transformation of a cyclonic eddy in the Sargasso Seaen_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2008JC004840


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