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dc.contributor.authorMourino, Beatriz  Concept link
dc.contributor.authorFernandez, Emilio  Concept link
dc.contributor.authorAlves, Mario  Concept link
dc.date.accessioned2010-06-16T17:57:51Z
dc.date.available2010-06-16T17:57:51Z
dc.date.issued2004-04-21
dc.identifier.citationJournal of Geophysical Research 109 (2004): C04020en_US
dc.identifier.urihttps://hdl.handle.net/1912/3654
dc.descriptionAuthor Posting. © American Geophysical Union, 2004. 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 109 (2004): C04020, doi:10.1029/2003JC001990.en_US
dc.description.abstractTwo oceanographic cruises were carried out in the Azores Current/Subtropical Front region in July 1997 and April 1999 to study the seasonal and mesoscale spatial variability in the relationship between the hydrodynamic characteristics of the water column and the distribution of nutrients, phytoplankton biomass, and production. Both the magnitude of chlorophyll-a values and primary production rates as well as their vertical distribution varied sharply associated with subtle changes in seasonal thermal stratification. Successive upwelling and downwelling regions were detected along the track of a cyclonic meander, with maximum ageostrophic vertical velocities of 3 m d−1 and −4 m d−1, respectively, at 375 dbar. Relatively high nitrate concentrations (>3.5 μM) were found associated with denser waters at the center of the meander, where the deep chlorophyll maximum (DCM) uplifted ~20 dbar. Chlorophyll-a concentrations ranged from 0.1 to 0.4 mg m−3, with slightly higher values (>0.35 mg m−3) at the northern side of the current. A significant relationship was not detected between the vertical ageostrophic velocity field and nitrate and chlorophyll-a distributions, which were significantly correlated with the depth of the 16°C isotherm. Vertical advective fluxes of nitrate across the base of the DCM were about 2 orders of magnitude higher than vertical diffusive nitrate transport (−6.6 to 3.7 mmol m−2 d−1 versus 0.01 to 0.07 mmol m−2 d−1). Diffusive nitrate fluxes only account for <10% of the total primary production rates measured in the region.en_US
dc.description.sponsorshipThis study was funded by the European Commission under the CANIGO contract MAS3CT960060 and CICYT. B. Mourin˜o was supported by a FPU fellowship from the Ministerio de Educacio´n y Cultura (Spain).en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2003JC001990
dc.subjectNortheast Atlantic subtropical fronten_US
dc.subjectMesoscale variabilityen_US
dc.subjectAgeostrophic vertical circulationen_US
dc.subjectVertical nutrients fluxesen_US
dc.subjectPhytoplankton biomass and productionen_US
dc.titleThermohaline structure, ageostrophic vertical velocity fields and phytoplankton distribution and production in the northeast Atlantic subtropical fronten_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2003JC001990


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