Biogeochemical and meteorological patterns of an upwelling-downwelling process in the Northern Galician Rias (NW Iberian Peninsula)

Abstract

The oceanographic characteristics in the water column of the Northern Galician Rias (NW Iberian Peninsula) were studied during a summer upwelling event (July 2008; R/V Mytilus) and compared with the patterns measured under a subsequent downwelling process (August 2008; R/V Lura). Both phenomena were characterized in situ using thermohaline variables, nutrients salts and chlorophyll concentrations, and phytoplankton abundances measured at sections located in the Rias of Viveiro, O Barqueiro and Ortigueira. Moreover, it were also considered the Ekman transport at five control points calculated with wind data from QuikSCAT satellite, upwelling intensity estimated from upwelling index values calculated at a point located at 43ºN and 11ºW using the average daily geostrophic winds and SST maps (NASA GHRSST satellite). Data information during the upwelling event showed the intrusion of water mass into the ria associated with the Eastern North Atlantic Central Water (ENACW) to develop a red tide some weeks after during the downwelling cond