Hydrodynamic properties and smallscale turbulence related to different hab events in Alfacs Bay (NW Mediterranean)

Abstract

Different laboratory experiments have shown the particular biological responses of many dinoflagellate species to small-scale turbulence. However, the relevance of these observations has been rarely tested in the field. In this work we characterized the environmental physical conditions during blooms of two different species, the ichthyotoxic dinoflagellate Karlodinium veneficum occurred on June-July 2007 and the diatom Pseudonitzchia spp. occurred in October 2007 in Alfacs Bay. Over the first bloom event, velocity data were almost continuously recorded by a 2MHz acoustic Doppler current profiler deployed on a fixed station (6 m depth). Additional physical (using a CTD and a SCAMP microstructure probe) and biological (chlorophyll concentration, phytoplankton species composition) parameters were obtained from several sampling points. Meteorological data were provided by a nearby station. During the Pseudonitzchia spp. bloom, only microstructure and biological data were collected along 5 days. We will show our preliminary results on the different scenarios under which both events occurred