FN Archimer Export Format PT J TI Satellite and in situ observations of a late winter phytoplankton bloom, in the northern Bay of Biscay BT AF GOHIN, Francis LAMPERT, Luis GUILLAUD, Jean-Francois HERBLAND, Alain NEZAN, Elisabeth AS 1:;2:;3:;4:;5:; FF 1:PDG-DEL-EC-PP;2:PDG-DEL-PB;3:PDG-DEL-EC;4:PDG-DRV-RA-CREMA;5:PDG-DEL-CC; C1 IFREMER, Ctr Brest, F-29280 Plouzane, Brittany, France. EPSHOM, CMO, CM, F-29275 Brest, Brittany, France. CREMA Houmeau, F-17137 LHoumeau, France. IFREMER, F-29187 Concarneau, Brittany, France. C2 IFREMER, FRANCE EPSHOM, FRANCE IFREMER, FRANCE IFREMER, FRANCE SI BREST PORT-EN-BESSIN LA ROCHELLE CONCARNEAU SE PDG-DEL-EC-PP PDG-DEL-PB PDG-DEL-EC PDG-DRV-RA-CREMA PDG-DEL-CC IN WOS Ifremer jusqu'en 2018 IF 1.191 TC 46 UR https://archimer.ifremer.fr/doc/2003/publication-463.pdf LA English DT Article CR GASPROD 1 GASPROD 2 NUTRIGAS PEL 2000 PELGAS BO Thalassa DE ;Bay of Biscay;Coscinodiscus;Algal bloom;Phytoplankton;Ocean colour;Satellite sensing AB A phytoplankton bloom was observed in late winter 2000, on the continental shelf offshore of southern Brittany, in northwestern Bay of Biscay. This bloom appeared initially along the 120-m isobath, in stratified and clear waters, at the interface between the oceanic water and the plumes of southern Brittany rivers (mainly the Loire and Vilaine). The development of the bloom was triggered by favourable meteorological conditions, characterised by solar irradiance reaching the maximum level expected for that period of the year. Outside of the bloom area, the phytoplankton photosynthesis was irradiance limited: inshore, because of the stronger attenuation of the light; offshore, because of the weak stratification. The hydrological conditions at the onset of the bloom were observed in the field, during the oceanographic cruise MODYCOT. However, without SeaWiFS, the only observations related to this major event in the primary production would have been those of the coastal phytoplankton network (REPHY (REseau PHYtoplankton)). Observed initially offshore by SeaWiFS, as early as March 5, 2001, the phytoplankton bloom extended onshore and was observed at REPHY stations by mid-March. On, March 15, fishermen reported that they were handicapped in trawling, the presence of mucilage in their nets carried clogging by very heavy slime. This mucilage has been shown to be produced by the diatom Coscinodiscus and, especially, C. tvailesii. These observations were made as the main bloom was declining. A simple calculation, based upon the SeaWiFS chlorophyll concentration maps observed from March 5-16, shows that phosphate was probably totally depleted offshore, by March 16. The former bloom area appeared very poor in chlorophyll on the SeaWiFS image of April 7, which was the first image available after 3 weeks of an overcast sky. A second cruise undertaken at the end of April confirmed the phosphate depletion and the low chlorophyll concentration in that area. PY 2003 PD JUN SO Continental Shelf Research SN 0278-4343 PU Elsevier VL 23 IS 11-13 UT 000185172400006 BP 1117 EP 1141 DI 10.1016/S0278-4343(03)00088-8 ID 463 ER EF