Eg. Fermin et al., SHORT-TIME SCALE DEVELOPMENT OF A GYMNODINIUM-CATENATUM POPULATION INTHE RIA-DE-VIGO (NW SPAIN), Journal of phycology, 32(2), 1996, pp. 212-221
Wind direction and fresh water runoff determine the circulation patter
n of the Ria de Vigo (NW Spain), which in trm influence the selection
and distribution of its phytoplankton populations. Coastal winds with
a south-southwesterly component reverse the positive estuarine circula
tion in the Ria, causing an off-shore to in-shore flow of surface wate
rs and, consequently she outflow of inner waters via deeper layers. We
found that this reversal imposed a selective force on the phytoplankt
on population: diatoms, which could not counteract the sinking movemen
t of the surface waters, were diminished, while dinoflagellates remain
ed in the water column. From the end of September to the beginning of
October 1993, an accumulation of Gymnodimium catenatum Graham was obse
rved coinciding with an intrusion of coastal water induced by westerly
winds which provoked a reversal in the circulation of the Ria. The sl
ow reestablishment of the positive estuarine circulation pattern, whic
h was due to a weak coastal upwelling and considerable fresh wafer run
off allowed the population of G. catenatum to flourish.