Origin and fate of a bloom of Skeletonema costatum during a winter upwelling/down welling sequence in the Ria de Vigo (NW Spain)

The costal upwelling system of Ria de Vigo (NW Spain) was monitored during 10 d period to study onset development and decay of winter bloom of Skeletonema costatum which is a common feature there. It is observed that under winter thermal inversion condition onset occurred at upwelling favorable 1/2 week period followed by subsequent 1/2 week of development of bloom followed by down welling which forced the decay of bloom in the next 1/2 week period.