Temporal variation of polychaetes from Picinguaba and Ubatumirim bights (southeastern Brazil)

This study describes the temporal variability of the polychaetes between Ma y 1993 and April 1994, at two monthly intervals at seven stations from 3 to 17 m depth in two small bights located in southeastern Brazil (Sao Paulo S tate). Maximum densities, biomass and richness of polychaetes were recorded in late spring (November) and summer (January). The lowest values were obs erved in winter (July) and early spring (September). The surface dwelling s pecies of the families Spionidae, Cirratulidae, Pilargidae, Poecilochaetida e and Paraonidae were the main indicators of the temporal variability obser ved in the macrofauna community structure. The temporal distribution patter ns were associated to the hydrodynamic processes present in the study area. The occurrence of cold fronts, more intense and frequent in winter, result ed in bottom re-suspension and extensive mortality of the surface life form s from shallow areas. Under these conditions, burrowing infaunal species or carnivorous species can predominate. The penetration of cold water masses during summer increased the concentration of nutrients and the recruitment of larval and juveniles.