Abstract:
Introduction: Seasonal upwelling is a displacement offshore of surface seawater and replacement by cool deeper
water with higher nutrient levels by the influence of the wind. On the north Pacific coast of Costa Rica the
upwelling is present from December to April.
Objective: Within this seasonal upwelling area, Salinas Bay was sampled to determine whether the upwelling has
an effect on the diversity, composition, and trophic guilds of the soft-bottom benthic community.
Methods: The bay was visited during the upwelling and non-upwelling seasons of 2007-2009. A number of six to
nine grab samples were taken in each sampling event.
Results: Richness and abundance were lower in the non-upwelling season and the highest values were observed
at the end of the upwelling. The taxa composition of assemblages varied partially across the seasons, depending
on the upwelling intensity.
Conclusions: The species composition was more diverse and abundant at the end of the upwelling season than at
the start or in the non-upwelling season. Differences in infaunal assemblages during the seasonal upwelling could
be explained by the change in characteristics of the sediment-water interface, nutrients, and sediment movements
that promote the increase of planktonic productivity, and thus food availability.
