Pelagic–benthic coupling in a subtidal system of the North-Western Mediterranean

Abstract

Suspended particulate matter, zooplankton, and macrobenthos dynamics were investigated in a shallow area of the Ligurian Sea (north-west Mediterranean) characterized by wide temporal variability over an annual cycle. As indicated by multivariate analyses, the seasonal dynamics can be summarized as follows: (1) a late winter–early spring phytoplankton bloom followed by high zooplankton and macrobenthos densities during the spring months; (2) low-quality particulate suspended matter in summer, and an increase in the importance of zooplankton taxa with a wide range of feeding strategies, a decrease in macrofaunal abundance, and an increase in deposit-feeders and predators; and (3) a second phytoplankton bloom in autumn, followed by an increase in copepod density and a low macrofaunal abundance. In conclusion, pelagic and benthic communities in the coastal area of the Ligurian Sea mainly seem to be controlled bottom-up. Our results suggest that the quality of the particulate organic matter may play an important role in determining the temporal changes of both plankton and benthic assemblages, while the direct influence of other environmental features (such as sediment grain size) is relevant only for some macrobenthic taxa (e.g. crustaceans).