Seasonal budgets of organic matter in the Ubatuba shelf system, SE Brazil. I. Planktonic and benthic components

Abstract

Planktonic and benthic productivity and consumption were estimated to assess the availability of food to higher trophic-level consumers in the Ubatuba ecosystem on the SE coast of Brazil. The study area included waters from 10 to 100 m deep and covered 3800 km². The trophic compartments of the system were established on ecologically or taxonomically related species, considering their relative abundance and similarity of diets and habits. The compartments are phytoplankton, zooplankton, salps, bacterioplankton, cnidaria, polyplacophora, mollusca, carnivorous benthos, detritivorous polychaetes, other detritivorous benthos, penaeidea-caridea, brachyura, and echinodermata. Biomass, production, and consumption were estimated in summer and winter. Plankton biomass, production and consumption were higher in summer than in winter, mainly because of the presence of salps. Primary production was estimated as 1486 g wet weight m^–2 3 months^–1 in summer and 704 g in winter. Total benthic biomass in summer (101 gww m^–2) was twice that in winter (53 gww m^–2), but its production and consumption were similar in both seasons.