Carbon flows in a subtidal fine sand community from the western English Channel: a simulation analysis

Abstract

Organic carbon flows through the Plerre Noire fine sand community (Bay of Morlalx, France) are described with a trophodynamic point model. Data collected during several annual cycles are used to calibrate the seasonal vanations of each benthic compartment. Mean annual values of state vanables are correctly simulated. In a first approach, the seasonal variations were simulated using 2 forcing functions: input of energy and temperature Influence. In a second run, spawning and recruitment effects were introduced as regulating factors for the macrobenthic compartments. The result~ng annual carbon budget synthesizes the information w e have on this common type of ecosystem. Phytoplankton production represents the major food supply to the benthlc system a n d the importance of pelagic-benthlc coupllng in this area is confirmed. A large proportion of the carbon input IS consumed by bacteria which is the main trophic source for meiofauna. Melofauna is a n important llnk between the bacteria + detritus and the carnivore level, and cannot be considered as an Independent food web The significance of regulation factors such as spawning and recruitment processes in the dynamics of the macrofauna IS explored.