BORIS-2 – a benthic ecosystem model based on allometry

Abstract. We present a model describing the population dynamics of benthic biota, feeding from a common resource that is supplied by a flux of sinking organic carbon arriving on the seafloor. By using allometric relationships for the physiological processes of growth, mortality and respiration, and for food limitation, the model represents the population dynamics of organisms ranging in size from bacteria (10-14 g wet weight C) to large metazoans (103 gwwt C). The effect of temperature on physiological rates is also included. The only forcing information required is the ambient temperature and the rate of supply of sinking organic carbon. The model can be used for, and tuned to, specific locations. However, a parameter set is provided that is generally applicable. The ability of the model to simultaneously reproduce biomass size distributions at five contrasting sites is demonstrated for this parameter set. Other examples of use are also shown, using the model to explore global patterns of benthic biomass, and responding to a change in food supply.