Modelling the Deposition and Biological Effects of Organic Carbon from Marine Sewage Discharges

The impacts of particulate organic carbon on marine benthic ecosystems have been modelled mathematically. The principal model (BenOss-Biological Effects and Organic Solids Sedimentation) links various modules: particle tracking; a resuspension module which accounts for both deposition and resuspension of carbon at the sea bed; a chemical module which removes organic carbon according to its degradability using the G-model; and a biological module which predicts benthic community structure on the basis of carbon availability. The model predicts the benthic effects of reducing carbon input. Observations of benthic community structure are related to predictions of carbon deposition arising from a discharge. Predictions of carbon deposition are correlated with changes in total species abundance, abundance of subsurface deposit-feeders and suspension-feeders.