FEEDBACKS BETWEEN BENTHIC CARBON MINERALIZATION AND COMMUNITY STRUCTURE - A SIMULATION-MODEL ANALYSIS

A simulation model was constructed as a means to establish and test ca usal links between organic carbon mineralisation and community structu re in a generalised sublittoral, soft-bottom, infaunal, temperate, coa stal, marine, benthic community. Two hypothesised positive feedbacks w ere explicitly included: bioturbation by macrofauna and sulphide accum ulation and toxicity to aerobic organisms, that link benthic organisms and the sediment chemical environment. The magnitude and dynamics of bacterial, meiofaunal and macrofaunal biomasses, and benthic O-2 consu mption simulated over a seasonal regime were reasonable compared with field data. CO2 production was generally underestimated, yet within th e range of published, empirical values, and the dynamics compared well with empirical data. Steady state simulations indicated a reasonable and ecologically explicable collective behaviour, such as anaerobic pr ocesses dominating total carbon mineralisation and sulphide oxidation accounting for the majority of benthic O-2 consumption at high carbon input levels. Sensitivity analysis of selected model parameters indica ted that the positive feedbacks of bioturbation and sulphide toxicity were more important than other selected parameters in determining the model outcome. (C) 1998 Elsevier Science B.V. All rights reserved.