Biogeochemical marine ecosystem models I: IGBEM - a model of marine bay ecosystems

Abstract

The Integrated Generic Bay Ecosystem Model (IGBEM) is presented. It is a coupled physical transport-biogeochemical process model constructed as a basis to explore the effects of model structure and complexity. The foundations for the model are two existing models, the European Regional Seas Ecosystem Model II (ERSEM II) and the Port Phillip Bay Integrated Model (PPBIM). Additional functional groups (such as benthic herbivorous invertebrates) and modules (dealing with sediment chemistry and mixing) have been incorporated or modified to ensure a more complete representation of temperate bay ecosystems and their processes, and a seamless amalgam of ERSEM II and PPBIM. The standard form of the entire model compares well with real ecosystems, such as Port Phillip Bay in Australia, and conforms to general ecological checkpoints such as the expected Sheldon Spectrum and Monbet's relationship between chlorophyll a and dissolved inorganic nitrogen. The model also produces spatial zonation and long-term cycles characteristic of natural systems. Despite the model taking a generalised biomass per functional group form, it captures well the system dynamics and allows for exploration of the effects of ecological driving forces such as predation and competition.