Temporal variations in benthic communities and their response to physicochemical forcing: a numerical approach

Abstract

A generic complex ecological model, the European Regional Seas Ecosystem Model (ERSEM), was applied to a shallow lagoon system in the Eastern Mediterranean. Model results depicting the seasonal variation of nutrients and Chl-α in the water column, as well as three benthic functional groups (suspended feeders, deposit feeders, and benthic carnivores), are validated with in situ data. The likely effect of a technical intervention (river input) increasing the freshwater nutrient inputs on ecosystem functioning is also investigated. Detailed annual carbon fluxes and benthic fauna biomasses are calculated, before and after the river input. The importance of external physical/chemical forcing on the pelagic system and its subsequent effect on the benthic system are demonstrated. Model experiments indicate the shift of the ecosystem from nitrate limitation to predator control with external inputs. Model experiments also show a significant increase in the amount of carbon entering the benthic system through the activity of filter feeders when river inputs are implemented.