A numerical study of the benthic-pelagic coupling in a shallow shelf sea (Gulf of Trieste)

A coupled physical-biogeochemical 1D model (BFM-POM 1D) with an intermediate complexity benthic formulation was used to carry out sensitivity tests on the coupling parameters (sedimentation and diffusion at the sediment-water interface). Moreover, a mechanistic experiment was designed to investigate the role of filter feeders in regulating the biogeochemical state of the system in a coastal sea. Best reference parameters of sedimentation and diffusion were chosen from the sensitivity experiments carried out based on available observations. The mechanistic experiment revealed the importance of filter feeders' role in trapping pelagic organic matter and regulating benthic-pelagic nutrient fluxes, as well as controlling pelagic primary production. The model demonstrated to be able to qualitatively reproduce the biogeochemical characteristics of the system and adapt to different trophic configurations. The results shown are encouraging and foresee its possible use as a tool to study causal relationships and help in finding solutions for management issues.