In this study, generic models for the assessment of marine aquaculture in relation to marine protected N atura 2000 areas (N2000) was developed and applied , in accordance with the guidance on the European Habitat Directive and the biological quality elements used in the EU Water Framework Directive.
The habitat assessments involved five consecutive years of full-scale 3D hydrodynamic and biogeochemical modelling, use of satellite images/Earth observation data (EO) of benthic vegetation and extensive GIS mapping . The complex was validated and documented using five years monitoring data from the Danish NOVANA program (the national monitoring program for the aquatic environment and nature).
The hydrodynamic model includes an integrated dynamical description of waves, currents, shear stress, salinity, and temperature. The biogeochemical model includes an integrated dynamical description focusing on pelagic and benthic impacts. It also comprises an advection/dispersion module.
For the study of eutrophication impacts, the biogeochemical model includes state 80 variable s describing the release and fate of inorganic and organic of nutrients (nitrogen and phosphorus) and organic carbon to the pelagic and seabed. The pelagic part of the model describes changes in concentrations and processes related to phytoplankton, zooplankton, nutrients, dead organic matter (detritus), and dissolved oxygen, arising from the fish production . The benthic part of the model describes spill , deposition and fate of organic nutrients and carbon from fish cages. At the seabed, waste is mineralized and/or resuspended by shear stress (sum of wave and current energy).
The present study illustrates that advanced biogeochemical models is a key toll for scienced based and scientifically sound environmental impact assessment of marine aquaculture. Further, the study illustrates how aquaculture can be environmentally sustainable and compatible with nature protection provisions, if developed and located with respect to the biological structure, function and integrity of the protected habitats and species.