In line with the European Green Deal, the European Commission has adopted strategies and guidelines with ambitious visions for the offshore renewable energy sector and aquaculture sector. Aligned with this vision, the EU-funded ULTFARMS project aims to advance low trophic aquaculture systems, supporting their integration within offshore wind farms, while safeguarding the environment, minimising carbon footprint and addressing commercial viability. As part of the project, we modelled large-scale cultivation of sugar kelp and/or blue mussels, co-located within offshore wind farms in the North Sea, under climate change.
We used a 3D coupled hydrodynamic, water quality and ecological model of the Northwest European Shelf: the Dutch Continental Shelf model – Flexible Mesh (DCSM-FM). The DCSM-FM contains modules that simulate the growth dynamics of sugar kelp and blue mussels, including their interaction with the environment. The model also simulates the interaction of the wind turbines on ambient flow.
The DCSM-FM was nested in outputs from the global CMCC Earth System Model (CMCC-ESM2) for the SSP5-8.5 climate scenario. Aligning with the 2050 horizon of the European Green deal, we ran the simulations under the projected climate conditions around 2050. The climate change scenario, SSP5-8.5, is a scenario that was described by the IPCC. It is the scenario that arises from socio-economic trends described in the Shared Socio-economic Pathway 5, that lead to a radiative forcing of 8.5 Wm-2 in 2100. Of the five SSP-based scenarios, SSP5-8.5 is the scenario with the highest amount of greenhouse gases.
The model provides insight into the effect of large-scale cultivation on the environment, such as changes in ambient nutrient availability and primary production. In addition, the model shows effects of wind turbines on current patterns, stratification regimes, fine sediment dynamics and any consequential changes in the growth dynamics of sugar kelp and blue mussels. Our findings help to identify the potential future impacts of large-scale seaweed and shellfish production on the North Sea ecosystem, and how climate change might alter the suitability of offshore wind farms for multi-use.