There are currently plans to upscale the cultivation of shellfish and seaweed to offshore areas in the North Sea, as part of the envisioned Blue Economy and as a promising option for multi-use of offshore wind farms. Previous research has shown that monopiles of offshore wind farms locally affect hydrodynamics and water quality, influencing local nutrient availability, the light climate and hence primary production. However, there is still limited knowledge on the implications of these changes for aquaculture species growing within offshore wind farms, and how this interaction will change under future climate conditions.
As part of the EU-funded ULTFARMS project, we modelled large-scale cultivation of sugar kelp and/or blue mussels, co-located within offshore wind farms in the North Sea. A state-of-the-art ecosystem model was used to determine the local interplay between offshore wind farms and aquaculture sites under different climate scenarios, including the interaction of the wind turbines with ambient flow. To also include the effects of offshore wind farms on the wave field and hence on fine sediment dynamics, the spectral wave model DCSM-SWAN was employed. The wave model was run for two scenarios with and without wind farms both for historical and future periods.
The SSP5-RCP8.5 climate change scenario, representing highest greenhouse gas emissions, was selected. Policy-driven changes in river input, affecting nutrient loads, were also incorporated. Simulations were run under the projected climate conditions around 2050, in line with the 2050 horizon of the European Green Deal. To assess pure climate change effects, the results were compared with a historical reference period around 2005.
This presentation will provide insights 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 their implications for the growth of sugar kelp and blue mussels. These 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.
Acknowledgment
This project has received funding from the European Union's Horizon Europe research and innovation programme under Grant Agreement No 101093888. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union. Neither the European Union nor the granting authority can be held responsible for them.