The expansion of offshore wind farms in the North Sea is making progress. But the consequences for the marine environment they are built in have not yet been fully researched. Scientists at the Helmholtz-Zentrum Hereon have already provided valuable insights into the effects of wind farms in past studies. In their latest publication, they now show that large-scale wind farms can strongly influence marine primary production as well as the oxygen levels in and beyond the wind farm areas. Their results were published in the scientific journal Communications Earth & Environment.
The latest study, led by Dr Ute Daewel of the Institute of Coastal Systems – Analysis and Modeling, now confirms that these impacts also lead to an altered spatial distribution of marine ecosystem components. This includes the distribution of nutrients, phyto- and zooplankton as well as biomass in the sediment, the food basis for many bottom-dwelling organisms. In the model study, the team assumed the planned large-scale offshore wind farms in the North Sea. For deeper marine areas, the researchers thus found that the amount of biogenic carbon in the sediment would increase locally by 10 percent and the oxygen concentration, in an area where it is already very low, could decrease even further.
“Our results show that the extensive expansion of offshore wind farms will have a significant impact on the structuring of marine coastal ecosystems. We need to better understand these impacts quickly and also take them into account in the management of coastal ecosystems,” concludes Ute Daewel. (Source: Hereon press release)
Read the complete Hereon press release:
==> Offshore wind farms change marine ecosystems
Daewel, U., Akhtar, N., Christiansen, N., & Schrum, C. (2022): Offshore wind farms are projected to impact primary production and bottom water deoxygenation in the North Sea. Commun Earth Environ 3, 292 (2022), doi:10.1038/s43247-022-00625-0
Abstract:
The wind wake effect of offshore wind farms affects the hydrodynamical conditions in the ocean, which has been hypothesized to impact marine primary production. So far only little is known about the ecosystem response to wind wakes under the premisses of large offshore wind farm clusters. Here we show, via numerical modeling, that the associated wind wakes in the North Sea provoke large-scale changes in annual primary production with local changes of up to ±10% not only at the offshore wind farm clusters, but also distributed over a wider region. The model also projects an increase in sediment carbon in deeper areas of the southern North Sea due to reduced current velocities, and decreased dissolved oxygen inside an area with already low oxygen concentration. Our results provide evidence that the ongoing offshore wind farm developments can have a substantial impact on the structuring of coastal marine ecosystems on basin scales.