Posted on January 11, 2023
A team of German scientists has suggested that offshore wind farms in the North Sea could significantly impact the ecosystem.
The scientists from the Helmholtz-Zentrum Hereon Research Institute used numerical modelling to show how there could be physical disruptions to the marine environment, along with sedimentation and wind flow from turbines.
They forecast sedimentation could increase by as much as ten per cent as a result of transforming wind into electrical power.
Increased sedimentation could occur not only at the offshore wind farm clusters, but may also distribute over a wider region, the scientists say in a paper published in scientific journal, Communications Earth and Environment.
Their 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.
They say that their 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”.
The paper explains that the North Sea is a shallow shelf sea system, in which “the interactions between bathymetry, tides and a strong freshwater supply at the continental coast foster a complex frontal system, which separates well-mixed coastal waters from seasonally stratified deeper areas”.
“The shallow coastal areas and sandbanks combined with stable wind resources make the North Sea an ideal area for renewable energy production and have made the North Sea a global hotspot for offshore wind energy production,” their paper states.
“ The recently negotiated European Green Deal to support the European target to phase out dependence on fossil fuels will further accelerate the development of offshore renewable energy, and a substantial increase of installed capacity (212 GW by 2050) is planned in the North Sea as a consequence to Europe´s strategy to be carbon neutral by 2050,” their paper points out.
They explain that underwater structures, such as foundations and piles, may cause turbulent current wakes, which impact circulation, stratification, mixing, and sediment resuspension
While increased sedimentation could see the North Sea adding more “blue carbon” to its seabed, and phytoplankton productivity may increase as a result of clearer waters in some areas, muddy grounds such as those inhabited by Nephrops or prawns would be negatively impacted.
The authors explain they cannot predict with accuracy which species will benefit and suffer as a result of wind farm developments offshore.
The full paper can be read here