Protecting the marine environment whilst installing offshore windfarms: the effect of scour protection layers on benthic biodiversity

The North Sea will soon see the installation of a higher number of wind turbine foundations, greatly expanding the habitat options for reef species. These offshore structures constitute a new, artificial, hard substratum habitat on the Belgian continental shelf, where the seafloor is primarily made up of muddy and sandy sediment. The possibility of co-designing offshore wind farms with more microhabitats through increasing habitat complexity is one method for the multiple uses of wind farms. This method is known as nature-inclusive building. The structure and dynamics of ecological communities are significantly influenced by habitat complexity. Hence, an increased complexity frequently results in greater species variety and abundance. The objective of this study was to investigate whether adding complexity to the scour protection layer (SPL) increased the diversity and functionality of the ecosystem already present at the bottom of wind turbines (macrobenthos community). To study this, three different variables of 76 species were analysed: richness, biomass, and abundance. Despite being the first time to manipulate the SPL of wind farms, it has been possible to observe and demonstrate that the complexity of these structures affects the ecosystem’s richness. Of the four different treatments, a greater number of species were observed in the most complex ones (3 and 4) compared to the others. In addition, although there were no significant differences, trends of higher biomass of certain species (belonging to decapods and sea anemones) were observed in the presence of higher complexity. Conversely, the constant presence of amphipods was observed across all the treatments. With this study, we wanted to emphasise the importance of the artificial reef effect of the SPL and, together with the microhabitats that it can provide, if at the time of its construction, an attempt is made from an “eco-friendlier” perspective, combining the knowledge of ingested together with the biological. In addition, it provides more knowledge and understanding of this methodology by improving it and obtaining results more similar to those expected in the future.

RBINS Publication(s), Master thesis

Keywords: habitat complexity, artificial reef, scour protection layer, microhabitats, macrobenthos