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.
Located in
Library
/
RBINS Staff Publications 2022
This study investigates the long-term impacts of offshore wind farms (OWFs) on macrobenthic communities at a far distance (250-500 m) from wind turbines in the C-Power offshore wind farm, on the ThorntonBank (Belgian Part of the North Sea) over a time span of 15 years (2005- 2020). We anticipated that due to the changes in hydrodynamics around wind turbines, together with the increase in depositional flow of faecal pellets produced by filter-feeding epifauna living on the foundation of the wind turbine, there will be an increase in macrobenthic abundance and species richness, as well as a shift in macrobenthos community composition. We also hypothesized that owing to fishery exclusion in offshore wind farms concession areas the ThorntonBank (impact area) and GooteBank (reference area) would grow apart from each other in terms of abundance and species richness, as well as in terms of species composition. Our 15 years analysis supported the hypothesis of an increase in macrobenthic abundance and species richness as fine sediment fraction and total organic matter content increase within the sediment of OWFs. The appearance and subsequent increase in Terebellidae sp. and Ophelia borealis suggested a shift in macrobenthos community composition when compared to the baseline study of 2005. However, changes in macrobenthic abundance, species richness and species composition were observed on both sandbanks, suggesting that either human activities that once took place on the GooteBank affected the communities there, or adding wind turbine does not generate strong impacts on macrobenthic communities. The observed fluctuations over the years could then be due to normal fluctuations in macrobenthos, or that other factors are at play such as climate change. However, in order to confirm these statements, additional studies on macrobenthos within the Belgian Part of the North Sea should be done on the long term. Further analysis should also be carried out in order to confirm the potential shift from a Nepthys cirrosa community toward an Abra alba community
Located in
Library
/
RBINS Staff Publications 2022
