Artificial hard substrate colonisation in the offshore Hywind Scotland Pilot Park 

Abstract

Abstract. Artificial substrates associated with renewable offshore energy infrastructure, such as Floating Offshore Windfarms, enables the establishment of benthic communities with similar diversity species composition to that of naturally occurring rocky intertidal habitats. The size of the biodiversity impact and the structural changes on benthic habitats will depend on the selected locations. The aim of the study was to assess colonisation, zonation, quantify diversity and abundance, and identify any non-indigenous species of fauna and flora present within the wind farm. This article is based on work undertaken within the offshore floating Hywind Scotland Pilot Park, the first floating offshore wind park established in the world, located approximately 25 km east of Peterhead, Scotland. The floating pilot park is situated in water depths of approximately 120 m with a seabed characterised predominantly by sand and gravel substrates with occasional patches of mixed sediments. The study utilised a Work Class Remotely Operated Vehicle with a mounted High Definition video camera, deployed from the survey vessel M/V Stril Explorer. A total of 41 structures, as well as their associated subcomponents, including Turbines (Substructures), Mooring Lines, Suction Anchors and Infield Cables, were analysed with regards to diversity, abundance, colonisation, coverage and zonation. This approach provides comprehensive coverage of whole structures in a safe and time-saving manner. Eleven phyla were observed with a total of 121 different taxa, macrofauna as well as macro- and filamentous algae, identified on the different structures. The submerged turbines measured approximately 80 m in height and exhibited distinct patterns of zonation. Plumose anemone Metridium senile and tube building fan worm Spirobranchus sp. dominated the bottom and mid-sections (80 m–20 m) of the turbines while kelp and other Phaeophyceae with blue mussel Mytilus spp. dominated top sections of the turbines (20 m–0 m).

Sampling hard substrates in Dutch offshore wind farms : work plan towards an offshore wind farm hard substrate sampling & monitoring programme in the Netherlands [MONS-project ID46]

“…Although video methods have successfully been used to detect the presence of large invertebrates on offshore structures (Karlsson et al, 2021;Schutter et al, 2019;van der Stap et al, 2016), these methods cannot quantify nor identify the benthic community in high detail since most species remain unseen as they are too small to be detected on video or are present out of camera view covered by other species. Scraping and/or suction tools for ROVs are available on the market, e.g.…”