Benthic biodiversity on old platforms, young wind farms, and rocky reefs

Abstract

The introduction of artificial hard substrates in an area dominated by a sandy seabed increases habitat available to epifouling organisms. To investigate this, samples were taken on old offshore oil and gas platforms, and data were compared with data of a young wind farm and a natural reef. Depth, sampling date, abundance of Mytilus edulis, Psammechinus miliaris, Metridium dianthus, and the presence of Tubulariidae and substrate (rock or steel) all correlated with species richness. Multivariate analysis showed a large overlap in communities on steel and rock and between the wind farm and platforms. The community changed over a gradient from deep rocks to shallow steel substrate, but no strong community differentiation was observed. Deep steel was more similar to natural rocks than shallow steel. When an artificial reef is intended to be colonized by communities similar to those on a natural reef, its structure should resemble a natural reef as much as possible.

Marine stepping‐stones: Connectivity of Mytilus edulis populations between offshore energy installations

“…Here, we used an indigenous species as model organism to test the concept of marine stepping-stones in the North Sea. In that region, nonindigenous species such as the Japanese amphipod Caprella mutica were found at the same offshore energy installations (Coolen et al, , 2018. The spread of native and non-native species depends largely on reproductive parameters and dispersal strategies.…”

“…Marine stepping‐stones can be important for the distribution of native species such as Caryophyllia smithii (Coolen, Lengkeek, et al, ), Porifera sp. (van der Molen et al, ) and Desmophyllum pertusum (Henry et al, ) and most species present on offshore artificial reefs in the North Sea are indigenous for the area (Coolen et al, ; De Mesel et al, ). However, the stepping‐stone effect might also contribute to a faster distribution of nonindigenous species (Adams et al, ; IPIECA, ; Macreadie, Fowler, & Booth, ).…”

“…These artificial hard substrates include nearshore elements such as jetties, dikes and beach groins, as well as offshore structures such as oil and gas platforms, wind turbines and buoys. Growth of hard-substrate flora and fauna on them is typically abundant (Coolen et al, 2018;De Mesel, Kerckhof, Norro, Rumes, & Degraer, 2015;Krone, Gutow, Joschko, & Schröder, 2013). An increase in connectivity for these species is one of the many kinds of effects these structures are expected to have on natural ecosystems (Adams, Miller, Aleynik, & Burrows, 2014).…”

Ostrea edulisat shipwrecks in the Dutch North Sea

“…During visits of over 100 ship wrecks between 2010 and 2019 by the same group of wreck divers, no other live flat oysters were observed offshore (personal observations by the authors), with exception of locations in the south of the Netherlands and Belgium (Kerckhof et al, 2018). Furthermore, recent investigations of fouling communities on oil and gas structures near shipwreck #3251, did not reveal any flat oysters (Coolen et al, 2018), nor did a study of rocky reefs in the Borkum Reef grounds near the Gustav Nachtigal wreck (Coolen et al, 2015a).…”

Upscaling positive effects of scour protection in offshore wind farms : Quick scan of the potential to upscale positive effects of scour protection on benthic macrofauna and associated fish species

“…The introduction of artificial hard substrates by placing wind turbine foundations and scour protection on the seabed facilitates epibenthic species and associated benthic fish (Bouma and Lengkeek, 2013;Coolen et al, 2018b;Lindeboom et al, 2011;van Hal et al, 2017). Although these hard substrates cover the existing sandy seabed, most likely killing a significant part of the local benthic infauna, the net effect may be considered as positive since it increases local biodiversity by allowing colonisation of species that would otherwise be unable to populate the area.…”