Ecological implications of removing a concrete gas platform in the North Sea
Autor: | Joop W.P. Coolen, F. Driessen, Udo van Dongen, Oliver Bittner, Babeth van der Weide, Midas S. Siahaya, Stefan G. Bolam, Wim de Groot, Ninon Mavraki |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
0106 biological sciences
Aquatic Ecology and Water Quality Management Population Biodiversity Artificial reef Aquatic Science Gas platform Oceanography 010603 evolutionary biology 01 natural sciences Abundance (ecology) Epifouling Onderz. Form. B education Reef Ecology Evolution Behavior and Systematics Seabed Trophic level Hydrology Biomass (ecology) geography education.field_of_study geography.geographical_feature_category 010604 marine biology & hydrobiology Business Manager projecten Midden-Noord Foundation (engineering) Species diversity Aquatische Ecologie en Waterkwaliteitsbeheer Benthic biodiversity Benthic zone Environmental science Box corer Submarine pipeline Gravity-based structure North Sea Business Manager projects Mid-North |
Zdroj: | Journal of Sea Research 166 (2020) Journal of Sea Research, 166 |
ISSN: | 1385-1101 |
Popis: | Artificial structures such as offshore oil and gas platforms can significantly alter local species communities. It has been argued that this effect should be considered during decisions over their removal during decommissioning. In the North Sea, leaving such structures in place is prohibited but derogations are allowed for large concrete installations. To assess removal options for one such installation, the Halfweg GBS (gravity-based structure) a concrete platform foundation off the Dutch coast, we studied the resident fouling macrofauna community. The faunal structure, biomass and trophic composition of the Halfweg was then compared with those from the surrounding seabed sediments, other local artificial structures and a natural rocky reef.In total, 65 macrofaunal species were observed on the concrete (52 species), steel legs (32) and surrounding rock dump (44) of Halfweg. Mean Simpson diversity per sample was highest on the rock dump (0.71) but concrete (0.54) and steel (0.60) of the GBS were lower than seabed (0.69). Ten of the species observed on the concrete were not reported on other substrates while 10 of the species were also observed in the surrounding seabed. The GBS structure was numerically dominated by Arthropoda which comprised 98% of the total abundance. Mean ash free dry weight (AFDW) was significantly higher (p2) than in the surrounding seabed (65 g AFDW per m2). Over 94% of the biomass on Halfweg consisted of the plumose anemone Metridium senile. While common on other reefs, this species was absent from the surrounding seabed. Macrofaunal feeding mechanisms of the concrete and rock dump communities on the GBS were similar to those of nearby sediments, although these differed from those on the Halfweg steel legs. Therefore, the presence of Halfweg alters the local community feeding modes. Multivariate analysis revealed that taxonomic structure of the GBS and other artificial structures significantly differed from that of the sedimentary habitats. Low numbers of non-indigenous species on Halfweg indicated that the structure does not act as a stepping stone for species invasions.Our data show that the Halfweg structures significantly increase local biodiversity and biomass. Removal of the concrete and steel legs of the GBS (leaving the rock dump) will significantly reduce local macrofauna biodiversity. The long-term impact on macrofaunal biomass is low. Leaving the complete Halfweg structure in place will result in an enriched local macrofaunal biodiversity and feeding mode diversity. |
Databáze: | OpenAIRE |
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