EMODnet Seabed Habitats contributes to the debate on the decommissioning of offshore infrastructure

This study was published by a group of authors, including representatives from a range of universities and research organisations. The lead author is the University Technology Sydney’s fish ecology lab, which aims to provide novel research to inform on the sustainability of the oceans and their fish populations. They actively engage in public debate on a wide range of issues affecting the marine environment, and also act as a hub for student research training. Their studie

The authors aimed to contribute to the debate on the decommissioning of oil and gas (O&G) and offshore windfarm (OWF) installations in the North Sea, where there is considerable argument for leaving the structures at least partially in place, due to the unique habitat they provide. The authors were therefore interested in understanding the benthic habitats within the North Sea area, in order to study the connectivity between areas of hard substrate, and so required as much data as possible on the locations and extent of benthic marine habitats across the study area. As the study area comprised the regional seas and territorial waters of multiple countries, this posed an additional challenge as data must be in a format allowing for transboundary analysis.    

EMODnet Seabed Habitats' data from across the North Sea were categorised according to substrate type and compared to the locations of offshore O&G and OWF installations within the study area. This information was then used to identify locations in which offshore installations provide unique hard substrate in otherwise soft substrate areas, as well as to determine the connectivity between these installations and areas of natural hard substrate. EMODnet provided publicly available benthic habitat data across the entire North Sea in a format from which the authors were easily able to classify habitats according to their “hardness” for the purposes of this study. The use of this dataset therefore saved the users on staff time, associated costs and resources.

The results of this study fed into the discussion on the potential ecological implications of removing these habitats from areas of primarily soft substrate. The authors argue that in certain areas the complete removal of structures will conflict with other policies regarding the protection and restoration of reef and other hard substrate habitats. The work has also identified key knowledge gaps in terms of ecological considerations which are often not considered in decommissioning policy, with the hope that these will be addressed through further investigations, the scientific training of industry personnel and trial decommissioning projects.