Decommissioned offshore structures could offer only limited ecological benefits, study suggests

Decommissioned offshore structures could offer only limited ecological benefits, study suggests - University of Plymouth

Offshore structure from INSITE project (photo via Plymouth University)

Decommissioned offshore structures offer limited long-term ecological benefits if they are simply left in the ocean to serve as artificial reefs, a new study suggests.

The research, published in the journal Nature Sustainability, saw researchers carry out a comprehensive analysis of existing studies into the environmental impacts of marine artificial structures – including oil and gas platforms and offshore wind farms – all over the world.

It highlighted that such installations can offer some ecological benefits – including increasing the diversity and abundance of fish species – in areas where the seafloor was mostly comprised of sand.

However, there was limited conclusive evidence that oil and gas platforms and offshore wind farms could provide additional substantial benefits if they were left in the sea after being decommissioned.

In particular, the available evidence did not allow the researchers to draw clear conclusions on how the structures compare to natural rocky reef – which limits the ability to establish whether they can serve as artificial reef at all.

As a result, the researchers say more detailed investigations are needed into the best way to manage such structures at end-of-life, as repurposing them into artificial reefs may not provide the intended benefits.

The study was carried out by researchers at the University of Plymouth, Plymouth Marine Laboratory and the Centre for Environment, Fisheries and Aquaculture Science (Cefas).

This study highlights just some of the challenges facing those working on the decommissioning of offshore structures.

With limited existing evidence, it is almost impossible to give a definitive answer as to how best to deal with these platforms and other structures when they reach the end of their lives. For the time being, the best solution might be to deal with decommissioning on a case-by-case basis, but it is clearly something that needs addressing so it can be built into future development plans.

The full study – Lemasson et al: A global meta-analysis of ecological effects from offshore marine artificial structures – is published in Nature Sustainability, DOI: 10.1038/s41893-024-01311-z