Environmentalists and fishers want oil and gas structures in the ocean to be completely removed when they are no longer needed 鈥� but doing so could actually harm marine wildlife. Not only are deep-sea corals thriving on oil and gas rigs in the North Sea, the larvae they release may be helping repopulate damaged natural reefs elsewhere.
The cold-water coral Lophelia pertusa, which grows in the North Atlantic in waters deeper than 80 metres, can form vast reefs hundreds of metres high and hundreds of kilometres long.
Thousands of animals live on or depend on these reefs. For instance, various sharks lay their eggs in them. But many of these reefs have been badly damaged by trawling and while some are now protected, they are isolated and far apart.
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However, small colonies of these corals are thriving on oil rigs in the North Sea, creating havens for marine life. 鈥淭here are corals all over the rigs in the North Sea. They have formed their own ecosystem,鈥� says Lea-Anne Henry of the University of Edinburgh. 鈥淭he animals we are finding associated with the corals on the rigs are identical to what we are finding in the wild.鈥�
Model behaviour
Her team has used computer models that to work out where the coral larvae released from the rigs end up. The models simulate both local currents and the swimming behaviour of individual larvae.
The result show that the larvae from the rigs could be helping recolonise damaged natural reefs across a huge area. They should be reaching the Aktivneset marine protected area off Norway, for instance. The rigs should also be acting as a stepping stones that allow natural reefs to swap coral larvae, and thus to remain genetically diverse and healthy in the long term.
However, the UK is signed up to, old oil rigs are supposed to be completely removed. Environmental groups . And fishing groups also want the structures completely removed, so they can trawl these areas. Henry says the plans for complete removal should be rethought in light of the growing evidence that it would harm wildlife.
Leaving these structures in place would also save taxpayers billions. Oil companies in the UK , and the country now pays out more to oil companies than it receives.
