Home on the rig

By Fred Pearce CORALS thought to be at risk from oil exploration have been found thriving on the legs of oil platforms. The discovery, made on a recent survey in the North Sea, raises new questions about how rigs should be decommissioned. Marine biologists found the coral Lophelia pertusa growing on support towers and tanker moorings around the Beryl Alpha platform in the northern North Sea, just a few hundred metres from where drilling has been taking place since the mid-1970s. “We saw hundreds of coral colonies,” says Murray Roberts of the Dunstaffnage Marine Laboratory near Oban in Scotland. Roberts and his colleagues used a remotely operated mini-submarine to examine and sample the corals. “From the size of the colonies, many are likely to be about 20 years old,” he says. The coral usually lives in deeper water and needs bare rock on which to anchor itself. “These oil platforms seem to provide valuable substrates on which coral can grow,” Roberts suggests, “There is very little hard rock for them in the North Sea proper.” He believes that there are likely to be many more coral colonies on other artificial structures in the oil fields. Norwegian engineers breaking up Shell’s infamous Brent Spar storage platform have found it covered in “hundreds of kilograms of corals”, according to Roberts. “The implications are obviously important in drawing up a really green programme for decommissioning these rigs.” Deep-sea corals such as Lophelia are protected under the European Union’s habitat directive. Ironically, the environment group Greenpeace has recently highlighted Lophelia as likely to be threatened by hydrocarbon exploration in the nearby waters of the North Atlantic. Environmentalists have demanded the complete removal of redundant platforms and other North Sea structures, and last month Phillips Petroleum announced plans for the largest ever programme to remove rigs from its Ekofisk field. But that strategy may not be the best environmental solution, says Roberts. Like their tropical counterparts, corals in colder and deeper waters play host to hundreds of other species of invertebrates and act as nurseries for fish. The oil companies, which have helped fund this research, are clearly keen to publicise the findings, says Roberts. But he cautions that none of this necessarily makes oil production good for marine life as a whole. A study published last week by the Centre for Environmental and Risk Management at the University of East Anglia highlights the pollution caused by drill cuttings from production platforms. “Some drilling platforms leave behind 50 000 tonnes or more of cuttings,” says the study’s author Alastair Grant. Loaded with hydrocarbons and heavy metals,
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