For a whole summer, the Gulf of Mexico was at the centre of the global news cycle. Day and night, live tickers soared upwards as the oil gushing out of the Deepwater Horizon rig refused to relent. Finally, 87 days after the initial explosion which killed 11 workers and started the oil crisis, BP, the operator of the rig, was finally able to seal it shut.
Five years on, and mentions of the incident in the news since the plugging of the leak have largely been restricted to reporting on US court decisions regarding fines potentially being levied at BP. Yet the Gulf of Mexico, and the wildlife which has traditionally called it home, has not been able to move on so easily.
‘Five years later, wildlife in the Gulf are still feeling the impacts of the oil spill,’ says Collin O’Mara, president and CEO of the National Wildlife Federation. ‘The science is clear that this is not over, and sea turtles, dolphins, fish, and birds are still suffering from the fallout.’
“Between 27,000 and 65,000 turtles are estimated to have died in 2010”
O’Mara refers to a new National Wildlife Federation report, Five Years and Counting: Gulf Wildlife in the Aftermath of the Deepwater Horizon Disaster, which outlines how many species have had difficulties in the years since the disaster.
It highlights trends such as dolphin deaths on the Louisiana coast being four times the historic rate, as well as the significant damage done to five different coral colonies in the area, and declines in the annual numbers of Kemp’s ridley sea turtle nests in the years since the spill. Between 27,000 and 65,000 turtles are estimated to have died in 2010. Other species adversely affected include brown pelicans, laughing gulls, speckled seatrout, red snappers and sperm whales.
O’Mara and other scientists at the NWF regularly call for fines charged to BP to be used to help with the restoration of the Gulf of Mexico area.
However, the environmental damage wasn’t entirely the fault of the initial oil spill.
One method of clearing the oil involved spraying of the dispersant Corexit 9500A. Unfortunately, subsequent tests have shown Corexit 9500A to be more toxic to cold water coral than oil. A recent study, Response of deep-water corals to oil and chemical dispersant exposure, conducted by researchers from Temple University and the Pennsylvania State University, and published in the journal Deep Sea Research Part II, found that the seven million litres of dispersant used in the aftermath of the oil crisis could have significantly worsened the impact of the spill.
‘Applying the dispersant at depth was a grand experiment being conducted in real-time,’ says Erik Cordes, an author on the study, and associate professor of biology at Temple University. Cordes suggests that the oil and dispersant mixing together could have been a truly toxic combination. ‘It doesn’t take as much dispersant to kill coral as it does oil,’ he concluded.
And these chemicals weren’t just bad news for coral. Further studies on Corexit 9500A in another report showed it to be harmful to marine gills, as well as to human lungs. An additional study, undertaken by the University of Alabama and published in the journal PLOS ONE, emphasises not only the damage this chemical might have done to wildlife, but also to the 48,000 people who were actively involved as part of the ‘clean up’ effort.
However, it isn't entirely bad news about the wildlife of the Gulf, at least in terms of its place in the food chain. Despite recent surveys finding that only just over 50 per cent of the local area would feel comfortable eating seafood from the affected area, a recent survey by the University of Florida found no noticeable impact on the seafood in the region.
‘Seafood appears as safe to eat now as it was before the spill,’ says Dr. Andrew Kane, associate professor of environmental and global health and director of the Aquatic Pathobiology Laboratory at the University of Florida.
Kane and his team were particularly worried about polyaromatic hydrocarbons (PAHs), a component of oil which can accumulate in plankton and microorganisms and can be ingested by fish and other seafood. More than a thousand fish, shrimp, oysters and blue crabs from the Gulf of Mexico area were sampled and tested and found to have no elevated contaminant levels. In fact, three-quarters of those sampled had no PAH contaminants in them at all.
The environment around the Gulf of Mexico has clearly suffered considerably in the five years since the Deepwater Horizon disaster. But while the University of Florida survey suggests the wildlife may not be suffering as badly as first thought, the National Wildlife Federation report is clear that in many ways, we are just finding out about the long-term consequences of this event. As the report concludes: ‘It may take years or even decades before the full impacts are known, and more research is clearly needed. In the meantime, restoration of the Gulf ecosystem must become a high priority for the nation.’