Deepwater Horizon: Five Years On

The world looked on, horrified and helpless, as thick oil, black as nightmares, spewed out into once pristine waters. A mile beneath the surface of the Gulf of Mexico, oil and gas were being discharged in devastating amounts, a dark shadow rising from the depths, creeping across vast distances, and preparing to engulf the environment. The torrent – and the seeping blackness – was relentless.

It had started with an explosion. On the evening of 20th April 2010 a succession of failures led to twin blasts that ripped through the engine rooms of Deepwater Horizon, an oil rig located 52 miles off the coast of Venice, Louisiana. Eleven workers were killed, and as the sun rose the next morning to cast light on the troubled structure, no-one could fail to notice its precarious leaning and listing, threatening to topple and sink to the depths. The world held its breath.

Deep beneath the surface, trouble was already brewing. Vast amounts of crude oil was poised, ready to burst forth. Two days later Deepwater Horizon finally fell; a groaning, screeching mass of metal, a giant sinking to its knees and then to the bottom of the Gulf, 1500m below. It was found almost half a mile away from its initial mooring, upside down, a broken wreck marring the seafloor, a herald of the environmental catastrophe to come.

Initial estimates on the oil flow were inaccurate. Suggestions of 1000 barrels of crude oil per day leaking from a deep sea geyser soon became updated with a figure of 5000 barrels per day. A month later, and with accurate estimates still not truly possible, the figure had risen to somewhere between

Attempts to resolve the problem included sophisticated robot repairs and ‘top hat’ containment domes, to decidedly unsophisticated techniques such as blasting old tyres, golf balls, mud and debris at high speed into the mouth of the geysers, in a plugging strategy known as the ‘junk shot’. Everything failed. For weeks the oil continued to spew from the depths, and the surface slick continued its inexorable, damaging spread. Eventually, a wrenching 87 days after the initial deadly explosion, BP announced they’d finally plugged the problem, quite literally, with a mass of concrete. With so much damage already done, the ecosystems of the Gulf of Mexico and its beautiful coasts faced a bumpy road to recovery.

Five years on, the media frenzy has long since faded. The politics and lawsuits revolving around the spill have been ongoing in the intervening years, but without constant headlines and attention, the Deepwater Horizon spill has slipped from the public eye. Many people have forgotten, or are unaware of the problems the Gulf still faces in the aftermath of the event. Many have stopped thinking about it, but there are dedicated teams of scientists that haven’t, and April 2015 saw the publishing of Five Years and Counting: Gulf Wildlife in the Aftermath of the Deepwater Horizon Disaster, a telling report from the National Wildlife Federation (NWF) of the US on how life in the Gulf is faring. As recently as March 2015 BP stepped up the PR effort to insist all was well in the gulf, but evidence is mounting that the environment and once thriving wildlife of the area is struggling to bounce back. Highlighted in the NWF’s comprehensive report, many species are showing signs that hint at long term effects, with the potential for damage to continue to manifest in unexpected ways in years to come.

Image credit: Petty Officer 3rd Class Patrick Kelley / Flickr
Image credit: Petty Officer 3rd Class Patrick Kelley / Flickr

Brown pelicans looking somewhat shell-shocked and coated in dark sludge quickly became an iconic image of the spill, photos that captured the innocence and vulnerability of wildlife unable to cope with the crude deluge. Estimates suggest that oil killed 12% of the entire brown pelican (In the act of cleaning their own feathers of the crude oil coating them, birds can ingest a cocktail of toxins that can kill, or leave survivors with compromised health and reproductive abilities. Indeed, studies of white pelicans (Pelecanus erythrorhynchos) in the years following the Deepwater disaster found oil and the dispersants used to tackle it both present in their eggs. The full effects of the contaminating compounds discovered are currently being investigated, but previous studies suggest that birth defects and disrupted embryo development are very real possibilities. Other birds too have suffered. In the aftermath, laughing gulls (Leucophaeus atricilla) suffered a huge decline. Studies indicated a third of the gull’s population were killed as oil spilled into their ground nesting colonies on the Gulf’s shores. The percentage translates to a staggering 730,000 gulls dead, no longer bringing coastal areas to life with their high-pitched laughter.

Bottlenose dolphins (Tursiops truncatus) have been amongst the hardest hit. A number of charismatic bottlenose pods make the Gulf their home: some are coastal populations, making the most of the rich areas around the Gulf’s bays and estuaries, while other populations remain in deeper, open waters. There is a suggestion that they all may have suffered. Since the spill, bottlenose dolphins have been found dead in record numbers along Gulf shores stretching from Florida to Louisiana. The distribution of these deaths hints at the cause. In areas heavily-hit by oil, such as sites on the Louisiana coast, dolphins were found deceased at four times their historic rates. Surviving dolphins have also been studied to investigate physical effects of polluted Gulf waters. An incredible half of those examined were deemed to be very ill, with unusual masses found in lungs, adrenal issues, and noticeable tooth loss. There appears to be a general picture of ill health amongst bottlenose dolphins of the Gulf, especially when compared to unaffected pods nearby in Florida waters.

Less immediately noticeable than the charismatic birds and mammals, but no less important to the Gulf’s ecosystems are the affected marine species. Well-documented worldwide, coral reefs provide a critical habitat for a myriad of marine life. At a deep-sea site just four miles away from the site of the geyser, 90% of corals in an established colony showed lasting damage from the affects of oil exposure. Two reefs in shallower waters caught in the black, oily embrace also showed elevated damage, and here scientists were able to identify a dramatic decline in fish populations on both reefs. Coral reefs are notoriously slow-growing, and bouncing back from such a hit will not be easy – it could be centuries before the affected corals of the Gulf recover and reach their previous splendour. Corals aren’t the only builders in the Gulf; oysters are abundant in the area’s estuaries, and they too build vital reefs as they settle in layers atop each other, providing habitat, shelter and foraging for life ranging from fish to crabs. As filter feeders – slurping up the surrounding water and taking from it everything they need – oysters can be particularly vulnerable to anything unpleasant and toxic in their environment, and, being oysters, aren’t well equipped at rapidly escaping any dark, contaminated waters. Not surprisingly, compared with pre-disaster numbers, oyster harvests in affected estuaries of Louisiana, Mississippi, and Alabama have been markedly lower in the years since the spill. While there may be other influences on lower hauls, a distinct drop in oyster larvae survival during 2011 and 2012 appears to have been an important factor.

Amongst other species included in the comprehensive collection of reports are Atlantic bluefin tuna, who have been found to suffer heart conditions as a result of a chemicals in the oil; Kemp’s ridley sea turtles, the smallest of the world’s sea turtles suffering a decline in nesting since 2010; acrobat ants, whose colonies play such important roles in the Gulf’s coastal marshes and whose numbers appear to be dwindling in the spill’s aftermath; and seaside sparrows, another resident of the coastal marshes where gallons of crude oil washed ashore, that could be feeling a knock-on effect of struggling coastal insect populations, as the bird’s own prey and food sources are diminished.

There are many more affected species, all touched by the oil in different ways. “We know that impacts vary greatly between species, from reproductive failure to cardiac issues – from direct mortality to gene damage. And the impacts have the potential to have population-level impacts down the road,” says lead author of the report, Ryan Fikes, of the NWF. “We also know that oil remains deep in on our ocean floors, nearshore along Gulf beaches, and buried under coastal marshes; therefore the risk of exposure and additional impacts still lingers after 5 years, and will likely for years to come.”

Image credit: Petty Officer 3rd Class Patrick Kelley / Flickr
Image credit: Petty Officer 3rd Class Patrick Kelley / Flickr

The varied and wonderful wildlife of the Gulf of Mexico were not the only things affected. Human coastal communities too felt the touch of the spill, as the seafood economy of the area took a substantial hit. Shrimp farmers in the coastal marshlands saw their livelihoods disappearing, and crab, oyster and fish populations all suffered. As a result, so did the families and communities that rely on them, be it for income or an important source of protein. Fikes found himself in the middle of the experience: “

Science is not just about identifying and reporting, it is about finding a way to fix things too. Key areas that need focus are the eroded coastal wetlands, haven for so much life, and the decimated oyster reefs that provide such critical habitat and play a role in feeding the human residents of the Gulf coast. “We know that our wildlife depend upon these habitats for food, reproduction, and protection from predators. And we know that our vibrant coastal economy depends on these natural resources for seafood production, for tourism, and for so many of the things that make up our way of life”. For humans, the importance of restoration efforts in the Gulf cannot be understated, suggests Fikes: “Comprehensive restoration of the Gulf’s critical ecosystems is our best bet to safeguard against coastal storms, ensure our way of life, and maintain a thriving coastal economy. The need for restoration is now!”

The five year anniversary of the catastrophe has allowed researchers to propel their recent findings once more into the public eye, and bring to everyone’s attention the fragile state and still uncertain future of the afflicted waters, wildlife, and coastlines. Conservationists are working hard on restoration projects, and scientists are still trying to identify long-term impacts on the Gulf’s wildlife and predict what may happen next. One thing is certain, from the metal carcass of a wrecked rig, rusting on the sea floor, to the bodies of bottlenose dolphins, heartbreakingly found lifeless on the shore, the Deepwater Horizon disaster has left its mark, and its enduring legacy will be fully revealed in years to come.

This article was originally published in the May 2015 issue of Biosphere magazine. Subscribe to it here for the latest research from the natural world and stunning photography:

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