Deepwater Horizon Oil spill: The Environmental Impact
It was a disaster that ended up as one of the worst oil spills in modern history, the Deepwater Horizon didn’t just leak, it gushed. The depth of the well made the spill extremely difficult to repair and it required an incredible engineering feat to solve the problem.
Unfortunately, the problem was not immediately resolved when the leak was stopped. Between 492,000 – 627,000 tonnes of oil were dumped into the ocean, but it wasn’t just oil that was dumped, 500,000 tons of natural gas was also dumped into the Gulf of Mexico offshore waters over during the period of 84 days.
With the seemingly insurmountable cleanup effort, many were probably breathing a sigh of relief over the reports following the disaster that naturally-occurring microbes had consumed much of the gas and oil.
Unfortunately a team of researchers led by marine scientists from the University of Georgia published a paper in the journal Nature Geoscience that not just questions that conclusion, but provides evidence that microbes may not be capable of removing the contaminants as quickly and easily as once believed.
“Most of the gas injected into the Gulf was methane, a potent greenhouse gas that contributes to global climate change, so we were naturally concerned that this potent greenhouse gas could escape into the atmosphere,” said Samantha Joye, senior author of the paper, director of the study and professor of marine science in UGA’s Franklin College of Arts and Sciences. “Many assumed that methane-oxidizing microbes would simply consume the methane efficiently, but our data suggests that this isn’t what happened.”
Professor Joye, along with other universities and government organizations measured methane concentrations and activity of methane-consuming bacteria for roughly ten months. Luckily the researchers had taken samples in March 2010, or prior to the blowout, which turned out to be invaluable.
The amount of methane released into the water during the leak allowed the bacteria that feed on the gas to flourish for the first two months, but their numbers dropped abruptly despite the fact the methane was still being released from the well.
This new study suggests that the sudden drop in bacteria was not because of an absence of methane, but due to environmental, physiological, and physical constraints that made it difficult or even impossible for bacteria to consume methane effectively.
“For these bacteria to work efficiently, they need unlimited access to nutrients like inorganic nitrogen and trace metals, but they also need elevated methane levels to persist long enough to support high rates of consumption,” Joye said. “The bacteria in the Gulf were probably able to consume about half of the methane released, but we hypothesize that an absence of essential nutrients and the dispersal of gas throughout the water column prevented complete consumption of the discharged methane.”
Despite the conclusion from the group, Joye insists that there is no serious conflict between their analyses and other studies. The issue she says is the time of sampling done, the other studies were sampling on a short-term timeline. “I hope our paper clearly relays the message that long-term sampling is the only way to capture the evolution of a natural system as it responds to large perturbations like oil well blowouts or any other abrupt methane release,” she said.
No matter how you slice it, the lasting impact this disaster had on the gulf region is sure to be felt much longer than the 84 days that it was actively leaking. It is unfortunate to think that the methane discharged [a very potent greenhouse gas] most likely was not contained the way that the initial reports suggested.
There were a lot of lessons learned the hard way because of the Deepwater Horizon. Let’s just hope that those lessons are actually used to change the way things are done, if not for the human race, then for the bad press that follows these tragedies.
Depressing, no? Well if you want more information you can find the full study —here!
So how about you guys, how do you feel about all this?
Crespo-Medina M., Meile C.D., Hunter K.S., Diercks A.R., Asper V.L., Orphan V.J., Tavormina P.L., Nigro L.M., Battles J.J. & Chanton J.P. & (2014). The rise and fall of methanotrophy following a deepwater oil-well blowout, Nature Geoscience, DOI: 10.1038/ngeo2156