Oil Eaters: How Nature Cleans Up the Deepwater Horizon Spill

Experts have found that certain parts of the ocean may be more resistant to the adverse effects of oil spills than was previously thought. That's largely thanks to some naturally present oil eating-bacteria that inhabit certain bodies of water, such as the Gulf of Mexico. However, these organisms may be missing some key toxins, leaving humans to clean up a near-invisible mess.

The 2010 Deepwater Horizon disaster released nearly 210 million gallons of oil into the Gulf of Mexico, wreaking havoc on the region's ecosystems. However, past research had found that the Gulf had recovered relatively quickly, compared to past spills.

It was initially reported that this was largely thanks to a strong and practiced emergency response, in which the spill was quickly contained and clean-up efforts were launched in a timely and efficient fashion. However, now researchers are arguing that the Gulf's speedy recovery was in-part thanks to its natural microbial populations, who have been feeding on oil in the region for countless centuries.

Oil Eaters to the Rescue

According to a study of the Deepwater Horizon aftermath published in the journal Environmental Science and Technology, the Gulf of Mexico was already home to countless unidentified microorganisms that appear to consume and break down crude oil, even before the spill.

These organisms reportedly fed off natural oil seeps from rock underlying the Gulf - seeps that release the equivalent of an estimated 560,000-1.4 million barrels of oil annually.

"The Deepwater Horizon oil provided a new source of nutrients in the deepest waters," study author Terry Hazen explained in a statement. "With more food present in the water, there was a population explosion among those bacteria already adapted to using oil as a food source. It was surprising how fast they consumed the oil. In some locations, it took only one day for them to reduce a gallon of oil to a half gallon. In others, the half-life for a given quantity of spilled oil was six days. This data suggests that a great potential for intrinsic bioremediation of oil plumes exists in the deep sea and other environs in the Gulf of Mexico."

Hazen added that the "bottom line" of this study is that the Gulf and regions like it are home to organisms more than capable of mitigating a spill.

"It shows that we may not need the kinds of heroic measures proposed after the Deepwater Horizon spill, like adding nutrients to speed up the growth of bacteria that breakdown oil, or using genetically engineered bacteria," he said. "The Gulf has a broad base of natural bacteria, and they respond to the presence of oil by multiplying quite rapidly."

Hazen's work was first presented at the 245th National Meeting & Exposition of the American Chemical Society (ACS) in 2013. However, a newer study conducted by Olivia Mason suggests that things aren't as rosy for the Gulf as Hazen's work suggested.

The Problem With Picky Eaters

Nature World News previously reported how vulnerable coral communities in the Gulf are still being impacted by the aftermath of the spill.

Now, Mason has recently published a paper in the journal Frontiers in Microbiology that claims that a species of Colwellia bacteria - identified as a primary oil eater - does not chow down on a very dangerous toxin in the oil, leaving it to settle on the seafloor.

Hazen's report did not identify specific species of oil-eaters, as very few are known. However, according to Mason's report, it is very likely that Colwellia is one, if not the main, of the Gulf's oil-eating bacteria.

Studying Colwellia in deep sea plumes, the researchers found that the bacteria munched on gaseous hydrocarbons, benzene, toluene, ethylbenzene and xylene compounds - all major contaminants of an oil spill.

However, these picky eaters appeared to avoid contaminants called polycyclic aromatic hydrocarbons (PAHs).

"Those PAHs could persist for a long time, particularly if they are buried in the ocean floor where lack of oxygen would slow PAH degradation by microorganisms," Mason said in statement. "They're going to persist in the environment and have deleterious effects on whatever is living in the sediment."

A Helping Hand

And that's a problem, as PAHs are suspected carcinogens. So what can be done? According to the authors of this study, while nature can take care of a spill in its own way, human intervention is still necessary and even expected.

The US Environmental Protection Agency (EPA) explains that in the wake of an oil spill, its first and most pressing concern is containing the spill. These efforts mainly consist of introducing barriers and absorbents (like clay, straw, and even ground corncobs) to gather the black sludge so iconic for a spill all in one place. The EPA and other agencies also often take up "scare tactics," using sounds and smells to keep wild animals away from the quarantined spill.

Earlier this year Nature World News reported about a new oil-repellant meshing that could conceivably make this first essential stage much less time-consuming.

Researchers note that this is the most vulnerable time for the affected ecosystem, when helpful microbial life has not yet boomed in population size. However, with containment efforts being a priority, little is usually done in terms of damage mitigation within the first 24 hours.

That's why researchers recently intentionally released oil into a small contained portion of the North Sea, in order to better understand what can be done during this early exposure.

Once the spill is finally contained, experts can attempt to address the spill directly. The EPA reports using some chemical agents to disperse the oil. Biological agents have been proposed in the past as well, with even genetically modified bacteria being discussed as a possible agent in the past.

The recent discovery of microorganisms that live in oil may help make this final important stage of the cleanup more natural.

"We found complex microbial communities, which play an active part in oil degradation," author Rainer Meckenstock said in a recent release.

He hopes to one day see these organisms helping in oil spill cleanups, potentially working hand-in-hand with the ocean's more picky eaters.

A study detailing this latest find was published in the journal Science on August 8.