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Who ate the Oil from the Deepwater Horizon Spill?

Posted on July 3rd, 2017 by in New Materials & Applications

burning oil

Aerial View of the Deepwater Horizon Drilling Rig after the Accident (Source: http://media.salon.com)

In the summer of 1976 I worked for an oil company on the Island of Lavan in the Persian Gulf.  The island was a logistics and command base for the offshore drilling rigs.  We flew in and out of the island on a Boeing 737-100 using a short airstrip and then took helicopters to fly to the drilling rigs. 
I spent plenty of time over water and saw the after effects of oil leaks.  There were rainbow color striations of oil floating on the water, which worried me about the pollution of the shimmering blue/green waters of the Persian Gulf.  It turns out those were the halcyon days of pristine open seas.  In the last forty plus years there have been monumental oil spills, some comparable to the 1910 Lakeview Gusher during which 9 million barrels of oil was released in Kern County, California.

Oil Spills

The rush to drill in the deep seas has resulted in oil companies taking unwarranted risks that have lead to large oil spills and natural gas releases (Figure 1).  The main victims are the environment, the wildlife, beaches, seaside communities, fishermen and others.  Part of the spillage remains in the seawater either floating or sinking below the surface.  Neither of those victims is an influential constituency or well represented in the centers of power. The fish and foul die quietly, notwithstanding the few advocates who raise their plights while attempting to rescue as many as possible.

oil spills map

Figure 1 Map of the eleven of the world’s largest oil spills (Source: http://Geology.com)

Except for the governments no association has a chance to ever match the power of petroleum constituencies in the halls of power.  Disregarding of any other differences among them, governments of oil producing countries, whether dictatorships such as Saudi Arabia, Brunei, or Congo; or democracies like UK or Norway, are all unified in their support of oil industries.  In the face of accidents powerful oil lobbies go to work on damage control and call for interminable studies of the damages.

In the end after offering compensation for the damages, the oil industry waits out the bad publicity to be replaced by the next news de jour.  BP Corp’s behavior after the Deepwater Horizon disaster is typical of the bait and switch tactics of the violators.  Instead of focusing on healing the real destruction it caused, BP was in the courts to save money.  BP took its lawsuit, aiming to stop making settlement payments, all the way to the United States Supreme Court only to be told by the Justices to continue to pay what they had already committed to.  All the while the sticky tar was killing fish and fowl, destroying the ecosystems and beaches of the Gulf of Mexico (Figure 2), and ruining the seafood and tourism industries of Texas, Louisiana, Mississippi, Alabama, and Florida.

Oil spill

Figure 2 Deepwater Horizon Oil Spill on the Beaches of Gulf of Mexico (Source: http://www.loe.org original credit: http://bigstockphoto.com)

The largest oil spill ever occurred in the Persian Gulf in 1991.  It was deliberate, becoming one of the largest man-made disasters in history.  Saddam Hussein’s Iraqi forces invaded Kuwait during the first Persian Gulf War.  While the Coalition forces were driving them out they opened pipeline valves at the Sea Island Oil Terminal in Kuwait causing oil to release onto the ground and spilled the cargos of tankers into the Persian Gulf. During their retreat they set the wells and pipeline terminals on fire.  It is impossible to determine the actual volume of oil spilled, but the estimates indicate the total could be 11,000,000 barrels.

Who ate the Spilled Oil?

In 2010 the Deepwater Horizon drilling rig released an estimated 4.2 million barrels of oil into the Gulf of Mexico – the largest offshore spill in US history (Source: Business Insider, N. Dombrowski, B. J. Baker, June 26, 2016).  Later on after recovery operations had been completed experts attempted to account for the fate of most of the oil that was left in the Gulf waters.  This was an important question, because it was unclear how much of the released oil would break down naturally and quickly.  If the oil sank to the ocean floor, scientists expected that it would cause more extensive harm to the environment.  Before the Deepwater Horizon spill, scientists had observed that marine bacteria were very efficient at removing oil from seawater.

The Deepwater Horizon oil spill has become one of the most studied spills in history.  There has been confirmation of the fact that microbes have been eating the oil.  The exact role of the microorganisms has been a subject on which the scientists have not agreed.  A number of research teams have focused on the microbes’ mechanisms of chewing up the numerous components of the released crude oil.  Professor Terry Hazen (now at the University of Tennessee) led one of the early works on the Deepwater Horizon oil spill at Berkeley Lab.  The study provided the first data ever on the microbial activity from a Deepwater dispersed oil plume.  The latest study led by Dr. Gary Anderson, also at the Berkeley Lab, has identified: 1. The mechanisms the bacteria have used to degrade the oil and 2. The relationship of these organisms involved in the spill to previously characterized hydrocarbon-degrading organisms (Source: Early Edition, Proceed of the National Acad. of Sci., www.pnas.org/cgi/doi/10.1073/pnas.1703424114, May 30, 2017).

Dr. Andersen notes that it is not clear if the degradation of oil at these depths would have occurred in other offshore oil-producing regions. “The Gulf of Mexico is home to one of the largest concentrations of underwater hydrocarbon seeps, and it has been speculated that this helped in the selection of oil-degrading microbes that were observed in the underwater plumes,” he said (Source: Science Daily, www.ScienceDaily.com, June 26, 2017).

In another study scientists used DNA analysis to confirm that certain kinds of marine bacteria efficiently broke down some of the major chemical components of oil from the spill. They also identified the major genetic pathways these bacteria used for this process, and other genes, which they likely need to thrive in the Gulf.  Altogether, the results suggest that some bacteria can not only tolerate but also break up oil, thereby helping in the cleanup process (Reconstructing metabolic pathways of hydrocarbon-degrading bacteria from the Deepwater Horizon oil spill, N. Dombrowski, J. A. Donaho, T. Gutierrez, K. W. Seitz, A. P. Teske & B. J. Baker, www.nature.com, May 9, 2016).

Observations in the Gulf appeared to confirm that microbes broke down a large fraction of the oil released from BP’s damaged well. Before the spill, waters in the Gulf of Mexico contained a highly diverse range of bacteria from several different phyla , or large biological families. Immediately after the spill, these bacterial species became less diverse and one phylum increased substantially in numbers. This indicated that many bacteria were sensitive to high doses of oil, but a few types were able to persist. By understanding how to support these natural occurring microbes, there is opportunity to better manage the aftermath of oil spills.

Future

New wells being drilled are even deeper than the old ones thus more risky.  Oil exploration offshore of Brazil, Uruguay, and India has now exceeded 3.2 km (2 miles) below the ocean surface. Even though we know the nature has a way of coping with monumental oil spills in the oceans, LET’S BE CAREFUL AND AVOID FUTURE SPILLS BECAUSE THE TOLL ON MAN AND THE NATURE IS SIMPLY TOO HIGH.


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