SCIENTIST SAYS DEEPWATER HORIZON OIL LOCATED

FROM:  NATIONAL SCIENCE FOUNDATION 

Where did the Deepwater Horizon oil go? To Davy Jones' Locker at the bottom of the sea

New analysis traces oil to its resting place on the Gulf of Mexico sea floor
Where's the remaining oil from the 2010 Deepwater Horizon disaster in the Gulf of Mexico?

The location of 2 million barrels of oil thought to be trapped in the deep ocean has remained a mystery. Until now.

Scientist David Valentine of the University of California, Santa Barbara (UCSB) and colleagues from the Woods Hole Oceanographic Institution (WHOI) and the University of California, Irvine, have discovered the path the oil followed to its resting place on the Gulf of Mexico sea floor.

The findings appear today in the journal Proceedings of the National Academy of Sciences.

"This analysis provides us with, for the first time, some closure on the question, 'Where did the oil go and how did it get there?'" said Don Rice, program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research along with NSF's Division of Earth Sciences.

"It also alerts us that this knowledge remains largely provisional until we can fully account for the remaining 70 percent."

For the study, the scientists used data from the Natural Resource Damage Assessment conducted by the National Oceanic and Atmospheric Administration.

The U.S. government estimates the Macondo Well's total discharge--from April until the well was capped in July--at 5 million barrels.

By analyzing data from more than 3,000 samples collected at 534 locations over 12 expeditions, the researchers identified a 1,250-square-mile patch of the sea floor on which four to 31 percent of the oil trapped in the deep ocean was deposited. That's the equivalent of 2 to 16 percent of the total oil discharged during the accident.

The fallout of oil created thin deposits that are most extensive to the southwest of the Macondo Well. The oil is concentrated in the top half-inch of the sea floor and is patchily distributed.

The investigation focused primarily on hopane, a nonreactive hydrocarbon that served as a proxy for the discharged oil.

The researchers analyzed the distribution of hopane in the northern Gulf of Mexico and found that it was concentrated in a thin layer at the sea floor within 25 miles of the ruptured well, clearly implicating Deepwater Horizon as the source.

"Based on the evidence, our findings suggest that these deposits are from Macondo oil that was first suspended in the deep ocean, then settled to the sea floor without ever reaching the ocean surface," said Valentine, a biogeochemist at UCSB.

"The pattern is like a shadow of the tiny oil droplets that were initially trapped at ocean depths around 3,500 feet and pushed around by the deep currents.

"Some combination of chemistry, biology and physics ultimately caused those droplets to rain down another 1,000 feet to rest on the sea floor."

Valentine and colleagues were able to identify hotspots of oil fallout in close proximity to damaged deep-sea corals.

According to the researchers, the data support the previously disputed finding that these corals were damaged by the Deepwater Horizon spill.

"The evidence is becoming clear that oily particles were raining down around these deep sea corals, which provides a compelling explanation for the injury they suffered," said Valentine.

"The pattern of contamination we observe is fully consistent with the Deepwater Horizon event but not with natural seeps--the suggested alternative."

While the study examined a specified area, the scientists argue that that the observed oil represents a minimum value. They believe that oil deposition likely occurred outside the study area but so far has largely evaded detection because of its patchiness.

"These findings," said Valentine, "should be useful for assessing the damage caused by the Deepwater Horizon spill, as well as planning future studies to further define the extent and nature of the contamination.

"Our work can also help assess the fate of reactive hydrocarbons, test models of oil's behavior in the ocean, and plan for future spills."

Co-authors of the paper are G. Burch Fisher and Sarah C. Bagby of UCSB; Robert K. Nelson, Christopher M. Reddy and Sean P. Sylva of WHOI and Mary A. Woo of University of California, Irvine.

-NSF-

NANOGRID TECHNOLOGY MAY BE USEFUL IN BREAKING DOWN WATER POLLUTANTS

FROM:  NATIONAL SCIENCE FOUNDATION 
Nanogrid, activated by sunlight, breaks down pollutants in water, leaving biodegradable compounds
November 8, 2013

Oil spills do untold damage to the environment--to the waters they pollute and to marine and other wildlife. The Deepwater Horizon spill in the Gulf of Mexico in 2010, for example, the largest accidental marine oil spill in the history of the petroleum industry, flowed unabated for three months.

Typically, such oil spills are extraordinarily difficult to clean up.

Soon, however, the process may become infinitely easier and ecologically friendly, the result of a new invention by a National Science Foundation- (NSF) supported scientist.

Pelagia-Irene (Perena) Gouma, a professor in the Department of Materials Science and Engineering at the State University of New York (SUNY) Stony Brook, created a novel "nanogrid," a large net consisting of metal grids made of a copper tungsten oxide, that, when activated by sunlight, can break down oil from a spill, leaving only biodegradable compounds behind.

"We have made a new catalyst that can break down hydrocarbons in water, and it does not contaminate the water," says Gouma, who also directs SUNY's Center for Nanomaterials and Sensor Development. "It utilizes the whole solar spectrum and can work in water for a long time, which no existing photocatalyst can do now. Ours is a unique technology. When you shine light on these grids, they begin to work and can be used over and over again.

"Something like this would work fine for any oil spill," Gouma adds. "Any ship can carry them, so if they have even a small amount of spill, they can take care of it."

Initially, the grids, which resemble non-woven mats of miniaturized ceramic fishing nets, probably will be used for oil spills, although they potentially could prove valuable in other applications, such as cleaning contaminated water produced by "fracking," the process of hydraulic fracturing to extract natural gas from shale, and as well as from other industrial processes.

"Fracking is a reality," she says. "It is happening. If the science and engineering we produce in the lab can help alleviate environmental problems, we will be happy about that."

Because they work well both in water and air, they also could be a chemical-free, possibly even water-free, method of cleaning clothes in the future. "The dry cleaning process that we now use involves a lot of contaminants that have to be remediated and treated, such as benzene," she says. "This could be a dry cleaning substitute that would be more environmentally friendly than current dry cleaning approaches."

Moreover, "imagine you lay this over your clothes, and expose them to light. You won't need a washing machine, or chemicals, or even water," she adds.

The photocatalytic nanogrids™ invented in her lab are made by a unique self-assembly process that occurs "during the nanomanufacturing on non-woven nanofibrous mats deposited on metal meshes," according to Gouma. "Upon heating, metal clusters diffuse inside polymeric nanofibers, then turn into single crystal nanowires, then oxidize to form metal oxide--ceramic--nanoparticles that are interconnected, like links in a chain," she says.

These form an unusual and "robust third architecture that allows for the highest surface area, providing maximum exposure to the contaminant to be remediated, while the nanoscale particle sizes enable fast catalytic action," she adds. "The result is a self-supported water remediation targeted photocatalytic technology that has no precedent."

In the fall of 2011, Gouma was the first scientist to receive a $50,000 NSF Innovation Corps (I-Corps) award, which supports a set of activities and programs that prepare scientists and engineers to extend their focus beyond the laboratory into the commercial world.

Such results may be translated through I-Corps into technologies with near-term benefits for the economy and society. It is a public-private partnership program that teaches grantees to identify valuable product opportunities that can emerge from academic research, and offers entrepreneurship training to faculty and student participants.

"The I-Corps program was very useful for the students," she says. "It got them involved, and got them to realize that there is a practical application to what they do. It was extremely useful for them to see how something developed in the lab could be used in the field, and that you actually can start a business from something started in the lab."

She and her team are in the process of creating a startup business--they have two patents pending on the process--with the hope of scaling up production and carrying out pilot studies.

"We want to demonstrate feasibility in the real world, and then produce them in large quantities," she says. "We have proof of principle that our technology can be useful. Our technique works in the lab. We now need to make sure that it works in the field."

-- Marlene Cimons, National Science Foundation
Investigators
Jusang Lee
Clive Clayton
Pelagia Gouma

DEEPWATER HORIZON OIL SHEEN SOURCE IDENTIFIED

Oil Sheen.  Credit:  NOAA

FROM: NATIONAL SCIENCE FOUNDATION

Study Identifies Source of Oil Sheens Near Deepwater Horizon Site

A chemical analysis indicates that the source of oil sheens recently found floating at the ocean's surface near the site of the Gulf of Mexico Deepwater Horizon oil spill is pockets of oil trapped within the wreckage of the sunken rig.


First reported to the U.S. Coast Guard by multinational oil and gas company BP in September 2012, the oil sheens raised public concern that the Macondo well, which was capped in July 2010, might be leaking.

However, both the Macondo well and the natural oil seeps common to the Gulf of Mexico were confidently ruled out, according to researchers from the University of California Santa Barbara (UCSB) and the Woods Hole Oceanographic Institution (WHOI).

The results are published this week in the journal Environmental Science & Technology.

"Silver linings in the dark cloud of the Deepwater Horizon spill are very hard to come by," says Don Rice, program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research.

"Among the precious few are the lessons we've learned about the marine biogeochemistry of petroleum mixtures. This team has demonstrated convincingly that we can also use what we have learned for forensic purposes."

The researchers used a recently patented method to fingerprint the chemical makeup of the oil sheens, and to estimate the location of the source based on the extent to which gasoline-like compounds evaporated from the sheens.

"The results demonstrate a recently developed geochemical analytical method and may have real-world implications in environmental management strategies for future contamination incidents," says Deborah Aruguete, program director in NSF's Division of Earth Sciences, which co-funded the research.

Because every oil sample contains chemical clues pointing to the reservoir it came from, scientists can compare it to other samples to determine if they share a common source.

"This appears to be a slow leak from the wreckage of the rig, not another catastrophic discharge from a deep oil reservoir," says geochemist David Valentine of UCSB.

"Continued oil discharge to the Gulf of Mexico from the wreckage of the Deepwater Horizon rig is not a good thing, but there is some comfort that the amount of leakage is limited to the pockets of oil trapped within the wreckage of the rig."

Valentine and WHOI's Chris Reddy have worked on Deepwater Horizon for much of the last three years, investigating a wide range of problems, including the composition of the oil, detection of subsurface plumes, the biodegradation of the oil, the fate of the dispersants and the chemical transition from floating oil slicks to sunken tar balls.

"Because of our ongoing funding from NSF, we were prepared to interrogate the source of mysterious oil sheens in the Gulf of Mexico," said Valentine.

"We've been exploring new ways to do this for several years in the context of natural seeps, and this event provided us an opportunity to apply our fundamental advances to a real-world problem."

The scientists analyzed 14 sheen samples skimmed from the sea surface during two trips to the Gulf of Mexico.

Using comprehensive two-dimensional gas chromatography, a technique developed in Reddy's lab, the researchers first confirmed that the sheens contained oil from the Macondo well.

But the sheen samples also contained trace amounts of olefins, industrial chemicals used in drilling operations. The presence of olefins provided a fingerprint for the sheens the scientists could compare to the samples they had analyzed during the last three years.

Olefins are not found in crude oil and their uniform distribution in the sheens indicated that the Macondo well was unlikely to be the source.

The team surmised that the sheens must be coming from equipment exposed to olefins during drilling operations.

"The occurrence of these man-made olefins in all our sheen samples points to a single main source, which contains both Macondo oil and lesser amounts of the drilling fluids that harbor the olefins," said Valentine.

"This pointed us to the wreckage of the rig, which was known to have both, as the most likely source for the sheens."

The researchers compared the sheen samples to other field samples, some of which they expected would contain olefins and some they thought would not.

The reference samples included two pieces of debris from the Deepwater Horizon found floating in May 2010, as well as oil collected by BP in October 2012, during an inspection of the 80-ton cofferdam that had been abandoned at the seafloor after its use in a failed attempt to cover the Macondo well in 2010.

The team's gas chromatography analysis of BP's cofferdam samples definitively showed that it was not the sole source of the leak as there were no olefins present.

Prior to the analysis the cofferdam had become the prime suspect as the source when BP found small amounts of oil leaking from its top.

BP scientists acquired oil samples from this leak point before sealing the leak, thinking they had resolved the problem. However, the sheens on the sea surface persisted, and the lack of olefins pointed to another source entirely.

When Valentine and Reddy compared the chemical makeup of the sheens with debris found floating in 2010, they found a match. That debris, which came from the rig itself, was coated with oil and was contaminated by drilling mud olefins.

"The ability to fingerprint synthetic hydrocarbons allowed us to crack this case," Valentine said. "We were able to exclude a number of suspects and match the olefin fingerprint in the new oil slicks to that of the wreckage from the sunken rig."

The chemical analysis also told researchers which sheens had surfaced more recently than others, allowing them to reconstruct a trajectory for local ocean currents that pointed back to the oil's source.

By looking for sheens that showed the least amount of evaporation, they determined that oil surfaced closer to Deepwater Horizon wreckage than to the cofferdam site.

To explain how the oil might be trapped and released from the wreckage, the scientists point out that when the Deepwater Horizon rig sank, it was holding tanks containing hundreds of barrels of a mixture of drilling mud and oil.

Over time, corrosive seawater can create small holes through which oil can slowly escape to the surface. The researchers suspect that the containers on the rig holding trapped oil may be the source of the recent oil sheen.

In addition to Valentine and Reddy, the research team consisted of Christoph Aeppli and Robert Nelson of WHOI, and Matthias Kellermann of UCSB.

The Gulf of Mexico Research Initiative, Woods Hole Oceanographic Institution and a Swiss National Science Foundation Postdoctoral Fellowship also funded the research.

-NSF-