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Reports of a new oil sheen first surfaced on Aug. 18, close to the site of last year’s devastating spill. BP and Coast Guard officials deployed two submersible vehicles to the site, but BP said a visual inspection indicated there was no oil released from the Macondo well. The Coast Guard said last week that the oil was the result of natural seeps and/or permitted releases at other oil drilling sites, according to the Press-Register newspaper in Mobile, Ala.

Reporters from the Press-Register took some samples of their own and sent them to Louisiana State University, where scientists confirmed the oil was Louisiana sweet crude. It was chemically similar to the oil from the Macondo well, but remains unclear whether that is the source, according to the newspaper’s account.

Volunteers with the Gulf Restoration Network and a group called On Wings of Care have been taking aerial photos since Aug. 19, finding a variety of oil slicks in several spots in the Gulf. Bonny Schumaker, founder of On Wings of Care, said the group has posted several flight logs with dozens of pictures of the sheens. Check it out here.

Natural seeps have occurred in the Gulf of Mexico for millennia, so it’s certainly possible that they are causing these new sheens. But several scientists said their location — right near the Macondo well — is intriguing.

There are a few explanations beyond natural seeps, including the possibility that oil has been leaking from the broken riser pipe that connected the Deepwater Horizon to the well. Neither the pipe nor the well has been salvaged, the Press-Register points out. Or, heavier hydrocarbon constituents could have settled on the bottom during the spill, and as bacteria have broken them down, lighter-density hydrocarbons are now slowly making their way to the surface. The most troubling possibility, the newspaper says, is that the oil is leaking out of the ground beneath the capped wellhead.

As we wait for more answers, let’s hope that is not the case.

[via UPI]

Advanced ocean science tech helps researchers study the spill

The night of June 21, 2010, Reddy and colleagues from the Woods Hole Oceanographic Institution were whisked off their research vessel Endeavor to collect samples directly from the blown Macondo well, which had been spewing oil and natural gas into the Gulf of Mexico for two months. They had 12 hours to do something that had never been done before: Use a robot arm to stick a special bottle directly into the hot hydrocarbons. Now, a year later, their analysis explains just what came out of the well, and sheds more light on what happened to it.

It turns out that certain chemicals in the well behave differently under high pressure than they do at the surface. This explains why some chemicals, but not others, made their way into the huge 22-mile plume of oil that Reddy et. al uncovered last summer. It also explains why some scientific papers examining the spill have seemed to contradict each other, according to Don Rice, director of the National Science Foundation’s chemical oceanography program.

“We now have a far better understanding of how and why an oil ‘spill’ into the ocean from below differs from one from above. The significance of this work extends well beyond the Gulf of Mexico,” he said in a statement.

One of the most confounding problems with the oil spill was scientific uncertainty — about how much oil was leaking into the Gulf, and about what exactly it was, both of which would explain where the oil would go. Reddy and colleagues needed to go directly to the source — the gusher at 5,000 feet below the surface — to see the compounds and therefore understand what would happen to the plume. This sample is called an “end member,” Reddy explained in an interview. A significant fraction of the gusher consisted of hot gas, mainly methane, so this proved a difficult task.

“If you tried to lower a traditional tool into that boiling cauldron and then close it and bring it up to the surface, that bottle would explode. A tiny methane bubble at 5,000 feet becomes a giant methane bubble at atmospheric pressure,” Reddy said.

The research team turned to Woods Hole geochemist Jeff Seewald, who developed a tool called an isobaric gas-tight sampler. It’s intended for collecting fluids from deep-sea hydrothermal vents. They used an oil industry ROV to place the IGT sampler directly over the broken riser pipe, and they collected the only undiluted, non-degraded sample from the spill.

The team found a gas-to-oil ratio of 1,600 cubic feet of gas per barrel of oil, according to a paper on the findings published this week in the Proceedings of the National Academy of Sciences and funded by the NSF. Based on this ratio, and using the federal government’s estimate of 4.1 million barrels of oil, Reddy et. al estimate 1.7 × 1011 g of methane, ethane and propane leaked into the Gulf. That’s about 105 tons. That’s a lot of methane.

But perhaps more interesting is the makeup of the plume, which mostly comprised benzene, toluene, ethybenzene, and total xylenes, or BTEX. BTEX compounds only represented about 2 percent of the oil that came out of the well, but almost 100 percent of the deep-sea plume. They apparently took a right-hand turn 3,000 feet below sea level, whereas the other hydrocarbons — like methane — degraded, washed on shore, were eaten by bacteria, or were burned in the fires that Reddy experienced while gathering his sample.

Studying the plume also required a bit of technical wizardry, Reddy said. WHOI researcher Richard Camilli built a super-sensitive mass spectrometer, which can instantly identify minute quantities of petroleum and other chemical compounds. This tool was used in the initial plume studies last summer, and it helped researchers quantify how the plume and the wellhead gusher were different.

“It shows some of these compounds are likely to evaporate quicker, at shallower depths. Oil is made up of many compounds, and they all have different chemical and physical properties. This work highlights that. Those properties determine what chemicals went into the plume,” Reddy said.

On the surface, this is all different — BTEX compounds quickly volatilize and evaporate into the atmosphere.

“In the case of the Deepwater Horizon oil spill, however, gas and oil experienced a significant residence time in the water column with no opportunity for the release of volatile species to the atmosphere,” the researchers write in the PNAS paper. “Hence, water-soluble petroleum compounds dissolved into the water column to a much greater extent than is typically observed for surface spills.”

The good news is that BTEX is not toxic to marine organisms until it reaches much higher levels than the researchers found in the Gulf. But neurological impairments can occur at lower concentrations, according to the National Science Foundation. It remains to be seen how the persistent BTEX may have affected sea life.

Meanwhile, Reddy and his colleages are still collecting samples from the beaches lining the Gulf Coast. He praised the National Science Foundation for funding ongoing oil spill research programs, which proved useful in the Deepwater Horizon crisis.

“We will continue to hunt and look for remnants of this oil for as long as we can be funded,” he said. “There’s a lot to be learned, about what compounds resist degradation from nature. It sheds tremendous light on this field.”

What could possibly go wrong?

Last month, BP and Russian state-owned energy company Rosneft signed an Arctic exploration deal to develop prospective offshore oil reserves in what is arguably the most hostile drilling environment in the world. The Arctic has long been thought to harbor vast reserves--the US Geological Survey thinks one-fifth of the world’s undiscovered, recoverable supplies are tucked away there. But tapping it is difficult, and the prospect of a spill there somewhat horrifying.

First, the Arctic is a perilous place to drill. Icebergs, gale-force winds, icy temperatures, dense fog--all of these things add up to a potential mine field for drilling operations. All this is compounded by the fact that the Arctic is plunged into darkness for half of the year (just imagine trying to coordinate a Gulf-style cleanup effort in the dark). Ice cover during eight months of the year could block relief ships in case of a disaster, like a blowout or a rig fire.

The Arctic ecosystem is already so fragile, its food chain so delicate, that an unchecked gusher would spell disaster. Which brings us back to Putin, BP, and the hunt for riches in the waters north of Russia’s long Arctic coastline. Russia likes BP because, by Putin’s reasoning, the company has experience with disaster and a serious interest in not repeating its mistakes. It’s unclear if BP having recent experience with ecological disaster means that Russia is expecting to need that kind of experience on hand.

In any case Russia and BP are pressing on, and now that the genie is out of the bottle other Western companies are itching for their shot at Arctic riches. Those include Shell, who recently postponed plans to drill off Alaska’s Arctic coast after some U.S. lawmakers and regulators introduced obstacles to the drilling. We’d be surprised to see similar local opposition to a Parliament- and Putin-approved plan in the Russian Arctic.

[NYT]

Within four months of the oil spill, bacterial blooms had removed more than 200,000 metric tons of dissolved methane, returning concentrations to normal background levels.

That was a surprise, because in mid-June, scientists found methane concentrations nearly 100,000 times above normal levels, and learned it was decomposing slowly, suggesting it would take years for the hydrocarbon to dissipate.

“We couldn’t have been more wrong. It decomposed rather quickly and was completely consumed within a matter of months,” said lead researcher John Kessler, an oceanographer at Texas A&M University, in a news release.

Kessler and colleagues took three cruises aboard the NOAA ship Pisces between Aug. 18 and Oct. 4, collecting 207 separate water samples and measuring their oxygen and methane concentrations. Oxygen drops when bacteria breathe methane, so the researchers say the depleted oxygen levels can only be explained by consumption of the methane.

They also examined the genetic sequences of bacteria in the samples, which suggested a growing population of methane-munching life forms.

Methane, the primary ingredient in natural gas, was to blame for the spill in the first place — on April 20, a methane bubble surged from the Macondo well up the Deepwater Horizon’s drill column, busting several seals as it belched toward the rig. The resulting explosion killed 11 workers and severed the rig from the well, allowing oil to spew forth for 83 days.

As workers attempted to burn, vacuum, sponge and contain the oil, invisible microbial communities were hard at work. Scientists said last August that a previously undiscovered species of bacteria had made quick work of a massive oil plume; apparently methanotrophs, species of methane-munching bacteria, were also feasting on the spill.

Bacteria have evolved to live with the Gulf’s naturally occurring oil seeps and high methane concentrations, so it makes sense that they were ready to go to work. Apparently they are more effective than we thought.

As with any controversial study, not everyone was satisfied with the results — Ian MacDonald, a professor of biological oceanography at Florida State University, told NPR the team did not account for deep-sea currents that could have carried away the methane. Further studies will shed more light on the findings.

[Science]

Secretary of Energy Steven Chu and Secretary of the Interior Ken Salazar have officially declared that the cement cap permanently plugging BP’s Macondo well is successfully in place, ending a five-month effort that nonetheless saw nearly 4.9 million barrels of oil escape into the Gulf of Mexico. "With the successful first intercept by the relief well and our confirmation through pressure tests that the cement plugs are secure, we can now declare BP's Macondo well effectively dead,” the secretaries said in a joint statement. Finally.

[DOE]

Samantha Joye, a professor in the Department of Marine Sciences at the University of Georgia, set sail August 21 on the research vessel Oceanus and has been posting blog updates throughout the mission. Over the weekend, she wrote that her team found a layer of oil in a valley on the seafloor, about 18 miles from the wellhead. It is two inches thick in some spots, and it rests on top of recently dead sea creatures like shrimp and tubeworms.

Joye expected to find some oil on the seafloor, she told the AP — just not that much. Her team is the second in as many months to announce finding oil at the bottom; last month, a University of South Florida crew reported finding oil droplets 1.4 miles beneath the surface.

The presence of seafloor oil is another blow to the theory that most of the spilled oil disappeared. Scientists previously said plenty of oil was floating in an invisible plume, and while yet another research team said microbes were eating it, not all of it could be accounted for. Several experts, including some government scientists, believe at least some of the oil sank to the bottom, and that’s what Joye’s research seems to prove.

Although she can’t be certain until they conduct further tests this week, the oil almost certainly came from the spill and not a natural seep, Joye said. It clearly came from above the seafloor, not below, she says in her blog post.

The oil layer is pretty dispersed, indicating that chemical dispersants broke it down into small droplets. In an interview with NPR, she also reported finding small tar balls that look like cauliflower heads. While dispersants likely helped some of the oil sink to the bottom, Joye said natural processes also played a role. As microorganisms break down oil, they excrete mucus, which eventually sinks to the bottom.

Government scientists acknowledge they have not done a good enough job looking for oil at the bottom of the sea. It’s partly because the environment is so difficult — teams have to use send 1,000-pound vessels to the seafloor where they can pull up core samples. The AP quoted a NOAA official saying government and BP vessels will plumb the depths in the coming weeks.

[AP]

Scientists have yet to agree on the scope of the disaster

But the new study is merely a rough snapshot of what is happening in the depths. Wide disagreement persists among scientists who study the Gulf and oil spills, and they say it could take generations to fully understand the leak’s scope. The best minds in marine science and geology can’t say yet how bad it will be.

Woods Hole Oceanographic Institution researchers Richard Camilli and Chris Reddy followed the plume starting about three miles from the wellhead of the deep-sea Macondo well. Using autonomous submersibles, they took samples for 22 miles, until the approach of Hurricane Alex forced them to turn back.

As of now, they don’t know how much oil (of the estimated 4.9 million barrels leaked) is in the plume, and they can’t be certain how diffuse it is until they analyze more water samples, Reddy said. The researchers say the levels of dissolved oxygen within the plume had not dropped to levels that would suggest bacteria were breaking down the oil in significant volumes.

The report comes two weeks after a government study that most researchers said was widely misinterpreted. Other scientists dismissed the report as inaccurate or incomplete. That report, from the National Incident Command (NIC), said the majority of the oil had evaporated, been recovered or been dispersed — but dispersed does not mean gone.

Rick Steiner, a retired professor at the University of Alaska and marine conservationist who worked on cleaning up the Exxon Valdez oil spill, called that report fatally flawed.

“The estimate that chemical dispersants were successful at dispersing 8 percent of the leaked oil [as stated in the NIC report] is, quite frankly, ludicrous,” he said in an e-mail message.

Many others agree, and at least two studies emerged this week that appear to directly contradict the government’s findings. But none of them proves anything conclusively. Reddy said government scientists, along with those at universities and private institutions, are trying to account for all the oil like balancing a checkbook. But a checkbook is difficult to balance when none of the numbers being used are firmly accurate.

“This data that we’re waiting for, as it becomes available, they will be able to put it into their calculations,” he said. “When we have analyzed those samples, we’ll be able to constrain what the inventory of those compounds was in there. And at that point, we may be able to see whether it’s a penny in a big checking account, or maybe it’s bigger.”

The problem is that every variable is couched in terms of estimates. Without a firm grasp on where the oil settled — at the surface, in the middle, or at the bottom of the sea — it’s nearly impossible to say what happened to it. The Woods Hole study uses oxygen as a proxy for microbial degradation, for instance. But scientists don’t have good baselines for pre-existing oxygen concentrations, so it’s hard to tell what has changed.

“In truth, no one really has any idea whatsoever of how much oil has gone where,” Steiner said.

Some estimates suggested 80 percent of it went to the surface, and if that’s so, then it’s reasonable to assume much of it is gone, according to Louisiana State University emeritus professor Ed Overton. Oil at the surface would quickly evaporate and be consumed by naturally present bacteria, he said.

Overton reviewed the NIC report and generally accepts its findings, though he believes the government may have underestimated how much oil remains below the surface. He said the visible evidence looks promising — surface slicks are disappearing, and things seem to be returning to normal. He went swimming off the coast of Alabama last week and said it was wonderful, though he did find a few tar balls. Work, not oil, forced him to return home.

“I could still be swimming if there wasn’t so much work to do associated with the spill,” he said.

Others don't seem quite as eager to dive in. Ron Kendall, chair of the department of environmental toxicology at Texas Tech and director of the university’s Institute for Environmental and Human Health, believes the oil’s persistence, as well as the profligate use of dispersants, could lead to entirely new environmental effects. He compared the dispersants to mineral spirits used to clean up oil spots in a garage.

“If you pour mineral spirits on your skin, it’ll burn. You breathe it, it’ll be very antagonistic to your sinuses. You drink it, it’ll be very harmful,” he said. “There were a lot of organisms that came into contact with the use of dispersants deep in the ocean, and on the surface.”

He thinks dispersants probably contributed to the plume’s presence. If the oil had not been dissipated into microdroplets as it was spewing from the well, more of it would have floated to the surface, he said.

“A lot of that oil, and the toxic constituents in that oil, has probably been dispersed into the water column, and that is what these scientific discoveries are finding out — there appear to be these plumes,” he said.

Adding to the confusion is the tricky element of politics. Plenty of research will be wrapped up in lawsuits, and scientists who are being hired by BP and legions of attorneys are being caught in the middle. Last month, NPR reported that BP is essentially buying the silence of prominent Gulf researchers. The public radio network quoted University of South Alabama's Bob Shipp, who said BP's lawyers tried to hire his whole Department of Marine Sciences to do research for them. Under the deal, the scientists could only disclose their findings if BP gave them a green light. Otherwise, they'd have to keep it secret for three years, NPR said.

“A lot of this event has been politicized, versus letting the scientists do their jobs and get the best science possible,” Kendall said. “It’s really hard for the science to rise to the top when everybody is getting ready for a big lawsuit, including the government.”

There’s at least one area in which scientists can agree: The impact on Gulf ecosystems will not be clear for years to come.

Kendall believes most of the leaked oil remains in the environment, and said it will take years to understand its impacts on wildlife like sea turtles, whales and bluefin tuna.

“It takes 10 years before those female (turtles) come back to nest, in the case of the coast of Texas, so we won’t know for a decade. So let’s not race to judgment. This is a time for good science,” he said.

Overton said more work is still needed to at least determine where the oil went.

“As soon as that damn oil quit coming into the Gulf, the amount of oil at the surface nearly disappeared. Now that doesn’t mean there is zero oil. There’s still oil on the marshy grass, some buried a foot or so down ... coastal erosion changes those beaches a lot. There’s tar balls out there like the ones I found.

“But what if, instead of 20 percent being spread at the bottom, what if 80 percent was down there, and all we were seeing at the surface was 20 percent? If that’s the case, then 80 percent of that oil is still down there, minus what is being degraded.”

Overton said he would not be surprised if there is still plenty of diluted oil beneath the surface — which the Woods Hole study suggests is plausible.

“The question is, can the dilute oil cause environmental impacts? We don’t know. We can’t know, because we don’t know very much about deepwater environments,” Overton said. “This is a question that may never be answered.”

If all this uncertainty indicates anything, it’s that much more data is needed before anyone — scientists or policymakers — attempts anything resembling declarative statements. Science is incremental, as Reddy said in today’s conference call. Individual studies are usually designed to address narrow questions, such as today’s glimpse at the plume’s size and spread. Further studies will address its toxicity, density and impacts on fish and other wildlife. It will be a long time before everything is tied together to paint a complete picture of this disaster.

Kendall said that research is only just beginning.

“To me, we’re still in the very early phases of this,” he said. “Quite frankly, we may not fully figure out the ultimate impact of this for many years to come.”