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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.”

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]

Miss the good old days of daily oil disaster news? Worry not, for another oil rig in the Gulf of Mexico exploded this morning, leaving all 13 crew members in the water but – according to initial reports – all are alive and only one is injured. The rig is owned by Mariner Energy (somewhere a BP exec is breathing again) and is not currently producing, according to the Coast Guard. Updated. Details are sketchy right now, but rescuers are en route to the site about 80 miles south of the central Louisiana coast. We'll update as this one develops.

Update: Reuters is reporting that the Coast Guard has spotted a one-nautical-mile by 100-foot oil sheen in the water at the site of the rig explosion. The fire has been contained, but the flames have not yet been completely extinguished.

Update: USA Today now reports that the initial claim of an oil sheen by Mariner Energy cannot be confirmed by the Coast Guard, and that an aerial flyover by Mariner personnel could not locate the oil sheen reported earlier. In other good news, the fire aboard the oil platform has now been extinguished.

[NYT]

The belt is made of an ultra-light nanowire mesh, patented at MIT, that can absorb up to 20 times its weight in oil. Its hydrophobic properties deflect water while sucking up various forms of pollution. The nanowire's inventors have compared it to a paper towel for oil spills.

The belt attaches to a yellow “head” covered in photovoltaic panels, according to its designers, based at MIT’s Senseable City Lab. As the robot moves head-first through the water, the conveyor belt sucks up oil, which is squeezed out into the head. As the clean part of the belt emerges from the head, the process starts over.

Seaswarm robots are intended to work as a fleet, hence the name. The robots would communicate via GPS and WiFi networks to coordinate clean-up, and they would not require human involvement, unlike current ocean skimmers. They are just 16 feet long by seven feet wide, so they would be able to access coastlines, marshes and estuaries, unlike current skimmers that attach to boats.

The design team tested their prototype in Boston’s Charles River this month and they say the conveyor belt easily adapted to the surface waves.

The robot works by detecting the edge of a spill and moving inward until it has removed the oil, the project's Web site says. Because the robot's head consumes the oil, the robot does not need to make repeated trips back to shore, making it a much more efficient cleaner.