Editor’s Note: Recent Updates on After Effects of BP Oil Spill in the Gulf of Mexico. Five articles follow.
NEW ORLEANS (AP) — After months of laboratory work, scientists say they can definitively finger oil from BP’s blown-out well as the culprit for the slow death of a once brightly colored deep-sea coral community in the Gulf of Mexico that is now brown and dull.
In a study published Monday, scientists say meticulous chemical analysis of samples taken in late 2010 proves that oil from BP PLC’s out-of-control Macondo well devastated corals living about 7 miles southwest of the well. The coral community is located over an area roughly the size of half a football field nearly a mile below the Gulf’s surface.
The damaged corals were discovered in October 2010 by academic and government scientists, but it’s taken until now for them to declare a definite link to the oil spill.
Most of the Gulf’s bottom is muddy, but coral colonies that pop up every once in a while are vital oases for marine life in the chilly ocean depths. The injured and dying coral today has bare skeleton, loose tissue and is covered in heavy mucous and brown fluffy material, the paper said.
“It was like a graveyard of corals,” said Erik Cordes, a biologist at Temple University who went down to the site in the Alvin research submarine.
So far, this has been the only deep-sea coral site found to be seriously damaged by the spill.
On April 20, 2010, the well blew out about 50 miles off the Louisiana coast, leading to the death of 11 workers aboard the Deepwater Horizon drilling rig and the nation’s largest offshore spill. More than 200 million gallons of oil were released.
She said pinpointing the BP well as the source of the contamination required sampling sediment on the sea floor and figuring out what was oil from natural seeps in the Gulf and what was from the Macondo well. Finally, the researchers matched the oil found on the corals with oil that came out of the BP well.
Also, the researchers concluded that the damage was caused by the spill because an underwater plume of oil was tracked passing by the site in June 2010. The paper also noted that a decade of deep-sea coral research in the Gulf had not found coral dying in this manner. The coral was documented for the first time when researchers went looking for oil damage in 2010.
The findings were published in the Proceedings of the National Academy of Sciences.
The scientists said that they have gone back to the dying corals by submarine since 2010, but that they are not ready to talk about what they’ve seen at the site.
However, Charles Fisher, a biologist with Penn State University who’s led the coral expeditions, said recovery of the damaged site would be slow.
“Things happen very slowly in the deep sea; the temperatures are low, currents are low, those animals live hundreds of years and they die slowly,” he said. “It will take a while to know the final outcome of this exposure.”
BP did not immediately comment on the study.
The researchers said the troubled spot consists of 54 coral colonies. The researchers were able to fully photograph and assess 43 of those colonies, and of those, 86 percent were damaged. They said 10 coral colonies showed signs of severe stress on 90 percent of the coral.
White, the lead researcher, said that this coral site was the only one found southwest of the Macondo well so far, but that others may exist. The researchers also wrote in the paper that it was too early to rule out serious damage at other coral sites that may have seemed healthy during previous examinations after the April 2010 spill.
Jerald Ault, a fish and coral reef specialist at the University of Miami who was not part of the study, said the findings were cause for concern because deep-sea corals are important habitat. He said there are many links between animals that live at the surface, such as tarpon and menhaden, and life at the bottom of the Gulf. Ecosystem problems can play out over many years, he said.
“It’s kind of a tangled web of impact,” he said.
Dolphins in Barataria Bay off Louisiana, which was hit hard by the BP oil spill in 2010, are seriously ill, and their ailments are probably related to toxic substances in the petroleum, the National Oceanic and Atmospheric Administration suggested on Friday.
As part of a continuing assessment of damages caused by the three-month spill, which began with an explosion aboard the Deepwater Horizon rig in the Gulf of Mexico, NOAA scientists performed comprehensive physicals last summer on 32 dolphins from the bay. They found problems like drastically low weight, low blood sugar and, in some cases, cancer of the liver and lungs.
Yet the most common symptom among the dolphins, found in about half the group, was an abnormally low level of stress hormones like cortisol. Such hormones regulate many functions in the animal, including the immune system and responses to threats. Scientists said the dearth of hormones suggested that the animals were suffering from adrenal insufficiency.
Lori Schwacke, the lead scientist for the health assessment, said the findings were preliminary and could not be conclusively linked to the oil spill at this point. But she said the exams were also conducted on control groups of dolphins living along the Atlantic coast and in other areas that were not affected by the 2010 spill and that those dolphins did not manifest those symptoms.
“The findings we have are also consistent with other studies that have looked at the effects of oil exposure in other mammals,” Dr. Schwacke added, citing experimental studies of mink that were dosed with oil. Some of those minks developed adrenal insufficiency.
Strandings of dolphins began rising in states along the Gulf of Mexico in February 2010, or about two months before the oil spill.
But NOAA says the strandings have returned to normal rates along the Florida coast, which was the farthest from the spill, while remaining abnormally high along the coasts of Louisiana, Mississippi and Alabama. In Barataria Bay alone, with a population of about 1,000 dolphins, 180 strandings have been reported since February 2010. In a normal year, about 20 dolphin standings would be reported in all of Louisiana, the agency said.
Ben Sherman, a NOAA spokesman, cautioned against drawing too broad a conclusion about dolphin deaths across the gulf from the findings. He said the results could provide “possible clues” to the effects of the oil spill on other dolphins in the northern Gulf of Mexico. “However, it is too soon to tell how the Barataria Bay findings apply,” he said.
Published March 22, 2012
As they walk the sands of Orange Beach, Alabama, T. Prabhakar Clement and Joel Hayworth have no difficulty finding traces of the Deepwater Horizon disaster—in fact, the Auburn University researchers have a harder time making sure those traces don’t stick to their feet.
On a mid-February weekend, oil—in the form of hundreds of sticky tar balls—had washed up all over the beach following a storm the night before.
“We could have collected as many tar balls as we wanted to, from less than 1 centimeter up to 4 centimeters (.4 to 1.6 inches) in diameter,” Clement said. “And these are really soft tar balls that are decaying, so there are probably also millions of tiny fragments that we can’t even see. I collected over 1,000 tar balls within [an area of] about 10 miles (16 kilometers) in five hours. What does that mean? I don’t know. What are the health ramifications? I don’t know. But this clearly demonstrates the magnitude of the [ongoing] problem attributable to Deepwater Horizon.”
(Related Quiz: “How Much Do You Know About the Gulf Oil Spill?“)
Tar balls are soft clumps of weathered oil mingled with sand, shells, and other beach material. They can range from the size of a pinhead to larger chunks, about the size of a basketball. And nearly two years after the deadly explosion that destroyed the Transocean oil rig Deepwater Horizon, and unleashed nearly 5 million barrels of oil into the Gulf of Mexico from BP’s Macondo well, the oil company’s cleanup personnel are still gathering them up along some Gulf beaches. But many beaches exhibit no tar balls, and even on beaches where tar balls do appear periodically, they aren’t present all the time. In fact, Clement and Hayworth stressed, those beaches often look just fine to the naked eye.
(Related Photos: “Gulf Oil Spill: Oiled Beaches Timeline“)
“It’s a very dynamic system,” Hayworth said. “After a run-of-the-mill storm you might come down, and the beach will look like it just got re-oiled. But then, there is so much movement of sand, the beach turns over quickly and the shoreline is constantly moving around. So you could show up as a tourist at any given moment, and it could look pretty pristine.” That may be because omnipresent BP crews pick up the tar balls whenever they appear, he said.
Tracing the Tar Balls
Not all tar balls are the result of the Deepwater Horizon disaster. Routine leaking in offshore oil operations, discharges from marine vehicles, onshore runoff, and even natural seepage from the ocean floor also create some. In fact, each day enough oil to fill 1,300 barrels of oil seeps naturally into the Gulf of Mexico, according to a 2002 report by the U.S. National Research Council of the National Academy of Sciences. But the Auburn researchers say their studies show that the vast majority of the oily tar balls still washing up in the Gulf are directly attributable to the spill.
(Related Photos: “Four New Offshore Drilling Frontiers“)
That is so, they say, even though the Shoreline Clean-up Completion Plan (SCCP) released in November by the Unified Command, the joint BP-federal-state entity coordinating the response to the Deepwater Horizon spill, noted that during six months of surveys across four states, cleanup teams found some 5,000 non-Deepwater Horizon tar balls.
“In light of this report, BP’s subtle suggestion is that other sources of contamination are possibly of the same magnitude as Deepwater Horizon,” Clement explained. “But we could have easily collected over 5,000 tar balls during our last survey day” on Orange Beach, he added. And it’s easy to trace tar balls back to Deepwater Horizon. As Unified Command reports make clear, the BP tar balls are 80 percent sand and break up easily. Those physical properties make them unlike those of other Gulf tar balls, and easy to identify in the field, even without chemical “fingerprinting,” according to the SCCP report.
“Also, the numbers tell the story, when you see several hundreds and thousands at a specific location [where tar balls have] never occurred before on our shores,” Clement added.
What Happened to All That Oil?
Markus Huettel, a benthic ecologist at Florida State University, has been researching the status of Deepwater Horizon oil on Florida Panhandle beaches since June 2010. Huettel explained that while much of the BP well’s oil was degraded or evaporated. A staggering amount—he suggests 60 percent is a conservative estimate—remains unaccounted for.
NOAA has developed an Oil Budget Calculator tool to compile research data and show scientists’ best guesses about what happened to all the oil from the worst spill in U.S. history. But Huettel cautioned that the fate of only one category, the 17 percent directly recovered from the wellhead, is actually known.
“All the other categories—like oil burned, skimmed, chemically dispersed, or evaporated—are guesses that could change by a factor or two or even more in some cases,” Huettel said.
“It’s still just a lot of arm-waving, unfortunately, at this point,” he said. Ongoing research will help scientists learn what happened to more of the oil over time, Huettel stressed, but some categories, like how much oil was dispersed at depth, will never be accurately known. “That oil is somewhere, but nobody knows where, and nobody knows how much has settled on the seafloor. We really only know the oil we have in hand, that 17 percent. All the rest is very debatable.”
(Related Photos: “Gulf Oil Spill: Tarballs, Oil Hit Beaches“)
One hypothesis suggests that much of the oil ended up in “tar mats.”
“These mats would likely be covered under sand and sediment, then uncovered during storm conditions where they are subject to erosion and deposition on the shore,” Huettel said. “There are pockets where many more of these tar balls come up on shore, and the idea is that there may be some underwater dips or depressions where this oil can accumulate. Then, the sand and waves grind them into pieces.”
Jacqueline Michel, a geochemist who is the U.S. National Oceanic and Atmospheric Administration (NOAA) coordinator for the Shoreline Clean-up Assessment Program, is leading the survey of more than 4,373 miles (7,038 kilometers) of shoreline extending over four states. Her teams are familiar with near-shore tar mats, and have been removing them where possible.
“We’ve done quite a bit of work looking for them and we’ve found that most of the oil not buried on the beach is very close to shore, between the beach and that first sand bar,” she said. “You can reach it in the surf zone with a long-arm excavator. That’s where we see the balls coming ashore as they break off from those [deposits], and we’ve made a big effort to get those.”
The Shoreline Cleanup and Assessment Teams (SCAT) led by NOAA and the U.S. Coast Guard include representatives from state agencies as well as BP. (Visit RestoreTheGulf.gov for more information.) They’ve been digging such mats out wherever possible, using excavators with screened buckets on the end, Michel said. Sometimes, she added, they get a considerable assist from Mother Nature.
“Hurricanes or tropical storms can play a very important role in this process,” she said. “Tropical Storm Lee [in September 2011] really released a lot of this kind of oil to the beaches and we were able to get a lot of that oil out of the environment. Crews patrol the beaches and pick up what they see on the surface, but we can really depend on some help from these natural processes.” In that sense, Michel reports, a small and totally non-destructive hurricane would actually be almost welcome in terms of accessing oil for cleanup.
Cleanup Quandary: How Much is Too Much?
Michel explained that her teams have tackled an enormous task over the past two years. “The current oiling, where you still see anything on the shoreline, is around 450 miles (724 kilometers) as of February 25,” she said. That area is scattered across the eastern Gulf from Louisiana to Florida, she said.
(Related Story: “Oiled Gulf Beaches During and After: Zoomable Maps“)
Their efforts have removed a large amount of oil from the environment that once covered 1,096 miles of shoreline, though scientists like Clement and Hayworth bemoan the fact that hard data on just how much has been removed by the joint government-BP cleanup effort hasn’t been made available to them. Today, the pressing question in many locations is just when cleanup efforts should wind down.
For beaches, Michel added, the team’s goal is to clean up to the point at which there is no visible Deepwater Horizon oil at all. For marshes, which are both more difficult to clean, and more sensitive to damage from foot and vehicle traffic, it is tougher to evaluate how much cleanup should be attempted. In either case, it isn’t always cut-and-dried exactly when cleanup efforts should stop, she emphasized.
(Related Photos: “Heavy Oil Seeping Into Louisiana Marshes“)
“This oil had to go 50 to 150 miles (80 to 240 kilometers) before it came to shore and also rise through 5,000 feet (1,525 meters) of water, so we call it ‘water washed,’ and then it was buried,” Michel said. “Federal and state agencies have determined that this really poses no human health risk, and often little risk to wildlife.” In some cases, officials thought it was better to leave the buried oil be. “Sometimes, they didn’t want to dig up a lot of their beaches,” she said.
At Alabama’s hard-hit Bon Secour National Wildlife Refuge, manager Jereme Phillips said the impacts of the spill are greatly reduced from a year ago, As a result, he said, so is the cleanup effort, which went on for seven days a week for the first year after the spill. Now, it is down to one day per week. Tar balls still do wash up here regularly, particularly after strong winds or rough seas.
“We want to remove as much as possible from our beaches,” he said. “But we want to ensure that the cleanup operations, workers, ATVs, and other equipment aren’t doing more harm than good to sensitive ecological areas like bird-nesting sites,” he said. “We’re approaching bird-nesting season, for example, and we want to make sure that cleanup wouldn’t negatively impact the refuge even more than the oil.”
One problem, Phillips said, is determining what threats the oil might pose. “We don’t fully understand what all the impacts of the oil may be,” he said. “It’s a contaminant and we want to remove as much of it as possible from the refuge, but we want to do that in a way that minimizes ecological impacts.”
Auburn’s Joel Hayworth agreed that the oil’s ecological impacts remain a puzzle. “How is this oil being used and broken down by the organisms that reside in these areas?” he asked. “Recent studies show that microbiological communities that reside in the sandy beach systems, in fact, have been affected by oil. How do changes at the microbiological level propagate up the ecosystem? The details are very complex and scientists are trying to unravel the reality of what happens to a north Gulf of Mexico sandy beach system when you hit it with a whole bunch of oil.”
The problem has produced a long-running natural experiment with no known end date, because that buried oil isn’t likely to go away anytime soon, Florida State’s Markus Huettel said. “Unfortunately, when oil sits in sediments it’s typically excluded from oxygen contact, so its degradation is slowed down dramatically.”
Spokesman Tom Mueller, of BP America’s office in Houston, Texas, said the bulk of the mechanical and manual cleanup effort is complete, but patrolling and maintenance will continue until data demonstrates that shorelines meet standardized specifications as determined by the federal on-scene coordinator, currently U.S. Coast Guard Capt. Duke Walker.
“So we continue focusing cleanup resources on those few areas where we see continuing incidences of tar balls or other impacts, while working with state and federal agencies to remove other areas from the response and into restoration phase,” Mueller said.
“BP has committed up to $1 billion for early restoration projects,” he added. “While the normal Natural Resource Damage assessment process takes years to complete—with restoration funding to follow—BP is making funding available today to help restore areas where we know there were coastal or wildlife impacts from the spill. State and federal trustees oversee the allocation of funding for these early restoration projects, the first group of which were announced earlier this year.” (Details of those projects can be found here.)
For now, the scientists combing the beaches say it is important to continue studying the BP spill oil, its fate in the environment, and its impacts.
“The Gulf is full of wells and pipelines,” said Auburn’s Joel Hayworth. “We’re in the age of hydrocarbon man, and this isn’t only an interesting natural experiment, it’s a harbinger of the future. We’ve got to understand what is going on here now, so we can prepare for the next time.”
This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.
ScienceDaily (Mar. 8, 2012) — Crabs, insects and spiders living in coastal salt marshes affected by the 2010 Deepwater Horizon disaster were damaged by the massive oil spill but were able to recover within a year if their host plants remained healthy, according to a University of Houston study published March 7 in the open access journal PLoS ONE.
In one of the first studies to look at how oil spills affect salt marsh arthropods, Brittany McCall, a UH graduate student, and biology professor Steven Pennings, her adviser, sampled terrestrial arthropods and marine invertebrates at the time of the oil spill, as well as a year later.
The April 2010 explosion aboard the Deepwater Horizon resulted in a massive oil spill in the Gulf of Mexico that washed ashore, damaging a number of coastal areas.
McCall and Pennings received a grant from the National Science Foundation to study some of the coastal salt marshes affected by the spill. They gathered samples in areas where relatively low levels of oil were present but the plants still appeared healthy and undamaged. They found that in these areas, the numbers of crabs, insects and spiders were reduced by up to 50 percent because of the oil exposure.
“This study demonstrates that appearances can be deceiving,” Pennings said. “Arthropods are quite vulnerable to oil exposure. These results are very important because they show that we can’t assume that the marsh is healthy just because the plants are still alive.”
However, the fact that some plant life remained intact in these areas apparently was key to how the arthropods recovered. When the UH researchers sampled the same areas a year later, all three groups appeared to have recovered, suggesting that arthropods affected by oil may recover if their host plants remain healthy.
“Salt marshes are commonly disturbed by natural events and, as a result, they may be able to also recover from oil spills if the oil disturbance is not too large,” Pennings said.
Oil spills pose a major threat to coastal wetlands, but the exact environmental costs are difficult to measure because experiments cannot replicate large environmental catastrophes.
Because each oil spill is different, McCall and Pennings cautioned against extrapolating their results to all oil spills.
“The effect of oil on the marsh is likely to vary depending on how much oil gets ashore and how much it has weathered,” McCall said. “In the case of the Deepwater Horizon oil spill, the marshes may have dodged a bullet because relatively little oil made it into the marshes, and the oil had weathered for several weeks.”
By Alisha Renfro, Ph.D., National Wildlife Federation
Researchers examined oiled marsh during the 2010 BP Gulf oil spill. (Credit: http://www.darrp.noaa.gov)
The BP oil disaster introduced more than 200 million gallons of crude oil into the Gulf of Mexico, just off the southeastern Louisiana coast. An extensive effort is currently underway to assess the full damage of this catastrophic event on the rich and complex Gulf ecosystem.
A study lead by Deepak Mishra, Ph.D. and published in Remote Sensing of Environment (vol. 118) is the first look at short-term impacts the oil spill had on the salt marshes of southeastern Louisiana. The study, “Post-spill state of the marsh: Remote estimation of the ecological impact of the Gulf Of Mexico oil spill on Louisiana Salt Marshes,” examines the impact of the oil, dispersants and cleanup efforts on salt marshes in the months following the spill. Researchers used field measurements and satellite imagery from 2009 and 2010 to compare characteristics of vegetation related to health and productivity before and after the spill.
Oil can have a direct and immediate impact on salt marsh health by coating the vegetation and soil surface, leading to temperature stress and a reduction in photosynthesis. Compounds found in crude oil can also negatively affect the ability of salt marsh vegetation to tolerate salinity, leading to vegetation dieback and slowing down marsh recovery. And while oil can have a damaging affect on marshes, cleanup efforts such as skimming, oil collection and burning can cause additional damage.
For the study, the research group identified and sampled marsh plots ranging from no oil present to heavily-oiled during the post-spill growing season. Measurements of different vegetation characteristics were taken at the field sites and used to calibrate models that were then applied to satellite imagery from the 2009 and 2010 growing seasons (April-October). Fortunately, 2009 and 2010 were years with similar variations in temperature and precipitation, as well as no hurricanes or other disturbances that directly affected the area, except for the oil spill.
The research suggests that during the pre-spill growing season (2009), there were roughly 32 square miles of salt marsh that exhibited markers of vegetative stress and decreased productivity. After the spill, this area of stressed marsh increased dramatically to around 250 square miles. It is important to note that while the increase of stress and reduced productivity in a salt marsh is not directly related to land loss, loss can occur as a result of a weakened root system – increasing the vulnerability of salt marsh to erosion from waves, tides and storm events.
The long-term effects of the oil spill on the large and complex Gulf ecosystem are not yet known, but this first look at the short-term impact to the salt marshes of southeastern Louisiana indicates that the damage directly related to the oil spill may be significant. Some recovery of oiled marshes has been observed, but the residual oil on Gulf Coast salt marshes will have a long-term impact on overall marsh health and productivity for years to come.