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sydneyst
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 Posted: Wed May 26th, 2010 12:05 pm

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Top Kill to Proceed May 26,2010

http://www.nola.com/news/gulf-oil-spill/index.ssf/2010/05/if_successful_top_kill_will_pe.html






John McCusker/The Times-PicayuneThese pelicans were photographed Tuesday on an oil-soaked island near Grand Isle. Armed with 50,000 barrels of mud, BP will attempt today to permanently stop the flow of oil from a broken Gulf of Mexico well. If the effort, called a "top kill," is successful it would bring to an end a monthlong expulsion of oil into the Gulf. If the maneuver is not successful BP will contain the spill as best it can until another method of permanently shutting off the flow of oil -- drilling of a relief well -- is complete this summer.

Either way, the nation, and especially the residents of the Gulf Coast, will be watching and anxiously awaiting the result as BP tries to pull off a procedure that has never been performed at 5,000 feet below the water's surface.





Click to see a larger version of the Top Kill operation graphic.

The top kill process involves using a 30,000-hydraulic-horsepower engine to pump fabricated "kill mud," which is about twice the density of water, into the well at 40 to 50 barrels a minute to overcome the flow of oil.

The material will be pumped from a vessel on the surface down a 6 5/8-inch drill pipe and into a set of 3-inch hoses attached to the choke and kill lines of the blowout preventer, which failed to seal the well after the rig exploded. If all goes well, the mud will push the oil back into the reservoir. Choke and kill lines are used to control the amount and pressure of drilling mud in the wellbore so that surges of oil and natural gas can be kept under control.

The top kill will be performed near the smaller of the two leaks. The second, larger leak, has been affixed with a tube that is capturing some, but not all, of the oil and natural gas spilling from it. Because the top kill will be performed at the base of the broken pipe, down near the blowout preventer, it should permanently shut off both leaks if it is successful.

The procedure has at least one immediate risk. If the mud is unable to overcome the flow of the oil, it could go back up the blowout preventer lines and find its way into the broken riser pipe, causing the pipe to erode and more leaks to form.

Kent Wells, BP's senior vice president for exploration and production, appeared less concerned that damage to the casing pipe, which extends beneath the sea floor would pose a problem, though he said the company did not have a wealth of data about the condition of the pipe after the explosion.

"I think there's a lot of things that we don't know for sure," Wells said. "So what we're trying to prepare for is a top kill procedure that is successful in any case."

Tony Hayward, BP's chief executive officer, said Monday that there is a 60 percent to 70 percent chance the procedure will be successful. It could take "half a day to a couple days" to find out if it has succeeded, Wells said.

...Smith said he plans to watch the attempt live if it is aired. BP said Tuesday night that a live feed of the spill on the company's website will remain active during the top kill effort.
Although the spill has not caused many vessels to abandon the Port of New Orleans in favor of other ports, it has added to shipping costs as vessels pause to have their hulls cleaned of oil before entering the river and take detours to avoid traveling through spill sites. As oil continues to spill the threat of cancellations grows, said John Hyatt, vice president of Irwin Brown Co., a freight forwarder.

BP says that the top kill has been a part of its plan to shut the well for weeks but the procedure needed to be studied because it has never been attempted at 5,000 feet below the water's surface. The company also had to disconnect, bring to the surface, test, repair and reconnect the control center that will manipulate the valves in the blowout preventer that will direct the mud's flow.

The process, along with building materials to complete the procedure, usually takes months, Wells said.

"In terms of the top kill, we've actually been designing the top kill since day one," Wells said. "The pace at which this has been done is far faster than what we're typically able to do at this depth."

With all of its equipment now staged at the site, scientists from BP and the Minerals Management Service spent Tuesday performing diagnostic tests on the failed blowout preventer. BP was testing five points on the blowout preventer to ensure they could withstand the pressure of the mud flowing down the five-story apparatus. The test results will guide BP's approach to filling the well.

Unfavorable test results could push back the top kill attempt and possibly cancel it altogether, although the latter is unlikely, Wells said.

"That is always a possibility," Wells said, referring to canceling top kill altogether. But he called the chance that it would happen "remote."

"At the end of the day, we have one priority and that's to shut off the well."

If the top kill doesn't immediately work, BP will try supplementing the effort with a "junk shot." The junk shot involves shooting debris, such as tennis balls and pieces of rubber tire, into the blowout preventer to clog the oil. That would be followed by another attempt at the top kill.

But Wells said BP wants to avoid putting those "bridging agents" down the pipe because they may block the lines in places the company doesn't want.

If the top kill and junk shot combination fails, the company said it will try to contain the oil by removing the broken riser pipe from the blowout preventer and affixing the blowout preventer with a cap attached to a riser tube that will suction oil from the well and feed it to a ship on the surface. The cap will have a seal to keep water from entering the pipe and creating ice crystals that could block oil flow.

"We naturally are praying that this procedure will work, obviously," Briggs said. "We're as anxious as everyone is."




Last edited on Wed May 26th, 2010 07:46 pm by sydneyst

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 Posted: Sun May 23rd, 2010 10:37 pm

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Loop Current Temporarily Destabilizes--
Could Lessen Immediate Threat to Florida


 http://www.eenews.net/public/Greenwire/2010/05/20/2

05/20/2010)A large rotating cyclone of cold water is pushing into the southern body of the Gulf of Mexico's Loop Current and now appears likely to destabilize or even sever the current and the oil it contains from its connection to Florida, scientists said today.

While the BP PLC oil spill has begun to enter the current, a powerful stream that could transport a small part of the slick to the Florida Keys in about a week, there are also signs that less oil -- at least on the surface -- has taken the turn south that was feared.

Over the past weeks, small ocean flows spinning off the body of the Loop Current, known as cyclones or eddies, have pushed and prodded the Gulf slick. In particular, one counterclockwise eddy east of the oil's main body has determinedly dragged the crude toward the main current, resulting in its current entrainment (Greenwire, May 18).



Satellite imagery today of the Loop Current has revealed a large cyclone (C1) that is threatening to destabilize or even sever the current's head. Little of the oil slick's "tail" has been entrained into the current so far, most caught in an eddy (C2) just north of the current. Map courtesy of Nan Walker. Click the map for a larger version.


More importantly, Roffer said, satellite shots this morning showed that an eddy farther south along the Florida coast is expanding in size and strength. That cyclone appears likely to destabilize or even sever the Loop Current, greatly reducing the oil threat to the Florida Keys and beyond, he said.


"If it forms, it's going to pull a lot of the oil away from Florida," Roffer said. There are no guarantees, he added, "but it looks very likely that this is forming."

Such a beheading is common to the current, which becomes more unstable as it pushes deeper into the Gulf of Mexico. Typically, a forceful counterclockwise cyclone near southwest Florida "punches through the Loop Current," severing the flow from its connection to the Atlantic, said Nan Walker, the director of the Earth Scan Lab at Louisiana State University's School of the Coast and Environment.

"It looks like that kind of scenario is imminent," Walker said.

After a severing, the warm rotating water of the Loop Current's head -- called a "ring" -- begins to flow west toward Texas. But the ring can dawdle, too, and sometimes reattaches with the main current. Such fluctuations defy forecasting and remain an active area of research (Greenwire, May 5).

"At this stage, it's a watch and waiting game," Walker said.

Loop rings tend to survive for about six months as they drift toward Texas, said Frank Muller-Karger, a professor of biological oceanography at the University of South Florida. Scientists have little idea how much oil could be captured by such a ring and pulled westward.

Even if the large southeastern eddy does not sever the current, it could capture oil that would have otherwise made its way to the Florida Keys, said Villy Kourafalou, a Gulf of Mexico modeler at the University of Miami's Rosenstiel School of Marine and Atmospheric Science.

'Impossible to predict' It is too soon for East Coast residents to breathe a sigh of relief, however. Oil is still bobbing 120 miles off Tampa's coast, captured in the northern eddy, and before the Loop Current expires -- if it does -- it could still surge north and entrain more of the oil, Walker said. Or it could be caught in a ring and flow westward.

The oil tendrils -- which federal officials have called a "sheen" -- are extremely visible on satellite imagery, suggesting to Walker that there is heavier oil present in the northern eddy than has been suggested. The government may be employing some "wishful thinking" when they call it a sheen, she said.

Also, there is little certainty about how much oil has been captured by the Loop Current in deeper waters. Since much of the oil has been broken up by dispersants and is unlikely to reach the surface, it will tend to spread sideways through the Gulf, Muller-Karger said.
"Just the same we see at the surface, where the oil is being entrained into the Loop Current, I can imagine that the same thing is happening at depth, that oil is being entrained and moving around and spreading with these currents," he said. "Now what the impact is? It's impossible to predict."

"Based on the size of the plume and the estimates that we're hearing of what is being injected at the bottom, this is a very large problem," Muller-Karger added.

The deep ocean is not a complete unknown, and oceanographers are working with the government to model how the oil may be spreading, Kourafalou said.

"We know that there are counterflows and counter-rotating eddies ... and we know that circulation is much slower," she said. "Some data sets exist and have allowed the study of basic underlying dynamics. What does not exist is a comprehensive, sustained, observational system."

While the Loop Current may be headed toward a severing, that will not stop oil from slowly spreading across the Gulf, especially when the hurricanes begin to hit, Walker said. Some of the oil is almost certain to affect countries like Cuba and Mexico, Muller-Karger added.
"This is a problem," he said, "that we'll have to deal with for years, as opposed to months."


Last edited on Wed Jun 2nd, 2010 07:43 am by sydneyst

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 Posted: Sun May 23rd, 2010 09:33 pm

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Desperate Measures: Water Diversions Used to Protect Wetlands
Louisiana using Mississippi River diversions in Gulf oil spill battle

By The Times-Picayune

May 13, 2010, 11:26AM

The state has opened gates at the Bayou Lamoque freshwater diversion in Plaquemines Parish to use Mississippi River water to help protect the parish's fragile network of wetlands.

The opening will send around 7,500 cubic feet per second of river water into wetlands adjacent to Black Bay and Breton Sound, the state Office of Homeland Security and Emergency Preparedness said.

The hope is that the river water will help push any oil from the Gulf oil spill away from the coastal wetlands.

"The potential effects of this oil spill could last for decades, so we are using every means at our disposal to try to lessen the devastation the oil could inflict on our wetlands," Louisiana Wildlife and Fisheries Department Secretary Robert Barham said.

Garret Graves, chairman of the Louisiana Coastal Protection and Restoration Authority, said the Lamoque diversion joins several others already pressed into service.

"We have been using diversions, siphons and locks on both the east and west side for more than 10 days to try and push the oil away from our coastal wetlands. Louisiana's coastal wetlands are a maze of marshy islands, grass beds, bayous, ponds and lakes. It will be nearly impossible for us to clean the oil out of these areas for years if it gets in there," Graves said.

The state said seven diversions and siphons and one navigation lock are now in use to send river water into the coastal wetlands. The total measurable flow from these diversions is 29,550 cubic feet per second.

They are:

- Bayou Lamoque Diversion: Plaquemines Parish. 7,500 CFS (capacity 12,000)
- Davis Pond Diversion: St. Charles Parish. 10,650 CFS (capacity 10,650)
- Violet Siphon: St. Bernard Parish. 200 CFS (capacity 200)
- Caernarvon Diversion: St. Bernard Parish. 8,000 CFS (capacity 8,800)
- Whites Ditch Siphon: Plaquemines Parish. 200 CFS (capacity 200)
- Naomi Siphon: Plaquemines Parish. 1,500 CFS (capacity 1500)
- West Pointe A la Hache Siphon: Plaquemines Parish. 1,500 CFS (capacity 1500)

Officials are also considering utilizing the Bohemia Spillway in Nairn to send river water into the wetlands.

Last edited on Sun May 23rd, 2010 09:34 pm by sydneyst

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 Posted: Fri May 21st, 2010 06:30 pm

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Latest Mapping of Massive Discharge

http://www.nola.com/news/gulf-oil-spill/index.ssf/2010/05/may_21_forecast_size_and_densi.html

May 21 forecast: Size and density of Gulf of Mexico oil spill By Emmett Mayer III, The Times-Picayune May 20, 2010, 6:56PM


View full size



The size and shape of the oil spill in the Gulf of Mexico changes by the day, depending on weather conditions as well as conditions in the Gulf itself.

This graphic shows the forecast for Friday, May 21. The shapes of the oil slick are created from information by pilots during flyovers, as well as trajectories created by the National Oceanic and Atmospheric Administration Thursday.

Last edited on Fri May 21st, 2010 06:31 pm by sydneyst

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 Posted: Fri May 21st, 2010 06:22 pm

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Gulf Turtle Deaths Triple Normal Number

http://www.nola.com/news/gulf-oil-spill/index.ssf/2010/05/dead_sea_turtles_on_gulf_of_me.html

By Mark Schleifstein, The Times-Picayune May 18, 2010, 1:55PM There have been 162 sea turtle strandings along the coast of the Gulf of Mexico between the Texas/Louisiana border and the panhandle of Florida this month, which could be triple the average number of dead turtles found on those beaches during May in the past five years, a NOAA senior scientist said today.



David Quinn / The Associated PressA dead sea turtle lays on the beach in Pass Christian, Miss., last week.

While necropsies -- animal autopsies -- of 156 of the turtles are not complete and the turtle corpses were not visibly oiled, the deaths seem linked to the spreading pool of Gulf of Mexico oil offshore from the Deepwater Horizon rig explosion, said Steve Murawski, NOAA Fisheries director of science programs, during a teleconference with reporters.

That compares to an average stranding rate of 47 for the past five years, he said.
"The stranding rate is significantly higher than background levels," Murawski said. "I have to caution that a little bit, though, because of the increased effort of looking for turtles now, compared to before the spill."

Scientists also are investigating a dozen bottlenosed dolphin fatalities and 23 dead oiled birds that have been recovered along the coast. There have been a dozen live oiled birds captured, with eight having been cleaned so far, and four have been released, said officials with the U.S. Fish & Wildlife Service.

But the effects of the release of millions of gallons of oil and the use of hundreds of thousands of gallons of chemical dispersants up on organisms and habitat areas away from the shoreline will be much more difficult to assess, the scientists said.
"The impacts are difficult to detect offshore because the area is difficult to observe," Murawski said. "But the long-term impacts of this event are likely to express themselves for years to come."

He pointed out that the oil release occurred at the height of the springtime spawning season for a wide variety of fisheries and marine mammals that live along the northern Gulf coast.

And it's also the beginning of nesting season for some of the species of sea turtles that forage for food in the Gulf.

The turtle strandings are largely juvenile Kemp's Ridley turtles that were populating a major feeding ground just offshore. Adults of that species, which is on the endangered species list, may have been spared because most are nesting on beaches in Mexico, he said.



Last edited on Fri May 21st, 2010 06:26 pm by sydneyst

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 Posted: Thu May 20th, 2010 07:56 pm

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Scientists Fault Lack of Studies Over Gulf Oil Spill


http://www.nytimes.com/2010/05/20/science/earth/20noaa.html

  By JUSTIN GILLIS

Tensions between the Obama administration and the scientific community over the gulf oil spill are escalating, with prominent oceanographers accusing the government of failing to conduct an adequate scientific analysis of the damage and of allowing BP to obscure the spill’s true scope.
 
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The scientists assert that the National Oceanic and Atmospheric Administration and other agencies have been slow to investigate the magnitude of the spill and the damage it is causing in the deep ocean. They are especially concerned about getting a better handle on problems that may be occurring from large plumes of oil droplets that appear to be spreading beneath the ocean surface.

The scientists point out that in the month since the Deepwater Horizon oil rig exploded, the government has failed to make public a single test result on water from the deep ocean. And the scientists say the administration has been too reluctant to demand an accurate analysis of how many gallons of oil are flowing into the sea from the gushing oil well.

“It seems baffling that we don’t know how much oil is being spilled,” Sylvia Earle, a famed oceanographer, said Wednesday on Capitol Hill. “It seems baffling that we don’t know where the oil is in the water column.”

The administration acknowledges that its scientific resources are stretched by the disaster, but contends that it is moving to get better information, including a more complete picture of the underwater plumes.

“We’re in the early stages of doing that, and we do not have a comprehensive understanding as of yet of where that oil is,” Jane Lubchenco, the NOAA administrator, told Congress on Wednesday. “But we are devoting all possible resources to understanding where the oil is and what its impact might be.”

The administration has mounted a huge response to the spill, deploying 1,105 vessels to try to skim oil, burn it and block it from shorelines. As part of the effort, the federal government and the Gulf Coast states have begun an extensive effort to catalog any environmental damage to the coast. The Environmental Protection Agency is releasing results from water sampling near shore. In most places, save for parts of Louisiana, the contamination appears modest so far.

The big scientific question now is what is happening in deeper water. While it is clear that water samples have been taken, the results have not been made public.

Lisa P. Jackson, administrator of the Environmental Protection Agency, told Congress on Wednesday that she was pressing for the release of additional test results, including some samples taken by boats under contract to BP.

While the total number of boats involved in the response is high, relatively few are involved in scientific assessment of the deep ocean.

Of the 19 research vessels owned by NOAA, 5 are in the Gulf of Mexico and available for work on the spill, Dr. Lubchenco said, counting a newly commissioned boat. The flagship of the NOAA fleet, the research vessel Ronald H. Brown, was off the coast of Africa when the spill occurred on April 20, and according to NOAA tracking logs, it was not redirected until about May 11, three weeks after the disaster began. It is sailing toward the gulf.

At least one vessel under contract to BP has collected samples from deep water, and so have a handful of university ships. NOAA is dropping instruments into the sea that should help give a better picture of conditions.

On May 6, NOAA called attention to its role in financing the work of a small research ship called the Pelican, owned by a university consortium in Louisiana. But when scientists aboard that vessel reported over the weekend that they had discovered large plumes undersea that appeared to be made of oil droplets, NOAA criticized the results as premature and requiring further analysis.

Rick Steiner, a marine biologist and a veteran of the 1989 Exxon Valdez disaster, assailed NOAA in an interview, declaring that it had been derelict in analyzing conditions beneath the sea.

Mr. Steiner said the likelihood of extensive undersea plumes of oil droplets should have been anticipated from the moment the spill began, given that such an effect from deepwater blowouts had been predicted in the scientific literature for more than a decade, and confirmed in a test off the coast of Norway. An extensive sampling program to map and characterize those plumes should have been put in place from the first days of the spill, he said.

“A vast ecosystem is being exposed to contaminants right now, and nobody’s watching it,” Mr. Steiner said. “That seems to me like a catastrophic failure on the part of NOAA.”

Mr. Steiner, long critical of offshore drilling, has fought past battles involving NOAA, including one in which he was stripped of a small university grant financed by the agency. He later resigned from the University of Alaska at Anchorage and now consults worldwide on oil-spill prevention and response.

Oceanographers have also criticized the Obama administration over its reluctance to force BP, the oil company responsible for the spill, to permit an accurate calculation of the flow rate from the undersea well. The company has refused to permit scientists to send equipment to the ocean floor that would establish the rate with high accuracy.

Ian MacDonald of Florida State University, an oceanographer who was among the first to question the official estimate of 210,000 gallons a day, said he had come to the conclusion that the oil company was bent on obstructing any accurate calculation. “They want to hide the body,” he said.

Andrew Gowers, a spokesman for BP, said this was not correct. Given the complex operations going on at the sea floor to try to stop the flow, “introducing more equipment into the immediate vicinity would represent an unacceptable risk,” he said.
Thad W. Allen, the Coast Guard admiral in charge of the response to the spill, said Wednesday evening that the government had decided to try to put equipment on the ocean floor to take accurate measurements. A technical team is at work devising a method, he said. “We are shoving pizzas under the door, and they are not coming out until they give us the answer,” he said.

Scientists have long theorized that a shallow spill and a spill in the deep ocean — this one is a mile down — would behave quite differently. A 2003 report by the National Research Council predicted that the oil in a deepwater blowout could break into fine droplets, forming plumes of oil mixed with water that would not quickly rise to the surface.

That prediction appeared to be confirmed Saturday when the researchers aboard the Pelican reported that they had detected immense plumes that they believed were made of oil particles. The results were not final, and came as a surprise to the government. They raise a major concern, that sea life in concentrated areas could be exposed to a heavy load of toxic materials as the plumes drift through the sea.  Under scrutiny from NOAA, the researchers have retreated to their laboratories to finish their analysis.

In an interview, Dr. Lubchenco said she was mobilizing every possible NOAA asset to get a more accurate picture of the environmental damage, and was even in the process of hiring fishing vessels to do some scientific work.
“Our intention is to deploy every single thing we’ve got,” Dr. Lubchenco said. “If it’s not in the region, we’re bringing it there.”

Robert Gebeloff, Andrew W. Lehren, Campbell Robertson and Matthew L. Wald contributed reporting.

Last edited on Thu May 20th, 2010 08:05 pm by sydneyst

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 Posted: Thu May 20th, 2010 06:52 pm

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Gulf Oil Again Imperils Sea Turtle
http://www.nytimes.com/2010/05/19/science/earth/19turtle.html

By LESLIE KAUFMAN Published: May 18, 2010 v

The Kemp's ridley turtle, whose numbers plummeted after an oil rig blowout in 1979, are in danger from the latest giant spill.



More Photos »

The sea turtle, affectionately nicknamed Thelma by a National Park Service employee, has already beaten some terrible odds. Still in the egg, she was airlifted here from Mexico in the years after the 1979 blowout of the Ixtoc 1 rig, which spilled millions of gallons of oil into the Gulf of Mexico and covered the turtles’ primary nesting place.

Now Thelma and others of her species are being monitored closely by worried scientists as another major oil disaster threatens their habitat. Federal officials said Tuesday that since April 30, 10 days after the accident on the Deepwater Horizon, they have recorded 156 sea turtle deaths; most of the turtles were Kemp’s ridleys. And though they cannot say for sure that the oil was responsible, the number is far higher than usual for this time of year, the officials said.



The Deepwater Horizon spill menaces a wide variety of marine life, from dolphins to blue crabs. On Tuesday, the National Oceanic and Atmospheric Administration expanded a fishing ban in the gulf because of the spreading oil. But of the endangered marine species that frequent gulf waters, only the Kemp’s ridley relies on the region as its sole breeding ground.


Since the Ixtoc 1 spill, the turtles, whose numbers fell to several hundred in the 1980s, have made a fragile comeback, and there are now at least 8,000 adults, scientists say. But the oil gushing from the well could change that.


The turtles may be more vulnerable than any other large marine animals to the oil spreading through the gulf. An ancient creature driven by instinct, it forages for food along the coast from Louisiana to Florida, in the path of the slick.


“It lives its entire life cycle in the gulf, which is why we are so critically concerned,” said Dr. Pat Burchfield, a scientist at the Gladys Porter Zoo in Brownsville, Tex., who has studied the turtle for 38 years.

The nesting season for the sea turtles runs until mid-July, and for most of that time the mothers will remain off Padre Island and the beaches of Mexico, where there is currently no oil. But then things become more chancy, as new sea turtle babies go off to sea, floating on currents in the gulf or on seaweed patches that could be covered by crude. Hungry after egg-laying, adult females are known to go to the mouth of the Mississippi, a particularly rich feeding ground, to replenish themselves.

Juvenile turtles, who stay off the shore, have made up most of the turtle deaths in the gulf so far.  André M. Landry Jr. of the Sea Turtle and Fisheries Ecology Research Laboratory at Texas A&M University, Galveston, said satellite radios had been attached to several sea turtles, including Thelma, for research. He hopes these will offer clues about what is happening offshore.

“If she is beached, it is going to be constantly sending out a signal as opposed to the random signals they send out when they randomly come up to breathe,” Dr. Landry said.

Barbara Schroeder, national turtle coordinator for NOAA fisheries, the government agency charged with assessing damage to offshore life, said that the agency was investigating the sea turtle deaths intensively, but did not have many answers yet.
She said that so far full necropsies had been performed on 50 turtles and partial necropsies on another 17. Internal inspections of the animals, she said, did not reveal oil. But she added that scientists still had to test tissue samples taken from some of the turtles for evidence of oil.

She cautioned that it might be hard to determine conclusively how the turtles died or even how the spill was affecting the species more generally.

“People think this is like television, where the mystery is solved in one hour,” she said. “It is very complex. Most of the impacts occurring to turtles are out of sight. Most turtles never wash ashore.”

The Kemp’s ridley is millions of years old; its ancestors once swam with dinosaurs. Sandy olive in color, Kemp’s ridleys are the smallest of the sea turtles, only about two feet across. Although the turtles have been spotted along the Atlantic Seaboard, they return to the warm waters of the gulf to breed.

As recently as the 1940s, they were abundant in the Mexican gulf waters. Tens of thousands at a time would come ashore on the same day at Rancho Nuevo, a remote Mexican beach in Tamaulipas State, to lay their eggs in the synchronized pattern unique to their breed. But pollution, the collection of eggs for food and aphrodisiacs and the nets of shrimp trawlers depleted their numbers.

Then came the blowout on the Ixtoc 1. The deepwater well dumped three million barrels of crude into the gulf, covering the beach at Rancho Nuevo. Nine thousand hatchlings had to be airlifted to nearby beaches. Although the role of the oil in killing the turtles was never confirmed, by 1985, there were fewer than 1,000 Kemp’s ridleys left.

To prevent a single environmental catastrophe from sending the turtles into extinction, eggs from remaining turtles, including an egg that became sea turtle No. 15, were brought here to Padre Island to begin a new colony. She came in 1986.
At birth, the babies were set free in the surf down the road from the ranger station to allow them to imprint the beach on their memories, then captured again and protected until they were nine months old and less susceptible to becoming prey.
“We called it head start, after the school program,” said Donna J. Shaver, chief of sea turtle science and recovery for the National Park Service at Padre Island, who has worked with the sea turtles there since 1980.

No. 15 has returned to the island six times to lay clutches of eggs, burying her most recent round of 92 eggs in the sand by an enormous rusted, beached buoy only one and a half miles from where she was first put into the surf 24 years ago.


Last edited on Thu May 20th, 2010 07:02 pm by sydneyst

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 Posted: Wed May 19th, 2010 12:23 am

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Oil Reaches South Pass in Mississippi Delta
Beaches and Wetlands Fouled
Greenpeace Photodocuments Effects




Greenpeace photostream
http://www.flickr.com/photos/greenpeaceusa09/page2/

May 16, 2010
rights reserved to Greenpeace























View of Washington DC All rights reserved



Fort Jackson, Louisiana (USA).
May 15th, 2010.



Fort Jackson, Louisiana (USA). May 15th, 2010. Veterinarian Erica Miller, left, of the International Bird Rescue Center





Pelican From BP Oil 
Fort Jackson, Louisiana (USA). May 15th, 2010.








Interior Secretary Watches Bird Cleaning Salazar Looks On As Bird Is Cleaned in Gulf US Interior Secretary at Bird Rescue Center in the Gulf Region

 
Fort Jackson, Louisiana (USA).
May 15th, 2010. Interior Secretary Ken Salazar looks on.
 All rights reserved


Fort Jackson, Louisiana (USA). May 15th, 2010. The Secretary of the Interior Ken Salazar looks on.
rights reserved



Fort Jackson, Louisiana (USA). May 15th, 2010. The Secretary of the Interior Ken Salazar visits the


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 Posted: Tue May 18th, 2010 01:22 am

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Do Dispersants Only Worsen the Problem?
Australian Government Replies That Situationally They Help


http://www.amsa.gov.au/Marine_Environment_Protection/National_plan/General_Information/Dispersants_Information/FAQ_Oil_Spills_Dispersants.asp

Protect Birds, Sensitive Wetlands, Potentially Lethal to fish Larvae

excerpts on ecotoxicology:

1. Are chemical dispersants toxic to marine life ?

 
For the majority of laboratory tests the Australian approved Oil Spill Dispersants rate predominantly as "slightly toxic" to "practically non-toxic" by the International Maritime Organization/GESAMP classification system. (Sydney: note that this list includes Corexit, the dispersant primarily used in the Gulf).

All dispersants approved for use within Australian waters must pass laboratory acute toxicity testing requirements for two temperate and two tropical marine species as specified by the National Plan protocol.

The toxicity of dispersed oil is primarily due to the toxic components of the oil itself. Many laboratory studies on a range of test species have confirmed the fact that "the acute toxicity of dispersed oil generally does not reside in the dispersant but in the more toxic fractions of the oil".

The toxicity of Oil Spill Dispersants to aquatic organisms under laboratory conditions appears to relate primarily to the chemical composition of the individual dispersant.
At the application rates used in (most) oil spill incidents, and mixing conditions of the ocean, Oil Spill Dispersants would not, in most circumstances, be toxic to marine organisms.

National Plan Guidelines for Acceptance of Oil Spill Dispersants).
At present ten oil spill dispersants have been approved under the National Plan guidelines. Their "Trade Names" are listed below:

  • Tergo R-40
  • Ardrox 6120
  • BP-AB
  • Corexit 9500
  • Corexit 9527
  • Corexit 9550
  • Shell VDC
  • Shell VDC+
  • Slickgone NS
  • Slickgone LTSW.

  • 2. What are the negative effects of dispersants on the environment ?

    The acute toxicity of dispersed oil generally does not reside in the dispersant but in the more toxic fractions of the oil. Dispersing oil into the water in situations where there is little water movement or exchange, such as shallow embayments, increases exposure of subsurface, benthic organisms and fish to the toxic components of the oil.

    Fish and other marine life in the larvae stage or juvenile stages are more prone to the toxicity effects of oil and dispersants. Therefore it is unlikely dispersants will be used near commercial fisheries, important breeding grounds, fish nurseries, shellfish aquaculture etc. unless it is to protect a more important environmental resource.
    Seagrasses and coral reef communities are particularly sensitive to dispersed oil because instead of the oil "floating over" the reefs and submerged seagrass beds the oil/dispersant mixture in the water colour will come into direct contact with these sensitive ecosystems.

    Generally there is a reluctance by spill responders to use dispersants in shallow waters less than 5 metres deep, although there may be situations where using dispersants could save foreshore impacts or wildlife.

    3. What are the impacts of dispersed oil on coral reefs? Coral reef communities are highly sensitive to both oil and oil/dispersant mixtures. For example the exposure of coral to hydrocarbons can cause:

  • loss of symbiotic zooxanthellae (tiny algae living in coral),
  • reduced metabolism,
  • cellular atrophy,
  • decreased reproductive success,
  • impaired tissue development, and
  • death of the coral.

  • Spill responders will avoid using Oil Spill Dispersants in or near coral reefs, in shallow waters, sea grass beds or where poor water exchange or circulation is apparent, unless in exceptional circumstances to protect mangroves or other highly sensitive foreshores.

    Last edited on Tue May 18th, 2010 01:49 am by sydneyst

    sydneyst
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     Posted: Tue May 18th, 2010 12:50 am

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    Less Toxic Dispersants Lose Out in BP Oil Spill Cleanup
     
    http://www.nytimes.com/gwire/2010/05/13/13greenwire-less-toxic-dispersants-lose-out-in-bp-oil-spil-81183.html

    http://www.scientificamerican.com/article.cfm?id=the-science-of-dispersants

    http://www.nap.edu/catalog.php?record_id=11283

    http://www.amsa.gov.au/Marine_Environment_Protection/National_plan/General_Information/Dispersants_Information/FAQ_Oil_Spills_Dispersants.asp

    After the Deepwater Horizon rig exploded and a deepwater well began gushing crude in the Gulf of Mexico three weeks ago, BP quickly marshaled a third of the world's available supply of dispersants, chemicals that break surface oil slicks into microscopic droplets that can sink into the sea.

    But the benefits of keeping some oil out of beaches and wetlands carry uncertain costs. Scientists warn that the dispersed oil, as well as the dispersants themselves, might cause long-term harm to marine life.

    So far, BP has told federal agencies that it has applied more than 400,000 gallons of a dispersant sold under the trade name Corexit and manufactured by Nalco Co., a company that was once part of Exxon Mobil Corp. and whose current leadership includes executives at both BP and Exxon. And another 805,000 gallons of Corexit are on order, the company said, with the possibility that hundreds of thousands of more gallons may be needed if the well continues spewing oil for weeks or months.

    But according to EPA data, Corexit ranks far above dispersants made by competitors in toxicity and far below them in effectiveness in handling southern Louisiana crude.  Of 18 dispersants whose use EPA has approved, 12 were found to be more effective on southern Louisiana crude than Corexit, EPA data show. Two of the 12 were found to be 100 percent effective on Gulf of Mexico crude, while the two Corexit products rated 56 percent and 63 percent effective, respectively. The toxicity of the 12 was shown to be either comparable to the Corexit line or, in some cases, 10 or 20 times less, according to EPA.

    EPA has not taken a stance on whether one dispersant should be used over another, leaving that up to BP. All the company is required to do is to choose an EPA-approved chemical, EPA Administrator Lisa Jackson told reporters yesterday during a conference call aimed at addressing questions about dispersants being used in efforts to contain the Gulf spill.

    "Our regular responsibilities say, if it's on the list and they want to use it, then they are preauthorized to do so," Jackson said.

    One explanation for BP's reliance on Nalco's Corexit, which its competitors say dominates the niche market for dispersants because of its industry ties, was its availability in large quantities at the time of the Gulf spill.

    "Obviously, logistics and stockpiles and the ability for the responsible party to pull the materials together," Jackson said. "I'm sure that has a lot to do with the ones that they choose."

    Nonetheless, experts question BP's sustained commitment to Corexit, given apparently superior alternatives.

    "Why wouldn't you go for the lesser toxic formulation?" said Carys Mitchelmore, an assistant professor of environmental chemistry and toxicology at the University of Maryland's Center for Environmental Science. Mitchelmore testified on Capitol Hill this week about dispersants and co-authored a 2005 National Academy of Sciences report on the chemicals.

    ...Critics say Nalco, a joint partnership with Exxon Chemical that was spun off in the 1990s, boasts oil-industry insiders on its board of directors and among its executives, including an 11-year board member at BP and a top Exxon executive who spent 43 years with the oil giant.

    "It's a chemical that the oil industry makes to sell to itself, basically," said Richard Charter, a senior policy adviser for Defenders of Wildlife.

    The older of the two Corexit products that BP has used in the Gulf spill, Corexit 9527, was also sprayed in 1989 on the 11-million-gallon slick created by the Exxon Valdez grounding in Alaska's Prince William Sound.

    Cleanup workers suffered health problems afterward, including blood in their urine and assorted kidney and liver disorders. Some health problems were blamed on the chemical 2-butoxyethanol, an ingredient discontinued in the latest version of Corexit, Corexit 9500, whose production Nalco officials say has been ramped up in response to the Gulf of Mexico disaster.

    Among Corexit's competitors, a product called Dispersit far outpaced Corexit 9500, EPA test results show, rating nearly twice as effective and between half and a third as toxic, based on two tests performed on fish and shrimp.

    Bruce Gebhardt, president of the company that manufactures Dispersit, U.S. Polychemical Corp., said BP asked for samples of his company's product two weeks ago. Later, he said, BP officials told him that EPA had wanted to ensure they had "crossed all their T's and dotted all their I's" before moving forward.

    Gebhardt says he could make 60,000 gallons a day of Dispersit to meet the needs of spill-containment efforts. Dispersit was formulated to outperform Corexit and got EPA approval 10 years ago, he said, but the dispersant has failed to grab market share from its larger rival.

    "When we came out with a safer product, we thought people would jump on board," he said. "That's not the case. We were never able to move anyone of any size off the Corexit product."

    He added, "We're just up against a giant."

    Last edited on Tue May 18th, 2010 01:20 am by sydneyst

    sydneyst
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     Posted: Mon May 17th, 2010 03:47 pm

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    Kemp Ridley Hatching Numbers for Texas Coast
                                                     1996-2009

    http://www.nps.gov/pais/naturescience/strp.htm

    More Kemp's ridley nests are recorded at Padre Island National Seashore than at any other location in the U.S., making it the most important Kemp’s ridley nesting beach in the U.S. (Shaver, 2005).

    In 1996, two Kemp's ridley sea turtles with living tags came ashore and laid eggs at Padre Island National Seashore. These were the first recorded returnees from the 1978-1988 project. One of the turtles had been hatched in 1983 and the other in 1986. During nearly every year since 1996, a few turtles from this project have been found nesting. However, most of the turtles nesting in Texas today are from the wild stock. In 2009, 197 Kemp's ridley nests were located in Texas, including 117 at Padre Island National Seashore.

    Nesting by Kemp's ridleys has increased on the Texas coast in recent years. The annual numbers of nests and eggs documented, and hatchlings released on the Texas coast since 1996 are shown in the table below (Shaver, 2005, unpublished data).
     
    Kemp’s ridley nests documented on the Texas coast since 1996


    a) Of the 195 nests discovered, 185 of the nests kept in protected incubation contained 17,958 unbroken eggs (25 were broken). An additional unknown quantity of eggs were in the 10 nests that incubated on the beach. Over half of these in situ nests were predated and accurate egg counts could not be made.
    b) Overall, 15,819 hatchlings were released and successfully entered the water from the 185 nests in protected incubation. An additional unknown quantity were released from 10 nests that incubated unprotected on the beach (two of which failed to hatch).
    c) Of the 197 nests discovered, 186 of the nests kept in protected incubation contained 17,507 unbroken eggs (11 were broken). An additional unknown quantity of eggs were in the 11 nests that incubated on the beach. Over half of these in situ nests were predated and accurate egg counts could not be made.
    d) Overall, 14,506 hatchlings were released and successfully entered the water from the 186 nests in protected incubation. An additional unknown quantity were released from 11 nests that incubated unprotected on the beach.

    Attached Image (viewed 1255 times):

    hatchlingpadre.jpg

    Last edited on Mon May 17th, 2010 04:22 pm by sydneyst

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     Posted: Mon May 17th, 2010 08:16 am

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    Powerful 60 Minutes Special Investigates Blow-out

    May 16,2010

    http://www.cbsnews.com/video/watch/?id=6490140n&tag=contentBody;housing
     
    Scott Pelley interviews Mike Williams, a survivor who tells of his improbable escape and the critical  decisions leading up to the blow-out that appeared to be based on speed and profit-making rather than safety.  A leading U Cal expert on blow-outs assesses the evidence.

    excerpts from transcript:

    But while it was shut tight, a crewman on deck accidentally nudged a joystick, applying hundreds of thousands of pounds of force, and moving 15 feet of drill pipe through the closed blowout preventer.

    Later, a man monitoring drilling fluid rising to the top made a troubling find
    (WILLIAMS) He discovered chunks of rubber in the drilling fluid.



    Mike Williams

    And, Williams says, he knew about another problem with the blowout preventer.
    The bop is operated from the surface by wires connected to two control pods. One is a back-up. Williams says one pod lost some of its function weeks before. Transocean tells us the bop was tested by remote control after these incidents and passed. But nearly a mile below, there was no way to know how much damage there was or whether the pod was unreliable.

    In the hours before the disaster, Deepwater Horizon’s work was nearly done. All that was left was to seal the well closed. The oil would be pumped out by another rig later. Williams says, that during a safety meeting, the manager for the rig owner, transocean, was explaining how they were going to close the well when the manager from BP interrupted.

    (WILLIAMS) I had the BP company man sitting directly beside me. And he literally perked up and said “Well my process is different. And I think we’re going to do it this way.”

    And they kind of lined out how he thought it should go that day.
    So there was short of a chest-bumping kind of deal. The communication seemed to break down as to who was ultimately in charge.

    The day of the accident, BP flew several managers to the Deep Water Horizon for a ceremony to congratulate the crew for seven years without an injury.
    While they where there, a surge of explosive gas came flying up the well from three miles below.

    The rig’s diesel engines which power its electric generators sucked in the gas and began to run wild.

    (WILLIAMS) I’m hearing hissing. Engines are over-revving. And then all of a sudden, all the lights in my shop just started getting brighter and brighter and brighter. And I knew then, we were, something bad was getting ready to happen.

    Read more:


     http://www.sunherald.com/2010/05/16/2185053_p3/60-minutes-transcript-from-blowout.html#ixzz0oAYhKo3T


     

    Last edited on Mon May 17th, 2010 08:35 am by sydneyst

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     Posted: Sun May 16th, 2010 10:24 pm

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    Partial Lists Available Identifying Turtle Habitat in Path of Spill

    No composite map seems available for all the beach nests and habitat of the potentially affected turtle species.  Nevertheless, some localized maps or lists providing nest locations are available:

    http://www.seaturtle.org/tracking/?project_id=495
    2010 tracking information
    A project of Padre Island National Seashore Kemp's Ridley Tracking Program in conjunction with the partners and sponsors detailed below.

    Subscribe to receive daily project updates

    Padre Island National Seashore Kemp's Ridley Tracking - 2010

     Name                   Species           Life Stage    Release Date    Last Location     Days Transmitted

    47519 (YYA949)Kemp's Ridley  adult           2010-04-29      2010-05-1617
    47529 (YYA504)Kemp's Ridley  Adult           2010-05-06      2010-05-159
    47562 (YYA562)Kemp's Ridley  Adult           2010-05-06      2010-05-159
    47690 (YYA155)Kemp's Ridley  Adult           2010-05-11      2010-05-154

    Click on an animal's name for maps and more information.


    http://texasturtlenest.blogspot.com/


    In 2009, a midyear census tallied 181 Kemp's ridley nests on the Texas coast including (north to south in state):

    Bolivar Peninsula 1
    Galveston Island 3
    Brazoria County, north of Surfside 3
    Surfside Beach 0
    Quintana Beach 1
    Bryan Beach 2
    San Bernard Wildlife Refuge 1
    Sargent Beach 1
    Matagorda Peninsula 3
    Matagorda Island 7
    San Jose Island 4
    Mustang Island 2
    Corpus Christi Bay 1
    North Padre Island 116, including 109 at Padre Island National Seashore
    South Padre Island 27
    Boca Chica Beach 9

    Seaturtle.org provides a map of recent sitings of sea turtles in the gulf but the information is  not current:
     
    http://www.seaturtle.org/istor/map.php

    more general information on Kemp's Ridley turtles:

    http://www.nmfs.noaa.gov/pr/species/turtles/kempsridley.htm

    Other links:

    http://en.wikipedia.org/wiki/Green_turtle



    NPS Photo
    Kemp's ridley hatchling

    Here are links to some important information on sea turtles, life history and habitat:

    Green Sea Turtle
    Hawksbill Sea Turtle
    Kemp's Ridley Sea Turtle
    Leatherback Sea Turtle
    Loggerhead Sea Turtle
     
    Current Information and Reporting
    Current Sea Turtle Nesting Season
    Hatchling Sea Turtle Releases
    Look for and Report Sea Turtles Nesting
    Look for and Report Stranded Sea Turtles
    Texas Area Contacts to Report Nesting and Stranded Sea Turtles
     
    Sea Turtle Research and Conservation
    Sea Turtle Science and Recovery Overview
    Sea Turtle Research, Conservation, and Monitoring Partners
    Kemp's Ridley Sea Turtle Recovery Project
    Sea Turtle Stranding and Salvage Network
    Satellite Tracking of Nesting Kemp's Ridley Sea Turtles

    Satellite Tracking of Adult Male Kemp's Ridley Sea Turtles
    Netting, Satellite Tracking, and Strandings of Green Sea Turtles
     
    Other Related Information
    Media Coverage
    Community Support
    Trained Dog to Help Locate Nests
    Habits of Nesting Kemp's Ridley Turtles
    Habits of Emerging Kemp's Ridley Hatchlings

    Last edited on Sun May 16th, 2010 11:46 pm by sydneyst

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     Posted: Sun May 16th, 2010 07:36 pm

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    Another Snag Hits As Oil Plumes Form Under Water
    by NPR Staff and Wires
    May 16

    May 16, 2010
    BP officials say they were on the verge of a breakthrough stemming the gushing oil leak in the Gulf of Mexico, but another accident has set them back. Meanwhile, scientists have found huge plumes of oil lurking under the surface of the water.

    Officials say they successfully inserted a new pipe into the broken pipe spewing oil into the Gulf. That new pipe started sending oil to a ship on the surface, but, just moments later, two remotely-operated robots crashed into each other and knocked the pipes partially apart. The robots were taking photos of the operation.

    Heard On 'All Things Considered' May 15, 2010

    BP spokesman Glenn DaGian says engineers estimate it will take about nine hours to fix the problem. Despite the debacle, he says, BP was able to prove that their latest effort to fix the well was working — however briefly.

    At least 210,000 gallons of oil a day has gushed into the Gulf of Mexico since an oil rig exploded April 20 and sank two days later. Eleven people were killed in the blast.
    Researchers from the National Institute for Undersea Science and Technology say they have detected large oil plumes from just beneath the surface of the sea to more than 4,000 feet deep.

    Three or four large plumes have been found, at least one that is 10 miles long and a mile wide, said Samantha Joye, a marine science professor at the University of Georgia.

    Researchers Vernon Asper and Arne Dierks said in Web posts that the plumes were "perhaps due to the deep injection of dispersants which BP has stated that they are conducting."

    These researchers were also testing the effects of large amounts of subsea oil on oxygen levels in the water. The oil can deplete oxygen in the water, harming plankton and other tiny creatures that serve as food for a wide variety of sea critters.
    Oxygen levels in some areas have dropped 30 percent, and should continue to drop, Joye said.

    "It could take years, possibly decades, for the system to recover from an infusion of this quantity of oil and gas," Joye said. "We've never seen anything like this before. It's impossible to fathom the impact."

    Joye's lab was waiting for the research boat to return so a team of scientists can test about 75 water samples and 100 sediment samples gathered during the voyage. Researchers plan to go back out in about a month and sample the same areas to see if oil and oxygen levels have worsened.

    One expert said BP's latest idea seems to have the best chance for success so far. Inserting a pipe into the oil gusher would be easy at the surface, said Ed Overton, a LSU professor of environmental studies. But using robots in 5,000 feet (1,500 meters) of water with oil rushing out of the pipe makes things much more difficult.

    "It's something like threading the eye of a needle. But that can be tough to do up here. And you can imagine how hard it would be to do it down there with a robot," Overton said.

    The tube could capture more than three-quarters of the leak. BP also must contend with a smaller leak that's farther away. A week ago, the company tried to put a massive box over the main leak, but icelike crystals formed and BP scrapped that plan.
    n, and Melinda Deslatte in Baton Rouge, Louisiana, contributed to this report.

    Last edited on Sun May 16th, 2010 11:56 pm by sydneyst

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     Posted: Sun May 16th, 2010 12:54 pm

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    Studies Review Historical Evidence Regarding
    Biodegradation of Oil in Seawater


    http://www.offshore-environment.com/oil.html
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC281502
    /pdf/microrev00009-0186.pdf
    http://www.sciencedaily.com/releases/2005/05/050517063708.htm

    Temperature, Pressure, Oil Chemistry, Weathering, Available Nutrients and Bacteria Type Affect Breakdown
     
    excerpts:

    Complex processes of oil transformation in the marine environment start developing from the first seconds of oil's contact with seawater. The progression, duration, and result of these transformations depend on the properties and composition of the oil itself, parameters of the actual oil spill, and environmental conditions...


    Biosedimentation Effects

    Simultaneously, the process of biosedimentation happens. Plankton filtrators and other organisms absorb the emulsified oil. They sediment it to the bottom with their metabolites and remainders. The suspended forms of oil and its components undergo intense chemical and biological (microbial in particular) decomposition in the water column. However, this situation radically changes when the suspended oil reaches the sea bottom.

    Numerous experimental and field studies show that the decomposition rate of the oil buried on the bottom abruptly drops. The oxidation processes slow down, especially under anaerobic conditions in the bottom environment. The heavy oil fractions accumulated inside the sediments can be preserved for many months and even years...

    Microbial degradation.
    After a spill, hydrocarbons are subjected to physicochemical processes such as evaporation or photochemical oxidation which produce changes in oil composition. But the most important process acting on the spilled oil is biodegradation.

    It is well established that most crude oils are biodegradable to a great extent, especially components as short linear alkanes or simple aromatic hydrocarbons. However, the heavy fraction, made of long-chain saturated and polyaromatic hydrocarbons and a considerable fraction of asphaltenes and resins, is generally recalcitrant to degradation.

    The most important environmental factors that influence hydrocarbon biodegradation include temperature, concentration of nutrients and oxygen, and, of course, species composition and abundance of oil-degrading microorganisms. These complex and interconnected factors ...make interpreting and comparing available data about the rates and scale of oil biodegradation in the marine environment extremely difficult...

    ...About a hundred known species of bacteria and fungi are able to use oil components to sustain their growth and metabolism. In pristine areas, their proportions usually do not exceed 0.1-1.0% of the total abundance of heterotrophic bacterial communities. In areas polluted by oil, however, this portion increases to 1-10% [Atlas, 1993].


    Historical Spills and Evidence

    The spill of the supertanker Amoco Cadiz in March 1978 resulted in the largest oil spill to that date. In excess of 190,000 metric tons of oil was released into the marine environment during 2 weeks. A variety of intertidal sites off the Brittany coast was affected. Aminot (3) examined the fate of the oil in the water column before reaching the shoreline. He found a depletion of N, P, and 02 in the water column beneath
    the oil, which apparently resulted from microbial degradation of petroleum hydrocarbons.

    The in situ deficits of N, P, and 02 converted to a hydrocarbon biodegradation rate of 0.03 mg of oil degraded per liter per day in the water column under the oil. Aminot estimated that 9,000 metric tons of oil was biodegraded in the water column during the 2 weeks following the spill.

    ...The magnitude of the Amoco Cadiz spill was surpassed by the spill from the IXTOC-I well blowout. In June 1979, oil began spilling into the Bay of Campeche, Gulf of Mexico. The oil flowed for 10 months before the well was capped. Some of the oil washed onto the coastal beaches of Texas, but for the most part the current carried the oil away from U.S. waters. The oil from the IXTOC-I well formed a mousse.

    Boehm and VOL. 45, 1981 MICROBIOL. REV. Fiest (45) found little evidence for biological weathering of the hydrocarbons in the mousse.

    Atlas and co-workers (22, 23) found that biodegradation of mousse was greatly restricted, probably due to nutrient limitations and limited surface area for microbial attack. During a 6-month laboratory incubation under simulated natural conditions, 2 to 5% of the mousse (73) was converted to CO2. Despite favorable temperatures and high populations of hydrocarbon utilizers in association with the mousse, changes in n-alkane/ isoprenoid ratios took months rather than days to weeks.

    The contribution of biodegradation to weathering of oil from the IXTOC-I well was notably slower and of less magnitude than was found for the Amoco Cadiz. Pfaender and co-workers (52, 219) examined the degradation of hydrocarbons within the water column affected by the IXTOC-I oil. They found relatively rapid turnover times for hydrocarbons which had become dissolved in the water column. Rates of degradation ranged from 0.01 to 44pug of aliphatic hydrocarbon respired per liter per h with turnover times of 30 to 266 h.


    Last edited on Sun May 16th, 2010 11:57 pm by sydneyst


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