# data[].attributes.attachment_link.readable_text
On 20 April, the Deepwater Horizon drilling rig exploded in the Gulf of Mexico, killing 11 workers and causing an oil spill that soon became the worst environmental disaster in US history.

Here is a chronology of events in the months since, as BP has struggled to stem the leak and oil has washed ashore along the Gulf Coast, from the fragile Louisiana wetlands to the white sand beaches of Florida.

19 September

The ruptured well is finally sealed and "effectively dead", says the top US federal official overseeing the disaster, Coast Guard Adm Thad Allen.

17 September

BP pumps cement to seal the damaged well after it was intercepted by a relief well.

8 September

In its own internal report into the Gulf of Mexico oil spill - the first to be published since the disaster - BP spreads the blame for the 11 April explosion and resulting leak.

In a 193-page report BP accepts responsibility in part for the disaster, but also blames other companies working on the well.
'Many failures' caused BP spill
5 September

Thad Allen, the US coastguard official overseeing the clean-up operation, says the BP oil well at the centre of the leak poses "no further risk" to the environment, despite the final stages of an operation to pump concrete into a relief well remaining unfinished.
BP well 'poses no further risk'
3 September

The blowout preventer that failed to stop the explosion on the Deepwater Horizon rig is removed from the stricken Gulf of Mexico oil well by BP. The 300-ton device will be examined as part of the inquiry into the leak of 206m gallons of oil into the Gulf.

Meanwhile, the cost of the oil spill has risen to $8bn (£5.2bn), BP says - a rise of some $2bn in the past month alone.
BP blowout preventer 'removed'
19 August

A study published in a leading scientific journal confirms the presence of a toxic chemical residue one kilometre below the surface of the Gulf of Mexico, but says it amounts to just 0.1% of the total amount spilled.
Oil leak leaves undersea residue
16 August

The US announces that future applications for deepwater offshore drilling will require an environmental assessment, ending a practice that allowed BP's Deepwater Horizon rig to drill with little scrutiny.

The White House said decision-making must be "fully informed" by knowledge of any potential environmental consequences.
US to require oil drilling review
9 August

BP announces that the total cost to it of the oil spill so far has reached $6.1bn (£3.8bn). The total includes the cost of the spill response, containment, relief well drilling, and cementing up of the damaged well.

It also includes grants to the Gulf states hit by the spill and $319m paid out in compensation to some of those affected by the spill.
BP oil spill costs pass $6bn mark BP deposits $3bn in relief fund
4 August

The US government says three-quarters of the oil spilled in the Gulf has been cleaned up or broken down by natural forces.

Meanwhile, BP reports "encouraging" progress with the "static kill" operation to plug the well with mud and seal it with cement.
Majority of BP spill 'dealt with' BP says 'static kill' successful
3 August

The US government says the oil spill is officially the biggest leak ever, with 4.9 million barrels of oil leaked before the well was capped last month. Scientists said only a fifth of the leaking oil - around 800,000 barrels - was captured during the clean-up operation.
BP gears up to halt 'worst spill'
2 August

The US Environmental Protection Agency says in a study the dispersant used after the spill is no more toxic than oil alone. There had been concerns raised by congressional investigators that dispersant may have been more widely used than the government ordered.
Oil dispersant 'not more toxic'
28 July

US scientists say the oil from the well has cleared from the sea surface faster than expected, 100 days after the disaster began.
Surface Gulf oil 'vanishing fast'
27 July

BP confirms that chief executive Tony Hayward will leave his post by mutual agreement in October, but he is likely to retain a position in the company. BP plans to nominate him as a non-executive director of its Russian joint venture, TNK-BP.

Mr Hayward's American colleague, Bob Dudley, who has taken charge of the clean-up operation, will replace him.

Meanwhile, the oil giant's second quarter earnings are published, showing losses of $17bn for the three months between April and June - a UK record.

The company says it has set aside $32.2bn (£20.8bn) to cover the costs linked to the Gulf of Mexico spill.
BP puts oil spill cost at $32.2bn
26 July

The BBC reveals that 53-year old BP chief executive Tony Hayward will receive a year's salary plus benefits, together worth more than £1m, when he steps down. He will also be entitled to draw an annual pension of £600,000 once he reaches the age of 55.
BP boss Hayward 'to stand down'
25 July

Ships involved in BP's effort to secure the blown-out oil well prepare to resume work after a tropical storm in the Gulf of Mexico weakened.

Coast Guard chief Adm Thad Allen says the storm put back efforts to drill a relief well by seven to 10 days.
Oil spill vessels return to site
The BBC learns that BP's chief executive Tony Hayward, who has faced widespread criticism over his handling of the spill, is negotiating the terms of his exit from his post.
BP boss Hayward 'negotiates exit'
22 July

Dozens of vessels, including the rig drilling a relief well to permanently block the damaged well, are ordered to leave the site as Tropical Storm Bonnie approaches. BP warns that the final operation to plug the well could be delayed by up to two weeks by the storm.

The capped well is to remain unmonitored for several days.

Meanwhile, BP says it has been given permission to prepare for a "static kill" - pumping mud into the top of the well through the new cap - a step viewed as an intermediate measure. The firm would need final approval from the US to carry it out.
Storm forces ships off spill site
19 July

Adm Allen tells BP he is concerned about a "detected seep" on the sea floor near the well and other "undetermined anomalies". He said that if methane was found to be seeping from the sea floor, oil might also be leaking.
BP oil cap 'closed for extra day'
15 July

With the new cap in place, BP says it has temporarily shut off the oil flow in order to test the integrity of the well.

President Barack Obama hails "a positive sign".
BP says oil has stopped leaking
14 July

Adm Thad Allen says a relief well, which officials and BP have said is the only way permanently to plug the well, has come within 5ft (1.5m) of the leaking well bore.

10 July

BP begins a bid to place a tighter-fitting cap atop the leaking wellhead. The company warns that oil will flow freely while the caps are being exchanged, but says it has brought in 400 oil-skimming ships to deal with the increased flow.

6 July

Oil from the spill reaches Texas, meaning it has affected all five US Gulf Coast states.

But officials said it was unclear if the oil had drifted hundreds of kilometres from the leak site to the Texas shore, or had fallen from ships taking part in the clean-up operation.
Gulf oil leak tar balls hit Texas
5 July

BP says the oil spill response has cost the company $3.12bn (£2bn), including the cost of containing the spill and cleaning up the oil, and the cost of drilling relief wells. The figure also includes $147m paid out in compensation to some of those affected by the spill.
BP oil spill costs pass $3bn mark
22 June

A federal judge blocks the Obama administration's six-month moratorium on deepwater oil drilling in the Gulf of Mexico, saying the ban cannot be justified.

The administration quickly issues another moratorium with revised terms.

Meanwhile, BP hands day-to-day control of the response to Bob Dudley, replacing Chief Executive Tony Hayward, who had been widely criticised for his insensitive remarks on the spill.
US Gulf oil drilling ban blocked
18 June

BP chief executive Tony Hayward receives a tongue-lashing at a hearing in the US Congress.

Henry Waxman, chairman of the House Committee on Energy and Commerce, says BP's "complacency" before the 20 April rig explosion was "astonishing".
Congress turns scorn on BP chief
17 June

BP announces it will place $20bn in a fund to compensate victims of the oil spill and says it will not pay a shareholder dividend this year.

15 June

President Obama addresses the nation from the Oval Office, vowing, "We will make BP pay for the damage their company has caused."
Oil spill: Obama to 'make BP pay'
14 June

President Obama makes a fourth trip to the gulf.

12 June

Responding to complaints in the British media of an anti-British tone to his remarks, President Barack Obama tells UK Prime Minister David Cameron that his criticism of BP has nothing to do with national identity.
Obama defends US criticism of BP
10 June

The US Geological Survey estimates the oil flow at as many as 40,000 barrels per day before a cap was put on the well on 3 June. BP announces it is collecting 15,800 barrels per day from the well.
BP spill 'double early estimates' Q&A: Scale of BP oil spill
8 June

Adm Thad Allen, the commander of the US response, says clean-up of the oil-stricken Gulf could take years.

Meanwhile, President Obama says he has been consulting with experts so he can learn "whose ass to kick" in the matter.

The US government says underwater oil plumes have travelled as far as 40 miles from the site of the leaking well.
US oil clean-up 'will take years' Underwater oil plumes 'spreading'
4 June

BP places a cap, called the "lower marine riser package", atop the leaking wellhead. The cap allows the company to pipe much of the oil and gas leaking from the well to ships on the surface.

President Obama takes a third trip to the region.
BP begins to funnel off oil spill
2 June

The US announces a criminal inquiry into the BP oil spill.
US begins criminal probe of spill
30 May

Carol Browner, President Barack Obama's adviser on energy policy, says the spill is the worst environmental disaster in US history, worse even than the 1989 Exxon Valdez spill in Alaska.
Spill 'is worst US eco-disaster'
28 May

Obama visits the Gulf Coast again and declares "the buck stops with me".

26 May

BP prepares to plug the leaking well with heavy drilling mud, a procedure called a "top kill". The attempt is declared a failure three days later.
What is a 'top kill'?
19 May

Oceanographers say oil from the leak has entered an ocean current - the "loop current" - that could carry it towards Florida and potentially up the US east coast.
Gulf oil 'reaches major current'
14 May

Researchers who have analysed underwater video from the leak site estimate as many as 70,000 barrels of oil are leaking into the Gulf per day, with a margin of error of plus or minus 20%, significantly higher than earlier estimates.

BP tries to thread a tube into the broken wellhead in an effort to collect some of the leaking oil in surface ships.

Meanwhile, President Obama condemns the "ridiculous spectacle" of the companies trading blame while oil spews from the well.
Fresh BP effort to stop oil leak
11 May

At a series of congressional hearings, BP, Transocean and Halliburton, the three companies involved in the Deepwater Horizon drilling operations, all blame each other for the disaster.

10 May

BP officials weigh shoving debris, including golf balls and rubber tyres, into the leaking wellhead, a manoeuvre known as the "junk shot". They also ready a "top hat" - a metal dome - to be placed over the leak.

Meanwhile, BP reveals the oil spill has cost the company $350m (£233m) so far.
BP 'may stem oil with golf balls'
8 May

BP's effort to place a giant metal box atop the leaking well to contain the spill fails when ice crystals accumulate inside the box and engineers are forced to remove it.

Meanwhile, officials revise the estimate of the leak's rate upward to 5,000 barrels per day.
Setback in US oil containment bid
2 May

President Obama makes his first trip to the Gulf Coast and says BP is responsible for the leak and for paying for its clean-up.

"We're dealing with a massive and potentially unprecedented environmental disaster," he says.

"The oil that is still leaking from the well could seriously damage the economy and the environment of our Gulf states. And it could extend for a long time. It could jeopardise the livelihoods of thousands of Americans who call this place home."
Obama's sombre oil leak prognosis
30 April

Oil from the leaking well begins washing ashore in Louisiana. Soon fragile coastal wetlands are inundated with thick, brown mud.

President Barack Obama's administration bans oil drilling in new areas off the US coast pending investigations into the cause of the BP spill. Before the spill, Mr Obama had said he would allow new offshore drilling.
Oil 'reaches' coast in US spill
29 April

The US Coast Guard sets fire to patches of spilled oil in an effort to prevent the slick from reaching the vulnerable Louisiana coastal wetlands.

President Barack Obama pledges "every single available resource", including the military, to help in the response effort.
US sets fire to oil slick in Gulf
28 April

The US Coast Guard warns the oil leak could become the worst oil spill in US history.
Growing concerns over US oil leak
26 April

In a reverse, officials reveal the well is leaking an estimated 1,000 barrels of oil per day and warn of environmental disaster.

Meanwhile, BP sends undersea robots to the wellhead in an unsuccessful effort to activate the blowout preventer, a piece of heavy kit mounted on top of the well to stem the flow of oil.
Environmental fears over US spill
23 April

The Coast Guard says it had no indication that oil was leaking from the well 5,000ft below the surface of the Gulf.
US fears ease over oil rig spill
22 April

The Deepwater Horizon sinks to the bottom of the Gulf after burning for 36 hours, raising concerns of a catastrophic oil spill.

A Coast Guard official says the Macondo well, which the rig had been drilling, could be releasing up to 8,000 barrels of oil per day.

20 April

An explosion aboard the Deepwater Horizon drilling rig in the Gulf of Mexico, 52 miles (84km) south-east of Venice, Louisiana, kills 11 workers. Operator Transocean, under contract for BP, says it had no warning of trouble ahead of the blast.

The rig was drilling in about 5,000ft (1,525m) of water, pushing the boundaries of deepwater drilling technology.

# data[].attributes.attachment_link.description
On 20 April, the Deepwater Horizon drilling rig exploded in the Gulf of Mexico, killing 11 workers and causing an oil spill that soon became the worst environmental disaster in US history.

# data[].attributes.attachment_link.readable_text
A lot of things have gone wrong in the last 72 days since oil started spilling into the Gulf, and very few things have gone right. Unfortunately, the oil spilling into the Gulf is only one of many, many problems in the Gulf. There are the obvious problems of extremely polluted water, the oil soaked animals, the oil soaked beaches, the loss of tourism, the loss of jobs, and the loss of faith in the process that is supposed to ensure things like this never happen. But, why hasn't the oil been cleaned up? Why is the leak still spewing oil into the Gulf? BP has their fair share of blame, but so does the federal government.

The government has had a lot of missteps. The EPA would not allow ships to skim oil from the water because they couldn't get 100% of the oil out. They could only get 99% of the oil out. They failed to get rid of the horribly outdated Jones Act that forbids foreign vessels from helping us clean up the gulf. There have been plenty of problems with the way the Federal Government has reacted to the oil spill, but it's never too late to start getting it right.

The Heritage Foundation has put together a list of things the Obama administration can do to mitigate the damage that the oil slick can still do. These are steps that can be taken immediately, and more items will be added to the list when appropriate. Simple things like waiving the Jones Act (as the Bush Administration did during Katrina), or accepting international assistance. Or allowing ships like the S.S. A-Whale-that has the capability to skim 500,000 barrels a day- to immediately start assisting efforts. It's in the Gulf now, but it is still not being used.

One thing they should not do is halt the exploration for oil. The economy of the gulf relies heavily on oil exploration and The Heritage Foundation recommends President Obama end the moratorium on drilling. It is a knee-jerk reaction that has devastating long-term consequences. The list also calls for common sense solutions like not cutting the Coast Guard's budget, and temporarily waiving EPA regulations that make no sense in these desperate times.

The Heritage Foundation's list includes other things that should be done and it will be updated as items get completed. Read it here, and check back often, as they keep the administration accountable to the crisis he needs to lead us through.

# data[].attributes.attachment_link.title
Cleaning Up Obama's Mess in the Gulf - Breitbart

# data[].attributes.attachment_link.description
A lot of things have gone wrong in the last 72 days since oil started spilling into the Gulf, and very few things have gone right. Unfortunately, the oil spilling into the Gulf is only one of many, many problems in the Gulf.

# data[].attributes.attachment_link.readable_text
On April 20, 2010, the Deepwater Horizon oil rig, owned by BP, exploded in the Gulf of Mexico. In addition to killing 11 crew members, it unleashed about 3.19 million barrels of oil a mile below the ocean surface over the course of 87 days before the leak could be contained.

Five years later, BP agreed to pay the US federal government and state governments of Florida, Louisiana, Alabama, Mississippi, and Texas a total of $18.7 billion for damages. They paid billions more in criminal charge penalties (including for 12 felonies for negligence and failure to disclose information to Congress) and payouts to private individuals. It was the largest settlement ever for a corporation, and perhaps rightly so for a disaster that has left the Gulf marine and coastline ecosystems in disarray.

But there is one silver lining: After the spill, BP executives recognized that they didn't have enough information about the environment in which they were extracting oil.

Never before had there been a spill of that magnitude in the Gulf of Mexico (the 1979 Ixtoc 1 spill only released about half as much oil), which made it difficult to truly assess how bad the damage was. So, in 2010 BP voluntarily committed to giving $500 million to a board of 20 independent researchers over the course of 10 years to provide BP with unbiased answers to all of their questions about the Gulf's marine environment. The Gulf of Mexico Research Initiative (GoMRI) was formed. (In similar fashion, ExxonMobil contracted scientists after their oil tanker crashed and spewed millions of gallons of oil off the coast of Alaska in 1989, although the effort wasn't as organized.)

Over the past seven years, GoMRI, chaired by oceanographer Rita Colwell (who is affiliated with both Johns Hopkins University and the University of Maryland and once directed the National Science Foundation) has allocated resources to projects ranging from understanding the physics of oil droplets spewing out of wells to figuring out how chemicals in oil change fish sex hormones. It also set aside some funding to figure out just what creatures live in the Gulf of Mexico anyway.

"So far we have identified over 60 species of fishes that have not been previously found in the Gulf, and of these at least seven are undescribed species," Tracey Sutton, an oceanographer at Nova Southeastern University working on GoMRI, said in an email. An "undescribed species" is one that's never been seen before, anywhere.

Scientists working on the project, called the Deepend Consortium, are sending nets down up to 1,500 meters (almost a mile) into the ocean and collecting the animals that get caught in them.

Heather Judkins, a biological oceanographer at the University of South Florida at St. Petersburg also working on the project, says they've found at least two entirely new species of squid, and another cephalopod previously thought only to live in other parts of the Atlantic ocean. She and her team still need to compare DNA sequences of the animals to existing animal genome databases to confirm that these animals are, in fact, novel. Although they look unique, they could be examples of previously known species with different physical characteristics.

Judkins points out that in some ways these discoveries are unsurprising, since 95% of the world's oceans are still unexplored. If scientists want to understand the damages the oil industry may cause to the deep ocean, they're going to have to get a baseline reading of life there first.

Although scientists are uncovering some new forms of life, even massive populations of these 60 new species would barely put a dent in all the marine life the oil spill definitively killed. Estimates suggest that 80,000 birds, 35,000 hatchling sea turtles, and over 500 million pounds of oysters were lost.

Most Popular

Read full story

# data[].attributes.attachment_link.keywords[]
Boats and boating--Equipment and supplies

# data[].attributes.attachment_link.title
The BP oil spill led scientists to discover 60 new animal species living in the Gulf of Mexico

# data[].attributes.attachment_link.description
On April 20, 2010, the Deepwater Horizon oil rig, owned by BP, exploded in the Gulf of Mexico. In addition to killing 11 crew members, it unleashed about 3.19 million barrels of oil a mile below the ocean surface over the course of 87 days before the leak could be contained.

# data[].attributes.attachment_link.readable_text
The Leak

4.9 million: Barrels of oil (205.8 million gallons) leaked from the Deepwater Horizon well, about half the amount of crude oil the U.S. imports per day

19: Times more oil leaked from Deepwater Horizon than spilled from the Exxon Valdez in 1989 (10.8 million gallons)

62,000: Barrels leaking per day when the wellhead first broke, roughly the amount of oil consumed in Delaware each day

53,000: Barrels leaking per day when the well was capped on July 15, roughly the amount of oil consumed in Rhode Island each day

397.7 million: Dollars' worth of the oil spilled at current market prices ($81.17 per barrel)

665: Miles of coastline contaminated by oil

The Cleanup

16.5 million: Gallons of oil chemically dispersed by National Incident Command

32.9 million: Gallons of oil naturally dispersed, which means it has broken into droplets smaller than the diameter of a human hair

51.5 million: Gallons of oil evaporated or dissolved. This differs from natural dispersion because instead of breaking down into small droplets, the oil breaks apart molecularly and dissolves into the water.

6.2 million: Gallons of oil skimmed off the Gulf by the more than 830 skimming vessels used in the response

35 million: Gallons directly recovered from the wellhead into ships through the riser pipe and top-hat systems

11.4 million: Gallons of oil has been removed by a series of 411 controlled burns

53.5 million: Gallons of oil still remaining in the water or washed ashore

95.6 million: Potential gallons of gasoline leaked from the wellhead (approximately 19.5 gallons of gas can be derived from one barrel of oil). That's about one-fourth of daily consumption in the United States.

10.4 million: Feet of sorbent boon (8.7 million) and containment boom (2.7 million) currently deployed to contain the oil

1.8 million: Gallons of both surface and subsea dispersant used by Unified Incident Command

28,900: Total number of personnel currently deployed in response to the spill. On July 8, 47,000 people had been deployed.

57,539: Square miles of Gulf waters that remain closed to fishing

In Perspective

184,181: Times you could drive a Toyota Prius (48 mpg highway) around the Earth at the equator using the lost oil

69,068: Times you could drive a Hummer H3 (18 mpg highway) around the Earth

311: Olympic-size swimming pools that could be filled with the oil that leaked from Deepwater Horizon

13,208: Homes that could have been heated for one year (approximately 2 gallons of heating oil are produced from one barrel, with an average American household using 742 gallons per year)
(Sources: Unified Incident Command (pdf), Energy Information Association and Fueleconomy.gov)

# data[].attributes.attachment_link.title
How Many Miles Could a Prius Drive on the Gulf's Spilled Oil?

# data[].attributes.attachment_link.description
4.9 million: Barrels of oil (205.8 million gallons) leaked from the Deepwater Horizon well, about half the amount of crude oil the U.S.

# data[].attributes.body
educational page

# data[].attributes.attachment_link.readable_text
Credit:

Terese Collins, On Wings Of Care

The Gulf oil spill is recognized as the worst oil spill in U.S. history. Within days of the April 20, 2010 explosion and sinking of the Deepwater Horizon oil rig in the Gulf of Mexico that killed 11 people, underwater cameras revealed the BP pipe was leaking oil and gas on the ocean floor about 42 miles off the coast of Louisiana. By the time the well was capped on July 15, 2010 ( 87 days later), an estimated 3.19 million barrels of oil had leaked into the Gulf.

The well was located over 5,000 feet beneath the water's surface in the vast frontier of the deep sea-a permanently dark environment, marked by constantly cold temperatures just above freezing and extremely high pressures. Scientists divide the ocean into at least three zones, and the deep ocean accounts for about three-quarters of Earth's total ocean volume.

Immediately after the explosion, workers from BP and Transocean (owner of the Deepwater Horizon rig), and many government agencies tried to control the spread of the oil to beaches and other coastal ecosystems using floating booms to contain surface oil and chemical oil dispersants to break it down underwater. Additionally, numerous scientists and researchers descended upon the Gulf region to gather data. Researchers are still trying to understand the spill and its impact on marine life, the Gulf coast, and human communities.

You can explore the spill in our interactive and read on for more information.

The Oil's Spread

Over the course of 87 days, the damaged Macondo wellhead, located around 5,000 feet beneath the ocean's surface, leaked an estimated 3.19 million barrels (over 130 million gallons) of oil into the Gulf of Mexico-making the spill the largest accidental ocean spill in history.

Once the oil left the well, it spread throughout the water column. Some floated to the ocean's surface to form oil slicks, which can spread more quickly by being pushed by winds. Some hovered suspended in the midwater after rising from the wellhead like a chimney and forming several layers of oil, dispersant and seawater mixtures drifting down current; during the spill a 22-mile long oil plume was reported. This plume formed because chemical dispersants, released into the water to break up the oil so it could wash away, allowed the oil to mix with seawater and stay suspended below the surface. And some oil sunk to the seafloor by gluing together falling particles in the water such as bacteria and phytoplankton to form marine snow. As much as 20 percent of the spilled oil may have ended up on top of and in the seafloor, damaging deep sea corals and potentially damaging other ecosystems that are unseen at the surface.

You can explore where the oil went in our interactive.

Clean-up Methods

When oil spills into the ocean, it is difficult to clean up. When you have 3.19 million barrels to clean up, it is even harder.

Part of the difficulty is that no two spills are alike. The amount and type of oil (whether crude or refined) affects how it spreads, and a spill in seawater spreads differently than freshwater. Local environmental conditions also play a huge role: currents, tides, weather, wind speed and direction, air temperature, water temperature and presence of ice all affect how the oil spreads and how well cleanup workers can access the spill area. This variability makes it difficult to plan for spills ahead of time.

The most basic method of clean up is to control the spread of the oil using physical barriers. When oil spills in water, it tends to float to the surface and spread out, forming a thin slick just a few millimeters thick. (A very thin slick is called a sheen, which often looks like a rainbow and can be seen in parking lots after a rainstorm.) Cleanup workers first surround the slick with floating booms to keep it from spreading to harbors, beaches or biologically important areas like marshes. Then they can use different tools to remove the collected oil. Often they will drive skimmers, boats that skim spilled water from the water's surface, through the slick.

After most of the oil is removed by skimmers, workers use sorbents to mop up the trace amounts left behind. Sorbents either absorb oil like a sponge or adsorb oil, which means that oil sticks to its surface. They come in three main types: natural organic materials like peat moss, straw, hay and sawdust; natural inorganic materials like clay, volcanic ash, sand, or vermiculite; and synthetic sorbents made of materials similar to plastic like polyurethane, polypropylene, and polyethylene. Which type is used will depend on the particular spill, as some types of sorbents work best on different types of oil and under different weather conditions.

Another option is to speed up the oil's natural biodegradation using dispersants. (See next section.)

Removing spilled oil from the environment is a difficult task. Because oil is hydrophobic (doesn't mix with water), it floats to the surface when it spills into the ocean and forms large slicks. These slicks can wreak havoc on coastal ecosystems and animals, so cleanup workers use dispersants -chemicals that break down the oil into smaller particles that mix with water more easily-to prevent them from forming. Evaporation and bacteria can then degrade these tiny droplets more quickly than if they were in a large slick, or waves can wash them away from the spill site.

Dispersants are often used when workers want to stop the slick from spreading to a protected area like a harbor or marsh. This can be a boon for animals found on the surface and coast, such as seabirds, marine mammals and those found in the Gulf's mangroves, because the oil is moved out of their habitat. But dispersants can also enter the food chain and potentially harm wildlife.

In the case of the Deepwater Horizon oil spill, clean-up workers treated the oil with over 1.4 million gallons of various chemical dispersants. Typically such large amounts are sprayed over the open ocean from an airplane or helicopter. But during the BP oil spill, they were also injected straight into the Macondo wellhead, the source of the leak, in order to reduce the amount of oil that reached the ocean surface. Five years after the spill some scientists believe that injecting dispersants directly at the wellhead may not have done much to help reduce the size of the oil droplets.

Just because the oil and dispersants are out of human sight and mind in the deep sea doesn't mean they're gone. It's possible that life in the deep sea was exposed to the dispersant-oil mixture. Scientists have found that the dispersant-oil mixture was rapidly colonized and broken down by bacteria that sunk towards the bottom. Any bits of the mixture that didn't get broken down would then get buried in coastal and deep-sea sediments, where its breakdown slows.

While the dispersant helps expose more of the oil to bacteria and waves which help to break it down, it also makes the oil more available to wildlife. One 2012 study showed that the combination of oil and the dispersant Corexit is 3 to 52-times more toxic to rotifers (microscopic animals) than oil by itself. This isn't because of anything inherently dangerous in the mixture of the two; the rotifers are more able to ingest oil once it's made accessible by the dispersant. Furthermore, the dispersants may not have been necessary. A modeling effort supported by the Gulf of Mexico Research Initiative offered evidence that the dispersants injected into the Macondo wellhead may not have helped to lessen the amount of oil reaching the surface after all.

A lot of research is still needed to fully understand the long-term effects of dispersants on the region and its inhabitants-not to mention how they move through the food chain to impact larger predators, such as people. Researchers are developing new dispersants that cause less environmental damage for the next spill. ( See "Human Health Impacts.")

Ecosystem Effects

There were some immediate impacts to the animals of the Gulf of Mexico that could be seen with the naked eye: pelicans black with oil, fish belly-up in brown sludge, smothered turtles washed up on beaches. But not much time has passed since the spill, and it will take many more years of monitoring and research to understand what happened.

Strandings of both dolphins and sea turtles increased significantly in the years following the spill. "From 2002 to 2009, the Gulf averaged 63 dolphin deaths a year. That rose to 125 in the seven months after the spill in 2010 and 335 in all of 2011, averaging more than 200 a year since April 2010," reported Reuters in 2015. Since then, dolphin deaths have declined, and long-term impacts on the population are not yet known. Kemp's ridley sea turtle nests have gone down in the years since the spill, and long-term effects are not yet known.

Seabirds were initially harmed by crude surface oil-even a small bit of oil on their feathers impeded their ability to fly, swim and find food by diving. Seabird losses may have numbered in the hundreds of thousands, but reliable estimates are hard to come by. Looking beyond the sea, researchers are currently studying how oil may have affected land birds that live in the marshes along the Gulf coast.

Invertebrates in the Gulf were hard hit by the Deepwater Horizon spill-both in coastal areas and in the deep. Shrimp fisheries were closed for much of the year following the spill, but these commercially-important species now seem to have recovered. Deep-water corals grow very slowly and can live for many centuries. Found as deep as 4,000 feet below the surface, corals near the blowout showed signs of tissue damage and were covered by an unknown brown substance, later identified as oil from the spill. Laboratory studies conducted with coral species showed that coral larva exposed to oil and dispersant had lower survival rates and difficulty settling on a hard surface to grow.

The impact of the spill on fish communities is still largely unknown. Lab studies have shown that oil can cause heart defects in the developing larvae of bluefin tuna and other fish, but we won't know if this occurred in the wild until after those larvae would have grown up. Some fish larvae populations actually grew after the spill, as they had more food in the form of oil-eating microbes.

There were some reports of deformed wildlife after the spill. For years following the spill there were reports of fish with lesions and deformities, and some reports of eyeless and deformed shrimp after the spill. However, consuming Gulf seafood is now completely safe.

Over 1,000 miles of shoreline on the Gulf of Mexico, from Texas to Florida, was impacted by oil from the Deepwater Horizon blowout. Much of this area has been cleaned, but eroded shorelines are taking longer to recover and erosion rates have accelerated in these areas.

You can explore more ecosystem effects in our interactive.

In May 2010, the Monterey Bay Aquarium Research Institute (MBARI) sent a high-tech robotic submersible to the oily waters of the Gulf of Mexico. Like other autonomous underwater vehicles (AUV), the robotic sub was programmed at the surface to navigate through the water on its own, collecting information on deep oil plumes from the Deepwater Horizon spill as it traveled. Although satellites and aircraft helped show the extent of the spill at the surface, researchers hoped that the AUV would allow them understand what was happening farther down in the water column.

During the NOAA-sponsored expedition, MBARI's AUV mapped part of a plume 1,000 meters (3,300 feet) below the surface, and collected water samples at various depths. The resulting data helped the researchers identify a persistent deep oil plume and link the oil in this plume to its source: the Deepwater Horizon blowout.

Once the over 200 million gallons of oil began spewing out of the damaged wellhead-where did it go? Keeping track of that much oil-especially as it sinks into the deep sea-is a difficult task that can't be done with eyes alone. Along with visual tracking, computer models of the oil's movement helped researchers get a better sense of what path it took and where it ended up.

To build the models, researchers first had to understand where ocean eddies, currents and waves carried the tiny oil particles. To understand surface water movement better, researchers set small, yellow boards made of wood afloat on the ocean's surface and asked beachgoers to report where they found these "drift cards" when they washed up on shore. This citizen scientist endeavor provided general information about how far the waves can carry a floating object and specific data points that can be used to improve models of where the oil disperses.

Further data collection has been ongoing since the spill by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). CARTHE has more high-tech "drift cards:" their "drifters" are small buoy-like instruments with GPS, which ping their locations to satellites as they drift on ocean currents. Their location gets tracked for weeks or months at a time and provide an unprecedented amount of location-based data for modeling. This information can be used to better predict oil movement in case of future spills.

After the Deepwater Horizon spill, oil was mixed throughout the ocean and made its way to coastal and deep-sea sediments. Researchers continue to collect samples from both the water and the sediment to determine if oil is present, and where exactly it came from. Chemical analysis of oil found after a spill can be used to determine its original source. In the case of Deepwater Horizon, tracking the origins of oil slicks that appeared after the well was capped proved helpful in determining if a new leak might have sprung.

About a month after the Deepwater Horizon oil spill (while the oil was still leaking out of the Macondo wellhead) BP announced that they would provide $500 million to fund an independent research program that would study the impacts of the spill on the environment and public health. With this funding, the Gulf of Mexico Research Initiative (GoMRI) was formed as a 10-year independent research program. The GoMRI research board, which is independent from BP, makes funding and research decisions, and as of early 2014 over $175 million has been distributed to research institutions, many of which are located in Gulf states.

At the outset, the twenty-person GoMRI board adopted five main research themes to focus on: physical movement of the oil and dispersant, degradation of the oil and its interaction with the ecosystem, environmental effects of the oil and dispersant, development of technology for improved response and remediation, and the effects of oil and dispersant on human health. GoMRI funded studies have examined where the oil went after the spill, and how the oil affected many types of marine life, including deep-sea coral ecosystems, seabirds, and jellyfish, to name just a few.

Read more about GoMRI research:

Collections

As scientists in the Gulf collect organisms potentially affected by the oil, they will need to compare them to animals from previous decades to identify how they have changed, if at all.

Here's where Smithsonian Collections can play a role. Soon after the Deepwater Horizon oil spill, Smithsonian Collections staff plotted invertebrate holdings from the Gulf onto Google Earth. Since 1979, invertebrate specimens have been deposited in the national collections of the National Museum of Natural History's Department of Invertebrate Zoology. In the Gulf of Mexico, more than 57,000 invertebrates (points on the map) from 5,789 distinct collecting sites from 14 Mineral Management Service survey programs (point colors) have been cataloged.

Following the Deepwater Horizon incident in late April 2010, collections staff updated the files to reflect the latest areas affected by the spill in real-time. "The points on the map represent less than half of our Gulf of Mexico holdings, the rest-approximately 75,000-still need to be processed and cataloged," said Bill Moser, museum specialist.

A Smithsonian study of a 1986 oil spill on the coast of Panama attracted renewed interest for its insights into the effects of oil spills on coastal systems. Working with the Smithsonian Tropical Research Institute, marine ecologist Dr. Jeremy Jackson and a team of researchers examined the spill's immediate and long-term effects on the coast in Bahia las Minas, Panama.

The benchmark study (PDF), published in 1989, documented the damage oil causes to coastal and tidal habitats. It's particularly notable because it includes 15 years of ecological data about the area before the spill collected by the Smithsonian. The affected area includes the Smithsonian biological reserve known as the Galeta Marine Laboratory. "What we learned, in a nutshell, was never, ever, ever, ever allow oil to get into a complex coastal system of mangroves, sea grasses, and coral reefs because you'll never get it out," said Dr. Jackson.

In this video interview with the Smithsonian Ocean Portal, he reflects on the Panama study and its implications for the Gulf oil spill, and reminds listeners that the greatest threats to the ocean- overfishing, climate change, and other types of pollution -combined actually exceed the devastation that unfolded in the Gulf of Mexico oil spill. "If there's any silver lining in the [Gulf] oil spill," he said, "it's that it might make us wake up to the magnitude of what we're dealing with."

Featured Scientist

At Woods Hole Oceanographic Institution in Massachusetts, Chris Reddy studies the long-term effects of oil spills, as well as natural oil seeps that occur off the coast of Santa Barbara, California. In this video, watch as he digs beneath the surface in Wild Harbor salt marsh in Cape Cod, Massachusetts to find layers of oil from a spill that occurred more than 40 years ago. This leftover oil continues to impact the wetland's ecology and wildlife. "When this spill first occurred in 1969, about a month after I was born, people thought that it would only last a week," he says. And to the naked eye, the marsh looks beautiful and pristine. But oil has persisted in the sediments and continues to adversely affect the marsh's mussels, crabs, and grasses. " Oil can last for a long time and has a lot of biological impact." In June 2010, Dr. Reddy testified before a Congressional panel (pdf) investigating the Gulf oil spill.

In the immediate aftermath of the Deepwater Horizon oil spill, concerns about public health focused on people coming into direct contact with the oil and dispersants. The Centers for Disease Control and Prevention offered safety advice to Gulf Coast residents and relief workers and the EPA conducted toxicity tests on dispersants. A recent study discovered dispersants had an unintended benefit during the initial oil cleanup. As the dispersant broke apart the oil into smaller droplets it also decreased the amount of harmful gases that rose to the sea surface where emergency cleanup crews were working. This decreased the health risks associated with working near the spill, reduced the number of days where it was too hazardous to work, and enabled a quicker cleanup. However, long-term questions about oil spills and their impact on human health remain. The National Institutes of Health began to address these in a study that is tracking 33,000 cleanup workers and volunteers for a decade. The research will assess whether exposure to crude oil and dispersants has an effect on physical and mental health.

As the days, weeks, and months progressed the indirect impacts related to seafood consumption also gained attention. The chemicals in oil that are of most concern to humans are called polycyclic aromatic hydrocarbons (PAHs). Some of these are known to cause cancer. The U.S. Food and Drug Administration is charged with monitoring the levels of PAHs in Gulf Coast seafood. It works in conjunction with NOAA, the EPA, and state agencies to determine which fisheries are safe to open and which ones should be closed. In order for a fishery to be reopened, it must pass both a "smell" test and a chemical analysis. Seafood cannot go to market if it contains harmful levels of PAHs or if it emits an odor associated with petroleum or dispersants. Fishing area closures peaked on June 2, 2010, when 88,522 square miles of the Gulf of Mexico were off-limits. On April 19, 2011, NOAA announced that commercial and recreational fishing could resume in all of the federal waters that were affected by the spill.

Pictures of pelicans, sea turtles, and other Gulf of Mexico wildlife struggling in oil were among some of the most disturbing images of the Deepwater Horizon oil spill disaster in 2010. According to the U.S. Fish and Wildlife Service, thousands of "visibly" oiled animals (pdf) -which include birds, sea turtles, and marine mammals-were collected by authorities in the vicinity of the Deepwater Horizon oil spill. Many of the animals were already dead, but for those found alive, dozens of organizations, including the Smithsonian's National Zoological Park and the New England Aquarium (NEA), were mobilized to rescue, rehabilitate, and later release animals affected by the spill. National Zoo personnel were dispatched to the Gulf largely to assist with the process of relocating animals affected by the spill and helping to identify future release sites for those rescued. Dr. Luis Padilla, a Zoo veterinarian who helped with a pelican release in Texas, and Dr. Judilee Marrow were among those who assisted in the Gulf.

NEA staff who helped to rehabilitate sea turtles rescued from the Gulf oil spill offered a behind-the-scenes view on the aquarium's Marine Animal Rescue Team Blog. The blog described how rescuers in boats and spotter planes were "looking for rounded mounds on the surface of the oil, which usually means that there is a turtle floating under the surface of the oil." The rescue team, based at the Audubon Aquarium of the Americas in New Orleans, treated dozens of endangered sea turtles, such as Kemp's ridley, loggerheads, green sea turtles, and hawksbills. To learn more about how oil affects marine life, watch this video from the Pew Environment Group that explains the impact of oil on marine life throughout the water column and check out this fact sheet from U.S. Fish and Wildlife which summarizes "Effects of Oil on Wildlife and Habitat." (pdf) We may not know the full effects of the spill on animals - both big and small - for years to come. (See "Ecosystem Effects.")

In testimony before a committee (pdf) of the U.S. House of Representatives, Dr. Sylvia Earle, National Geographic Explorer-in-Residence and former chief scientist of NOAA, offered specific suggestions for addressing the catastrophic oil spill in the Gulf and delivered an impassioned call for greater investment in ocean research-including more expeditions to explore the Gulf's deep waters, establishing permanent monitoring stations and protocols, and encouraging tri-national collaboration among scientists and institutions around the Gulf. "No one has descended to the greatest depth in the Gulf of Mexico, about three miles down in the Sigsbee Deep near Yucatan. In fact, no one knows for sure exactly where the deepest place in the Gulf is, or if they do, proving it has been an elusive goal," she said.

The Oil's Spread

Over the course of 87 days, the damaged Macondo wellhead, located around 5,000 feet beneath the ocean's surface, leaked an estimated 3.19 million barrels (over 130 million gallons) of oil into the Gulf of Mexico-making the spill the largest accidental ocean spill in history.

Once the oil left the well, it spread throughout the water column. Some floated to the ocean's surface to form oil slicks, which can spread more quickly by being pushed by winds. Some hovered suspended in the midwater after rising from the wellhead like a chimney and forming several layers of oil, dispersant and seawater mixtures drifting down current; during the spill a 22-mile long oil plume was reported. This plume formed because chemical dispersants, released into the water to break up the oil so it could wash away, allowed the oil to mix with seawater and stay suspended below the surface. And some oil sunk to the seafloor by gluing together falling particles in the water such as bacteria and phytoplankton to form marine snow. As much as 20 percent of the spilled oil may have ended up on top of and in the seafloor, damaging deep sea corals and potentially damaging other ecosystems that are unseen at the surface.

You can explore where the oil went in our interactive.

Clean-up Methods

When oil spills into the ocean, it is difficult to clean up. When you have 3.19 million barrels to clean up, it is even harder.

Part of the difficulty is that no two spills are alike. The amount and type of oil (whether crude or refined) affects how it spreads, and a spill in seawater spreads differently than freshwater. Local environmental conditions also play a huge role: currents, tides, weather, wind speed and direction, air temperature, water temperature and presence of ice all affect how the oil spreads and how well cleanup workers can access the spill area. This variability makes it difficult to plan for spills ahead of time.

The most basic method of clean up is to control the spread of the oil using physical barriers. When oil spills in water, it tends to float to the surface and spread out, forming a thin slick just a few millimeters thick. (A very thin slick is called a sheen, which often looks like a rainbow and can be seen in parking lots after a rainstorm.) Cleanup workers first surround the slick with floating booms to keep it from spreading to harbors, beaches or biologically important areas like marshes. Then they can use different tools to remove the collected oil. Often they will drive skimmers, boats that skim spilled water from the water's surface, through the slick.

After most of the oil is removed by skimmers, workers use sorbents to mop up the trace amounts left behind. Sorbents either absorb oil like a sponge or adsorb oil, which means that oil sticks to its surface. They come in three main types: natural organic materials like peat moss, straw, hay and sawdust; natural inorganic materials like clay, volcanic ash, sand, or vermiculite; and synthetic sorbents made of materials similar to plastic like polyurethane, polypropylene, and polyethylene. Which type is used will depend on the particular spill, as some types of sorbents work best on different types of oil and under different weather conditions.

Another option is to speed up the oil's natural biodegradation using dispersants. (See next section.)

Removing spilled oil from the environment is a difficult task. Because oil is hydrophobic (doesn't mix with water), it floats to the surface when it spills into the ocean and forms large slicks. These slicks can wreak havoc on coastal ecosystems and animals, so cleanup workers use dispersants -chemicals that break down the oil into smaller particles that mix with water more easily-to prevent them from forming. Evaporation and bacteria can then degrade these tiny droplets more quickly than if they were in a large slick, or waves can wash them away from the spill site.

Dispersants are often used when workers want to stop the slick from spreading to a protected area like a harbor or marsh. This can be a boon for animals found on the surface and coast, such as seabirds, marine mammals and those found in the Gulf's mangroves, because the oil is moved out of their habitat. But dispersants can also enter the food chain and potentially harm wildlife.

In the case of the Deepwater Horizon oil spill, clean-up workers treated the oil with over 1.4 million gallons of various chemical dispersants. Typically such large amounts are sprayed over the open ocean from an airplane or helicopter. But during the BP oil spill, they were also injected straight into the Macondo wellhead, the source of the leak, in order to reduce the amount of oil that reached the ocean surface. Five years after the spill some scientists believe that injecting dispersants directly at the wellhead may not have done much to help reduce the size of the oil droplets.

Just because the oil and dispersants are out of human sight and mind in the deep sea doesn't mean they're gone. It's possible that life in the deep sea was exposed to the dispersant-oil mixture. Scientists have found that the dispersant-oil mixture was rapidly colonized and broken down by bacteria that sunk towards the bottom. Any bits of the mixture that didn't get broken down would then get buried in coastal and deep-sea sediments, where its breakdown slows.

While the dispersant helps expose more of the oil to bacteria and waves which help to break it down, it also makes the oil more available to wildlife. One 2012 study showed that the combination of oil and the dispersant Corexit is 3 to 52-times more toxic to rotifers (microscopic animals) than oil by itself. This isn't because of anything inherently dangerous in the mixture of the two; the rotifers are more able to ingest oil once it's made accessible by the dispersant. Furthermore, the dispersants may not have been necessary. A modeling effort supported by the Gulf of Mexico Research Initiative offered evidence that the dispersants injected into the Macondo wellhead may not have helped to lessen the amount of oil reaching the surface after all.

A lot of research is still needed to fully understand the long-term effects of dispersants on the region and its inhabitants-not to mention how they move through the food chain to impact larger predators, such as people. Researchers are developing new dispersants that cause less environmental damage for the next spill. ( See "Human Health Impacts.")

Ecosystem Effects

There were some immediate impacts to the animals of the Gulf of Mexico that could be seen with the naked eye: pelicans black with oil, fish belly-up in brown sludge, smothered turtles washed up on beaches. But not much time has passed since the spill, and it will take many more years of monitoring and research to understand what happened.

Strandings of both dolphins and sea turtles increased significantly in the years following the spill. "From 2002 to 2009, the Gulf averaged 63 dolphin deaths a year. That rose to 125 in the seven months after the spill in 2010 and 335 in all of 2011, averaging more than 200 a year since April 2010," reported Reuters in 2015. Since then, dolphin deaths have declined, and long-term impacts on the population are not yet known. Kemp's ridley sea turtle nests have gone down in the years since the spill, and long-term effects are not yet known.

Seabirds were initially harmed by crude surface oil-even a small bit of oil on their feathers impeded their ability to fly, swim and find food by diving. Seabird losses may have numbered in the hundreds of thousands, but reliable estimates are hard to come by. Looking beyond the sea, researchers are currently studying how oil may have affected land birds that live in the marshes along the Gulf coast.

Invertebrates in the Gulf were hard hit by the Deepwater Horizon spill-both in coastal areas and in the deep. Shrimp fisheries were closed for much of the year following the spill, but these commercially-important species now seem to have recovered. Deep-water corals grow very slowly and can live for many centuries. Found as deep as 4,000 feet below the surface, corals near the blowout showed signs of tissue damage and were covered by an unknown brown substance, later identified as oil from the spill. Laboratory studies conducted with coral species showed that coral larva exposed to oil and dispersant had lower survival rates and difficulty settling on a hard surface to grow.

The impact of the spill on fish communities is still largely unknown. Lab studies have shown that oil can cause heart defects in the developing larvae of bluefin tuna and other fish, but we won't know if this occurred in the wild until after those larvae would have grown up. Some fish larvae populations actually grew after the spill, as they had more food in the form of oil-eating microbes.

There were some reports of deformed wildlife after the spill. For years following the spill there were reports of fish with lesions and deformities, and some reports of eyeless and deformed shrimp after the spill. However, consuming Gulf seafood is now completely safe.

Over 1,000 miles of shoreline on the Gulf of Mexico, from Texas to Florida, was impacted by oil from the Deepwater Horizon blowout. Much of this area has been cleaned, but eroded shorelines are taking longer to recover and erosion rates have accelerated in these areas.

You can explore more ecosystem effects in our interactive.

In May 2010, the Monterey Bay Aquarium Research Institute (MBARI) sent a high-tech robotic submersible to the oily waters of the Gulf of Mexico. Like other autonomous underwater vehicles (AUV), the robotic sub was programmed at the surface to navigate through the water on its own, collecting information on deep oil plumes from the Deepwater Horizon spill as it traveled. Although satellites and aircraft helped show the extent of the spill at the surface, researchers hoped that the AUV would allow them understand what was happening farther down in the water column.

During the NOAA-sponsored expedition, MBARI's AUV mapped part of a plume 1,000 meters (3,300 feet) below the surface, and collected water samples at various depths. The resulting data helped the researchers identify a persistent deep oil plume and link the oil in this plume to its source: the Deepwater Horizon blowout.

Once the over 200 million gallons of oil began spewing out of the damaged wellhead-where did it go? Keeping track of that much oil-especially as it sinks into the deep sea-is a difficult task that can't be done with eyes alone. Along with visual tracking, computer models of the oil's movement helped researchers get a better sense of what path it took and where it ended up.

To build the models, researchers first had to understand where ocean eddies, currents and waves carried the tiny oil particles. To understand surface water movement better, researchers set small, yellow boards made of wood afloat on the ocean's surface and asked beachgoers to report where they found these "drift cards" when they washed up on shore. This citizen scientist endeavor provided general information about how far the waves can carry a floating object and specific data points that can be used to improve models of where the oil disperses.

Further data collection has been ongoing since the spill by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). CARTHE has more high-tech "drift cards:" their "drifters" are small buoy-like instruments with GPS, which ping their locations to satellites as they drift on ocean currents. Their location gets tracked for weeks or months at a time and provide an unprecedented amount of location-based data for modeling. This information can be used to better predict oil movement in case of future spills.

After the Deepwater Horizon spill, oil was mixed throughout the ocean and made its way to coastal and deep-sea sediments. Researchers continue to collect samples from both the water and the sediment to determine if oil is present, and where exactly it came from. Chemical analysis of oil found after a spill can be used to determine its original source. In the case of Deepwater Horizon, tracking the origins of oil slicks that appeared after the well was capped proved helpful in determining if a new leak might have sprung.

About a month after the Deepwater Horizon oil spill (while the oil was still leaking out of the Macondo wellhead) BP announced that they would provide $500 million to fund an independent research program that would study the impacts of the spill on the environment and public health. With this funding, the Gulf of Mexico Research Initiative (GoMRI) was formed as a 10-year independent research program. The GoMRI research board, which is independent from BP, makes funding and research decisions, and as of early 2014 over $175 million has been distributed to research institutions, many of which are located in Gulf states.

At the outset, the twenty-person GoMRI board adopted five main research themes to focus on: physical movement of the oil and dispersant, degradation of the oil and its interaction with the ecosystem, environmental effects of the oil and dispersant, development of technology for improved response and remediation, and the effects of oil and dispersant on human health. GoMRI funded studies have examined where the oil went after the spill, and how the oil affected many types of marine life, including deep-sea coral ecosystems, seabirds, and jellyfish, to name just a few.

Read more about GoMRI research:

Collections

As scientists in the Gulf collect organisms potentially affected by the oil, they will need to compare them to animals from previous decades to identify how they have changed, if at all.

Here's where Smithsonian Collections can play a role. Soon after the Deepwater Horizon oil spill, Smithsonian Collections staff plotted invertebrate holdings from the Gulf onto Google Earth. Since 1979, invertebrate specimens have been deposited in the national collections of the National Museum of Natural History's Department of Invertebrate Zoology. In the Gulf of Mexico, more than 57,000 invertebrates (points on the map) from 5,789 distinct collecting sites from 14 Mineral Management Service survey programs (point colors) have been cataloged.

Following the Deepwater Horizon incident in late April 2010, collections staff updated the files to reflect the latest areas affected by the spill in real-time. "The points on the map represent less than half of our Gulf of Mexico holdings, the rest-approximately 75,000-still need to be processed and cataloged," said Bill Moser, museum specialist.

A Smithsonian study of a 1986 oil spill on the coast of Panama attracted renewed interest for its insights into the effects of oil spills on coastal systems. Working with the Smithsonian Tropical Research Institute, marine ecologist Dr. Jeremy Jackson and a team of researchers examined the spill's immediate and long-term effects on the coast in Bahia las Minas, Panama.

The benchmark study (PDF), published in 1989, documented the damage oil causes to coastal and tidal habitats. It's particularly notable because it includes 15 years of ecological data about the area before the spill collected by the Smithsonian. The affected area includes the Smithsonian biological reserve known as the Galeta Marine Laboratory. "What we learned, in a nutshell, was never, ever, ever, ever allow oil to get into a complex coastal system of mangroves, sea grasses, and coral reefs because you'll never get it out," said Dr. Jackson.

In this video interview with the Smithsonian Ocean Portal, he reflects on the Panama study and its implications for the Gulf oil spill, and reminds listeners that the greatest threats to the ocean- overfishing, climate change, and other types of pollution -combined actually exceed the devastation that unfolded in the Gulf of Mexico oil spill. "If there's any silver lining in the [Gulf] oil spill," he said, "it's that it might make us wake up to the magnitude of what we're dealing with."

Featured Scientist

At Woods Hole Oceanographic Institution in Massachusetts, Chris Reddy studies the long-term effects of oil spills, as well as natural oil seeps that occur off the coast of Santa Barbara, California. In this video, watch as he digs beneath the surface in Wild Harbor salt marsh in Cape Cod, Massachusetts to find layers of oil from a spill that occurred more than 40 years ago. This leftover oil continues to impact the wetland's ecology and wildlife. "When this spill first occurred in 1969, about a month after I was born, people thought that it would only last a week," he says. And to the naked eye, the marsh looks beautiful and pristine. But oil has persisted in the sediments and continues to adversely affect the marsh's mussels, crabs, and grasses. " Oil can last for a long time and has a lot of biological impact." In June 2010, Dr. Reddy testified before a Congressional panel (pdf) investigating the Gulf oil spill.

In the immediate aftermath of the Deepwater Horizon oil spill, concerns about public health focused on people coming into direct contact with the oil and dispersants. The Centers for Disease Control and Prevention offered safety advice to Gulf Coast residents and relief workers and the EPA conducted toxicity tests on dispersants. A recent study discovered dispersants had an unintended benefit during the initial oil cleanup. As the dispersant broke apart the oil into smaller droplets it also decreased the amount of harmful gases that rose to the sea surface where emergency cleanup crews were working. This decreased the health risks associated with working near the spill, reduced the number of days where it was too hazardous to work, and enabled a quicker cleanup. However, long-term questions about oil spills and their impact on human health remain. The National Institutes of Health began to address these in a study that is tracking 33,000 cleanup workers and volunteers for a decade. The research will assess whether exposure to crude oil and dispersants has an effect on physical and mental health.

As the days, weeks, and months progressed the indirect impacts related to seafood consumption also gained attention. The chemicals in oil that are of most concern to humans are called polycyclic aromatic hydrocarbons (PAHs). Some of these are known to cause cancer. The U.S. Food and Drug Administration is charged with monitoring the levels of PAHs in Gulf Coast seafood. It works in conjunction with NOAA, the EPA, and state agencies to determine which fisheries are safe to open and which ones should be closed. In order for a fishery to be reopened, it must pass both a "smell" test and a chemical analysis. Seafood cannot go to market if it contains harmful levels of PAHs or if it emits an odor associated with petroleum or dispersants. Fishing area closures peaked on June 2, 2010, when 88,522 square miles of the Gulf of Mexico were off-limits. On April 19, 2011, NOAA announced that commercial and recreational fishing could resume in all of the federal waters that were affected by the spill.

Pictures of pelicans, sea turtles, and other Gulf of Mexico wildlife struggling in oil were among some of the most disturbing images of the Deepwater Horizon oil spill disaster in 2010. According to the U.S. Fish and Wildlife Service, thousands of "visibly" oiled animals (pdf) -which include birds, sea turtles, and marine mammals-were collected by authorities in the vicinity of the Deepwater Horizon oil spill. Many of the animals were already dead, but for those found alive, dozens of organizations, including the Smithsonian's National Zoological Park and the New England Aquarium (NEA), were mobilized to rescue, rehabilitate, and later release animals affected by the spill. National Zoo personnel were dispatched to the Gulf largely to assist with the process of relocating animals affected by the spill and helping to identify future release sites for those rescued. Dr. Luis Padilla, a Zoo veterinarian who helped with a pelican release in Texas, and Dr. Judilee Marrow were among those who assisted in the Gulf.

NEA staff who helped to rehabilitate sea turtles rescued from the Gulf oil spill offered a behind-the-scenes view on the aquarium's Marine Animal Rescue Team Blog. The blog described how rescuers in boats and spotter planes were "looking for rounded mounds on the surface of the oil, which usually means that there is a turtle floating under the surface of the oil." The rescue team, based at the Audubon Aquarium of the Americas in New Orleans, treated dozens of endangered sea turtles, such as Kemp's ridley, loggerheads, green sea turtles, and hawksbills. To learn more about how oil affects marine life, watch this video from the Pew Environment Group that explains the impact of oil on marine life throughout the water column and check out this fact sheet from U.S. Fish and Wildlife which summarizes "Effects of Oil on Wildlife and Habitat." (pdf) We may not know the full effects of the spill on animals - both big and small - for years to come. (See "Ecosystem Effects.")

In testimony before a committee (pdf) of the U.S. House of Representatives, Dr. Sylvia Earle, National Geographic Explorer-in-Residence and former chief scientist of NOAA, offered specific suggestions for addressing the catastrophic oil spill in the Gulf and delivered an impassioned call for greater investment in ocean research-including more expeditions to explore the Gulf's deep waters, establishing permanent monitoring stations and protocols, and encouraging tri-national collaboration among scientists and institutions around the Gulf. "No one has descended to the greatest depth in the Gulf of Mexico, about three miles down in the Sigsbee Deep near Yucatan. In fact, no one knows for sure exactly where the deepest place in the Gulf is, or if they do, proving it has been an elusive goal," she said.

# data[].attributes.attachment_link.description
The Gulf oil spill is recognized as the worst oil spill in U.S. history. Within days of the April 20, 2010 explosion and sinking of the Deepwater Horizon oil rig in the Gulf of Mexico that killed 11 people, underwater cameras revealed the BP pipe was leaking oil and gas on the ocean floor about 42 miles off the coast of Louisiana.