Four Years Later, Gulf's Marine Life Still Feeling Significant Impacts From Deepwater Horizon Oil Spill
April 18, 2014

Four Years Later, Marine Life Still Feeling Significant Impacts From Deepwater Horizon Oil Spill

Lawrence LeBlond for - Your Universe Online

As the fourth anniversary of the Deepwater Horizon accident in the Gulf of Mexico approaches, much of the region’s environment and marine life are still feeling the effects of the largest accidental oil spill in US history.

Despite the continued impact on the environment and wildlife, BP – formerly British Petroleum – said in a statement on Tuesday that it has ended its “active cleanup” of Louisiana’s coast. This follows last year’s end of active cleanup in Florida, Alabama and Mississippi.

BP’s announcement also follows a directive issued by the US Coast Guard transitioning the active cleanup phase to a new response phase in which crews and equipment will be pre-positioned for future response to cleanup if new reports of oil surface.

"Our response posture has evolved to target re-oiling events on coastline segments that were previously cleaned," said Coast Guard Capt. Thomas Sparks, who serves as federal on-scene coordinator for the BP response to the spill. "But let me be absolutely clear: This response is not over - not by a long shot. The transition to the Middle Response process does not end clean-up operations, and we continue to hold the responsible party accountable for Deepwater Horizon cleanup costs.

"We are absolutely committed to continuing the clean-up of Deepwater Horizon oil along the Gulf - for as long as it takes, and to surge as necessary and as the situation dictates," Sparks said, as cited by Manuel Torres of The Times-Picayune.


The Deepwater Horizon oil spill and oil rig explosion, which claimed the lives of 11 workers on April 20, 2010, subsequently released more than 200 million gallons of oil into the Gulf waters for 87 days before the well-head could be capped off.

Since the accident, BP has invested more than 70 million personnel hours and has spent more than $14 billion on “response and cleanup activities.”

“Immediately following the Deepwater Horizon accident, BP committed to cleaning the shoreline and supporting the Gulf’s economic and environmental recovery. Completing active cleanup is further indication that we are keeping that commitment,” John Mingé, chairman and president of BP America said in a company statement, according to Torres.

The Coast Guard, which was tasked with overseeing the cleanup efforts, will be in charge of monitoring the coast of Louisiana for the foreseeable future, and will decide if and when BP will need to return to clean up newly contaminated areas.

BP said it has cleaned up more than 14,000 miles of shoreline and has conducted more than 4,400 miles of ground surveys. It said it had found oil in 1,104 miles of coast, with 778 miles requiring some level of cleanup. Also, the company said it excavated more than 40,000 holes and pits in seven barrier islands in Louisiana and found oil below ground level, with less than three percent of those holes and pits warranting cleanup.


While BP ends its active cleanup activities, environmentalists and conservation experts are likely to continue pointing fingers due to the ecological impact the oil spill has had on the Gulf of Mexico and its wildlife.

A paper published in the journal PLOS ONE last September said that the ecosystem could take decades to recover from the 2010 accident. In particular, researchers looked at how the oil spill impacted the sea floor and its inhabitants.

The researchers said that when offshore drilling sites are investigated, pollution is often found within 300 to 600 yards of the drill site. However, during the study team’s expedition to the Macondo wellhead under the Deepwater Horizon platform in 2013, they discovered pollution more than two miles from the wellhead, with a severe reduction of biological abundance and biodiversity occurring in a region about nine miles around the wellhead. As well, moderate impacts were found as far as 57 miles around the site.

“The tremendous biodiversity of meiofauna in the deep-sea area of the Gulf of Mexico we studied has been reduced dramatically,” Dr. Jeff Baguley, an expert on meiofauna (small invertebrates that live in both marine and fresh water) from the University of Nevada, Reno, said in a statement at the time.

An earlier report, which was released around the second anniversary of the oil spill, found evidence of deformed seafood in the Gulf, raising an alarm on the disaster’s effect on marine life in the region.

Dr. James Cowan, a researcher with Louisiana State University’s Dept. of Oceanography and Coastal Sciences, found signs of mutated shrimp, fish with sores, underdeveloped blue crabs and eyeless crabs and shrimp, which was a likely result of the impact left by the oil spill.

Now, four years after the oil spill, experts are still concerned about the ecological impact the Deepwater Horizon oil spill has had on the Gulf Coast region.

In fact, a new report released by the National Wildlife Federation details how the effects of the oil spill has impacted at least 14 species of marine animals in the region – animals that depend on a healthy Gulf. The report was drawn up using data from a group of independent scientists and the National Oceanic and Atmospheric Administration (NOAA).


The highlights of the report details the impact the Gulf disaster has had on bottlenose dolphins. Since April of 2010, more than 900 of these marine mammals have been found dead or stranded in the region. In 2013, dolphins were found dead at more than three times the normal rates.

Studies on these animals have found that those in one heavily-oiled area of the Louisiana coast have unusual lung damage and immune system problems. A group of federal scientists say there is strong evidence that the oil from the Deepwater Horizon accident is the key cause of these dolphins’ sicknesses. Scientists are investigating further how oil may be implicated in the continuing wave of dolphin deaths being seen across the northern Gulf of Mexico.

Dolphins may be dying in record numbers in the Gulf of Mexico, but they are not the only creatures feeling the effects of contamination.


The NWF report also highlights the plight of five species of sea turtles that occur in the Gulf region. All five species are listed as endangered under the Endangered Species Act and have been threatened over the years from habitat degradation, accidental capture by fisheries and fishing equipment, egg poaching and strikes by passing vessels.

In 1987, regulations were enforced to help bring turtles back to substantial numbers. Among the regulations included devices used by shrimpers that allow turtles to escape shrimp nets – these devices have benefited sea turtles greatly in the Gulf of Mexico.

However, a survey of the Gulf shortly after the Deepwater Horizon oil spill showed that tens of thousands of these endangered sea turtles were exposed to surface oiling. As well, more than 1,000 sea turtles were stranded in the northern Gulf between April 26, 2010 and December 2011 (reports indicated that not all of these turtles were visibly oiled).

Still, sea turtle deaths remain far above normal in the Gulf region. Between 2011 and 2013, more than 1,500 sea turtle carcasses were found in Alabama, Louisiana, Mississippi and the upper Texas Coast. While it is difficult to prove that this number is significantly higher than the historical average, a NOAA report estimates that before the 2010 oil spill, fewer than 100 sea turtle carcasses wound up on Gulf beaches annually.

Because sea turtles live for decades, the full extent of impacts to these marine reptiles may not be known for a long time. The oil spill has the potential to stall decades of progress in recovering sea turtle populations.

According to the NWF report, nearly 75 percent of the stranded sea turtles found in 2013 were Kemp’s ridleys, a species that was once on the brink of extinction. This species only nests in the Gulf of Mexico and its favored foraging habitats overlap the region that was affected by the oil spill.


Around 700 sperm whales live year-round in the Gulf of Mexico. Even decades after commercial whaling was outlawed, these animals have remained endangered.

An ongoing investigation by the NOAA is examining the impacts that whales and dolphins face in light of the 2010 Deepwater Horizon disaster. The agency’s investigation includes five sperm whales that have habitat overlapping the area affected by the oil spill.

One researcher from the University of Maine has found higher levels of DNA-damaging metals such as chromium and nickel in sperm whales from the Gulf region compared to those elsewhere in the world. These metals are also present in the oil from the spill. The research showed that whales closest to the blowout site at the Macondo wellhead showed the highest levels of metal contamination.

The oil spill caused sperm whales to move south away from the well and there is some evidence that the marine mammals are still spending less time in a 1,500-square-mile area of the blowout where they usually feed -- researchers believe this is likely due to the effects of the oil spill.

While the significance of this behavior is currently not known, experts are concerned that these whales are being forced out of their natural habitat into less suitable regions. Scientists may never fully understand the extent of whale mortalities following the spill, as less than four percent of sperm whale carcasses are typically recovered, according to the NWF report.


The population of the brown pelican was originally reduced during the early 20th century when the practice of hunting caught wind on these large marine birds. Furthermore, widespread agricultural use of DDT in the 1950s and 1960s also caused significant reproductive failure of these birds.

After a ban on DDT in 1972, experts began relocating pelicans from the Atlantic coast to Louisiana to help in the bird’s recovery. The successful efforts led to the bird being removed from the federal endangered species list in 2009.

But now, the brown pelican is threatened once again due to the Deepwater Horizon oil spill. As of May 2011, some 826 brown pelicans were exposed to oil and collected from the spill area. Of these, 577 have died. More than 40 percent of all pelicans collected were visibly oiled. As well, experts found significant oiling in mangrove thickets used by the birds for nesting.

Still, there is reason to believe that these birds have not been dramatically affected by the oil spill as they continue to have sizeable populations in the region. A US Fish and Wildlife Service report in May 2011 showed that the brown pelican population in the Gulf region is around 85,000, meaning less than one percent of birds may have been affected by the oil spill.

A federal investigation looked into the potential impacts on the brown pelican as part of the oil spill litigation, but information on that study has not yet been made public.

Scientists do know that brown pelicans can ingest oil while preening their feathers, by eating contaminated food or by ingesting contaminated sediment. Internal oil exposure can lead to long-term physiological, metabolic, developmental and/or behavioral effects, which can cause a big impact on survival and reproduction.

Wildlife officials believe the numbers released by the 2011 FWS report are likely low by a factor of at least 10. Also, they warn that the worst is not over for the brown pelicans and other bird species living in the northern Gulf of Mexico.

Accurate counts of wildlife deaths in oil spills are always difficult because stricken animals frequently crawl away or sink to the bottom of bodies of water, while others become easy targets for predators, according to Melanie Driscoll of the National Audubon Society and director of bird conservation for the Gulf Coast.

She said that to compensate for those factors, spill specialists use multipliers supplied by computer models, noting that most spill counts are based on carcasses that were found and not an accurate picture of how many were killed.

Driscoll said after the Exxon Valdez oil spill that occurred off the coast of Alaska in 1989, scientists put the number of dead birds at 225,000 – the figure was based on the application of multipliers ranging from 10 to 30 to the total number of carcasses recovered.

“In some cases the multiplier can be 12 or 5 or even 20,” said Driscoll. “I’ve seen a number as high as 50 by one group for dolphins and whales in this spill. So that would mean if 20 dead dolphins were collected, you multiply that number by 50, and you get 1,000 – which would be much closer to the actual damage done.”

“In this spill I would expect the multipliers for birds to be huge,” she told The Lens’ Bob Marshall.

She arrives at this estimation because of the fact that recovery operations during the Deepwater Horizon oil spill faced additional setbacks and complications. The spill occurred at the beginning of the five-month nesting season for pelicans and other birds, and it covered a much larger area – 68,000 square miles – than the Exxon Valdez disaster – 11,000 square miles.

“The decision was made not try to recover dead birds from the nesting islands to avoid causing even more deaths,” said Driscoll. “That meant most of those sites were not searched until late August or early September at the earliest” — months after the disaster struck, in April.


Bottlenose dolphins, sea turtles, sperm whales and brown pelicans may be at the top of list of concerns for most experts, but the NWF report also highlights the impacts felt on a number of other marine creatures that make the northern Gulf of Mexico their home.

Among these include the Atlantic Bluefin tuna, the blue crab, the common loon, coral, the eastern oyster, foraminifera, gulf killifish, red snapper, the seaside sparrow and the white pelican.

The Atlantic Bluefin tuna is one of the largest fish in the Gulf, reaching lengths of 6.5 feet and weighing more than 550 pounds. These fish were just beginning their breeding season when the oil spill occurred in April of 2010. By 2011, NOAA researchers estimated that as many as 20 percent of larval fish may have been exposed to the oil, with a potential reduction in future populations of about four percent.

As the species was already in trouble, the impacts of the oil spill will only confound the future well-being of these fish. Recovery efforts will be difficult as Atlantic Bluefin tunas have seen reductions in reproductive success due to the oil spill.

A recent study has already shown that a chemical in oil from the spill can cause irregular heartbeats in both Bluefin and Yellowfin tuna that can lead to heart attacks or even death.

The Deepwater Horizon disaster also had differing impacts on the deep sea corals around the northern Gulf of Mexico. Shortly after the oil spill, a survey of coral colonies more than 12 miles from the wellhead showed no apparent impacts from the spill. However, those seven miles away were heavily impacted.

Marine life associated with deep sea corals also showed visible signs of impact from the oil.

In a lab study published in the journal PLOS ONE in 2013, coral larvae that had been exposed to oil and a chemical dispersant all had lower survival rates than control larvae in clean seawater.

However, the full extent of the damage caused from the oil spill and the chemical dispersant used to clean up the region is uncertain. It is likely to be hundreds of years before the full impact on coral is known as these deep sea animals grow very slowly over centuries.

Perhaps one of the biggest impacts on the Gulf waters happens on a scale that may not be seen, but is felt by many marine species.

Foraminifera, which comprises of more than a thousand known species in the Gulf of Mexico, is an important marine creature that forms part of the base of the marine food web, serving as a source of food for many marine animals, including snails, sand dollars and fish.

Previous research has shown that these sediment-dwelling microorganisms are sensitive to oil damage. The rapid accumulation of oiled sediment on the sea floor between 2010 and early 2011 contributed to a dramatic die-off of foraminifera in the northern Gulf waters. Nine months after the spill, researchers had still not seen a recovery of diversity of deep sea foraminifera.


As a result of the damaging effects of the Deepwater Horizon oil spill, numerous animals, plants and habitats will likely have a long and slow recovery. Scientists will likely be measuring the impacts for years and possibly decades to come.

It will be essential for scientists, conservation experts and governments to continue monitoring the environment and the animals therein. As well, it is important that mitigation on the damages and restoration of degraded and weakened ecosystems begin as soon as possible to help restore the northern Gulf, according to the NWF report.

As well, commerce will continue to be affected by the damaging effects of the Deepwater Horizon disaster for years to come, with fisheries and commercial fishermen among those feeling the biggest impact.

As for BP, a continued presence in the Gulf under the watchful eye of the US Coast Guard will be important in ensuring that any oil that surfaces in the future is taken care of quickly and properly to protect and preserve wildlife that are trying to recover from the worst accidental oil disaster in US history.