It's been four years since BP's Deepwater Horizon oil rig exploded in the Gulf of Mexico, killing 11 workers and sending more than 200 million gallons of crude oil gushing into the water. The public outrage has largely died down, as have the EPA restrictions on federal contracts for BP. But the devastating effects on the area's wildlife persist.
Oil is still washing up on the Louisiana shores, and severe damages to the ecosystem are still observable miles away from the Macondo well. The long-term impact of oil spills, unfortunately, reflects a sobering reality that we can expect to see for years; wildlife in the Prince William Sound has not fully recovered from the Exxon Valdez oil spill 25 years ago, and pollution from a 1969 Cape Cod oil spill was still detected as recently as 2010.
According to a new National Wildlife Federation report, over a dozen species are still struggling with disease, defects and deformities from the Deepwater Horizon disaster in 2010. Here are just some of animals hurting.
Oiled pelicans wait to be cleaned at the Bird Rehabilitation Center at Fort Jackson in Buras, Louisiana. (Getty Images)
Brown pelicans were already a threatened species when the BP oil spill occurred. After the spill, nearly one thousand were collected for cleaning, but more than 500 died. The population has largely rebounded
, with the number of brown pelicans reported nesting in 2012 nearly as high as it was pre-spill. But images of the oil-slicked pelicans became an ubiquitous part of the media's coverage, and the oil has stuck: Two years later, researchers detected chemical and petroleum pollutants from the BP spill in the eggs of white pelicans in Minnesota
, chemicals that could negatively affect embryo development.
A dolphin swims through the water off the coast of Louisiana. (Getty Images)
A late 2013 study
found dolphins in the vicinity of the BP oil spill showed previously unseen signs of sickness, including lung damage, low levels of adrenal hormones and unhealthy weight loss.
"I've never seen such a high prevalence of very sick animals -- and with unusual conditions such as the adrenal hormone abnormalities," one of the study's authors, Dr. Lori Schwacke, stated at the time.
Researchers also found an "unusual" spike in dolphin strandings; according to National Oceanic and Atmospheric Administration (NOAA) findings: In 2013, bottlenose dolphins were found dead or stranded at rates three times higher
than the average pre-spill rate.
A dead sea turtle is seen washed onto shore April 14, 2011 in Waveland, Mississippi. (Getty Images)
NOAA research released in August 2013 found large numbers of sea turtle strandings
in the years since the spill, with about 500 stranded sea turtles in the area affected every year from 2011 to 2013. (Historically, estimates for strandings in the area would have been closer to 100 per year.)
A bloated and burned juvenile sperm whale that had been found dead on June 15, 2010 in the Gulf Of Mexico. (Courtesy of Greenpeace)
It's difficult to measure just how many sperm whales were affected, but one arresting photo of a rotting, burnt sperm whale carcass
circulated widely after researchers saw the animal from a ship about 77 miles from the Deepwater Horizon site in June 2010. A 2013 study
of sperm whale skin samples found higher than usual levels of genotoxic metals in Gulf of Mexico whales after the spill, with the whales closest to the site of the spill with the highest levels.
The genotoxic metals, including nickel and chromium, are capable of damaging DNA, causing lasting genetic impacts on generations of whales. In the short term, even a few whale deaths can affect an entire population as sperm whales, already an endangered species, give birth to very few calves.
"As soon as we get to the level of three deaths caused by human interaction -- and this would include the oil spill -- that would jeopardize that particular sperm whale population," Celine Godard-Codding, an environmental toxicologist at Texas Tech University, told National Geographic
A common loon, photographed on May 6, 2012 at Port St. Joe, Florida. (Flickr)
As water birds, loons are vulnerable to water pollution -- and researchers have found they were indeed affected by the spill. A 2013 study of loons turned up dangerous levels of PAH (polycyclic aromatic hydrocarbons)
in their bloodstreams, which could contribute to anemia, weight loss, liver damage, cancer, immunosuppression and other health issues.
A bucket full of red snapper catch sits in Water Street Seafood in Apalachicola, Florida. (Getty Images)
In the immediate aftermath, red snapper in the affected area were found with lesions and rotting fins. While such physical scarring are less common in fish four years later, a recently published study
conducted between 2011 and 2013 found the population of young snappers in the Gulf unusually small, with a noticeable decline in other reef fish as well.
A mountain of oyster sheels lies outside the BP oil spill cleanup operations center on May 4, 2010 in Hopedale, Louisiana. (Getty Images)
A crab skirts tarballs of oil on a beach at sunrise on May 23, 2010 on Grand Isle, Louisiana. (Getty Images)
Crab populations are also down, with a major drop of blue crabs identified in 2013
. One reason could be still-slick marshes, which the crabs could be avoiding as they select their habitats. The remaining crabs were still showing signs of damage as of 2013.
"People are bringing in (crabs) that are really messed up," Darryl Felder, a University of Louisiana biology professor, told the Tampa Bay Times
. "The crab catches are really down, and what they're getting have big lesions on them -- lesions and fungal or bacterial infections."
A whale shark photographed on August 11, 2011, in Isla Mujeres, Quintana Roo, Mexico. (Getty Images)
Bluefin tuna, 2006. (Getty Images)
All photos were taken in 2010 in the aftermath of the spill unless otherwise noted.