Tag Archives: BP Deepwater Horizon Oil Spill Commission

Crude Oil in the Bile of Fish: BP Horizon Oil Spill

Since the 2010 BP oil spill, marine scientists at the University of South Florida (USF) have sampled more than 2,500 individual fish representing 91 species from 359 locations across the Gulf of Mexico and found evidence of oil exposure in all of them, including some of the most popular types of seafood. The highest levels were detected in yellowfin tuna, golden tilefish and red drum. The study represents the first comprehensive, Gulf-wide survey of oil pollution launched in response to the Deepwater Horizon spill.

Over the last decade have examined the levels of polycyclic aromatic hydrocarbons (PAHs), the most toxic chemical component of crude oil, in the bile of the fish. Bile is produced by the liver to aid in digestion, but it also acts as storage for waste products.

“We were quite surprised that among the most contaminated species was the fast-swimming yellowfin tuna as they are not found at the bottom of the ocean where most oil pollution in the Gulf occurs,” said lead author Erin Pulster…Pulster says it makes sense that tilefish have higher concentrations of PAH because they live their entire adult lives in and around burrows they excavate on the seafloor and PAHs are routinely found in Gulf sediment. However, their exposure has been increasing over time, as well as in other species, including groupers, some of Florida’s most economically important fish. …

Oil pollution hot spots were also found off major population centers, such as Tampa Bay, suggesting that runoff from urbanized coasts may play a role in the higher concentrations of PAHs. Other sources include chornic low-level releases from oil and gas platforms, fuel from boats and airplanes and even natural oil seeps — fractures on the seafloor that can ooze the equivalent of millions of barrels of oil per year.

Excerpts from Firste Gulf of Mexico-wide survey of oil pollution completed 10 years after Deepwater Horizon, Science Daily, Apr. 15, 2020

The Impact of Oil Spills on the Deep Sea: the Deepwater Horizon Oil Spill

The Louisiana University Marine Consortium (LUMCON) published in September 2019 a study on the Deepwater Horizon Oil Spill in Royal Society Open Science.  The BP’s Deepwater Horizon oil rig exploded in April 2010, killing 11 workers.  The subsequent cleanup and restoration had cost nearly $65 billion..but while while we can burn off and disperse oil on the surface, but we don’t have the technology to get rid of oil on the seafloor. So approximately 10 million gallons of it settled there….In 2017 , the The LUMCON surveyed the site surrounding the wreck of the rig, and another one 1,640 feet north. There were no giant isopods, glass sponges, or whip corals that would have jumped (metaphorically) at the chance to colonize the hard substrate of the rig, such as discarded sections of pipe…..But]  crabs were just about everywhere. The researchers were shocked by the sheer number of crustaceans and other arthropods that had colonized the spill site. According to rough estimates, Atlantic deep sea red crabs, red shrimp, and white caridean shrimp were nearly eight times more populous at the Deepwater site than at other spots in the Gulf. “Everywhere there were crabs just kicking up black plumes of mud, laden with oil,” Nunnally says. But abundance does not mean the site was recovering, or even friendly to life. Particularly eerie was the crab’s achingly slow movement. “Normally, they scatter when they see the ROV lights,” he says. But these crabs seemed unbothered, or unaware of the robot’s presence.

Crabs on the seabed of the Deepwater Horizon oil spill

The researchers hypothesize that degrading hydrocarbons are what’s luring unwitting crabs from the surrounding seafloor to the deep-sea equivalent of a toxic dump. “The chemical makeup of oil is similar to the oils naturally present on crustaceans,” Nunnally says. “They’re attracted to the oil site, but everything goes downhill for them once they’re in the area.” A similar kind of chemical confusion occurred at an oil spill in Buzzards Bay in New England in 2003, which attracted hordes of American lobsters. The researchers liken the death trap to the La Brea Tar Pits: Once lured in, the crabs lose their ability to leave. With no other species able to thrive in the area, the crabs have no food source—except each other. And as one might imagine, consuming the flesh of a toxin-riddled crab or starving to death in a deep-sea tar pit is sort of a lose/lose situation.

The crabs also looked anything but normal: some claws shrunken, some swollen, shriveled legs, a dusting of parasites. “There were deformities, but mostly things were missing,” Nunnally says. “You come in with eight legs and try to get away on four or five.” The researchers have yet to ascertain what specific toxins led to these maladies. The shrimp looked just as awful as the crabs. “They didn’t look like shrimp from other sites,” Nunnally says, adding that many of the small crustaceans had humps in their backs—tumors, perhaps.

Excerpts from SABRINA IMBLERS, A Decade Later, the Deepwater Horizon Oil Spill Has Left an Abyssal Wasteland, Atlas Obscura, Sept. 18, 2019