With an estimated 172 million gallons of oil and 2 million gallons of dispersants put into the Gulf during the disaster, toxins will likely remain in some areas for years. Peter Hodson, PhD, professor in the Department of Environmental Studies and Biology at Queen’s University specializes in fish toxicology and said some of the most concerning compounds are polycyclic aromatic hydrocarbons (PAHs), many of which are highly carcinogenic. While they are metabolized by vertebrates like fish and birds, they can build up in the tissues of invertebrates such as crabs and zooplankton because these organisms can’t excrete them very well.

“There is a big difference when you cross that line between having a backbone and not having a backbone. Invertebrates will build [toxins] up in the tissues but fish can excrete it,” said Hodson.

The fish will eventually feed on those invertebrates and absorb some of the toxic carcinogens but because the compounds are secreted so readily, there is little risk of carcinogenic chemicals working their way high up the food chain.

Nevertheless, the most dangerous impacts are the ones that are less apparent and may not be known for years to come. Martin O’Connell, PhD, an associate professor in the Department of Earth and Environmental Sciences at the University of New Orleans, expressed greater concern over what may have already happened. Because the Gulf oil disaster struck during the height of breeding season for many species, he believes that the toxicity may have had an immediate impact on eggs and larval organisms.

His team will have to collect next year’s data to find out what happened but he’s concerned that some species could show diminished future populations. One of his research crews discovered baby tarpon in the waters near Port Sulphur, Cocodrie and in the Mississippi Sound near Ocean Springs.

“It’s not like populations have been wiped out. There are signs of reproduction but the biggest risk is that we may see dips in populations in some areas years from now. When those [larval organisms and eggs] are supposed to be adults, they just might not be there,” said O’Connell.

Hodson said some of the compounds that were spilled in the Gulf were especially toxic to embryos and while those fish embryos can metabolize and excrete some of the toxins, they can also cause deformities. If toxicity to embryonic fish has already wiped out age classes in some areas, it could ultimately cause complications in the food chain.

“The problem is that those fish influence the species they feed on and also the species that feed on them. You have a whole shift in ecosystem structure and if you knock out those embryos, the effects could be years,” said Hodson.

Doug Inkley, PhD, senior wildlife biologist with the National Wildlife Federation, pointed out that in other disasters such chemical compounds have also been shown to affect everything from appetites to mating behaviors. Those effects could be detrimental to individuals in the population that could affect a whole year class. And when smaller species in the food chain are in low abundance, they can not only impact the next species in the food chain but cause ripple effects.

“If larger organisms further up the food chain were to die from starvation, it could have a very long term impact. There is also competition going on and if you kill of 90 percent of a species, another species moves in and takes its place, those remaining 10 percent may have a very hard time recovering,” said Inkley.

Bruce Stein Ph.D., a conservation scientist with National Wildlife Federation, said that such cascading effects on the food web may be one of the spill’s most lasting impacts. And what makes it so more detrimental is that the impacts may not be fully understood for some time.

“The time lag in detecting food chain impacts will present challenges for devising strategies for recovering and restoring the Gulf’s fish and shellfish,” said Stein.

The year of the Exxon Valdez oil disaster in Alaska in 1989, the stocks of herring, a critical fish to Alaska’s ecosystem & economy, stayed fairly steady.

The next year? Still relatively stable. So a lot of people thought the threat had passed.

But four years later, herring stocks collapsed. Fishing licenses, which had been sold from one generation of fishermen to the next and served as a dependable retirement fund, were suddenly worthless. The effects rippled up the food chain as predators like orcas were deprived of a critical food source.

Today, two decades later, herring stocks still haven’t recovered. 

So if anyone tries to tell you that today, just three months into the Gulf oil disaster, we can declare it “over,” tell them about Alaska’s herring — and the people & wildlife who once depended on them.

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For all the latest news on how the oil spill is impacting the Gulf Coast’s wildlife & to learn how you can help, visit NWF.org/OilSpill.

Animation via Wikimedia Commons

The National Oceanic & Atmospheric Association (NOAA) announced today that about half of the petroleum in the Gulf oil disaster has been captured, evaporated, burned or skimmed, with another quarter being naturally or chemically dispersed beneath the Gulf’s surface. Additionally, BP is

So what does that mean for the Gulf? Here’s what Dr. Bruce Stein, National Wildlife Federation associate director for wildlife conservation & global warming, said today:

The National Wildlife Federation is encouraged by reports of progress in permanently sealing the Gulf oil gusher and at removing oil from the Gulf’s surface. But even with so much oil captured or evaporated, there remains the equivalent of multiple Exxon Valdez disasters on and below the Gulf’s surface, fouling the Gulf Coast’s coastal habitats and hurting its wildlife. Already in August, hundreds more birds and dozens more endangered sea turtles have been rescued or found dead. That’s in addition to the thousands of birds, turtles, and dolphins already impacted since the disaster began.

It’s troubling that reports are lumping dispersed oil still lurking under the water’s surface with oil that’s been captured, contributing to the sense that the oil that’s been swept under the rug is no longer a problem. Scientific evidence shows this oil is far from gone – in fact, scientists at Tulane University have found across the Gulf signs of an oil-and-dispersant mix under the shells of tiny blue crab larvae, creatures that are part the base of the Gulf’s food chain.

Our experience with previous oil disasters like the Exxon Valdez shows the full impact of an oil disaster may not be apparent for months or years to come. It wasn’t until four years after the Valdez disaster began that local herring stocks collapsed – and more than two decades later, neither that critical food source for people and wildlife nor the jobs that depended on them have recovered.

We agree with NOAA’s conclusion that we don’t know the full extent of the impacts of this oil disaster on the Gulf’s ecosystems or the communities that depend on it. It would be irresponsible to draw conclusions about the Gulf oil disaster’s full impacts with so many questions still unanswered.

Yesterday, the National Wildlife Federation released an open letter (PDF) signed by nine top scientists urging Attorney General Eric Holder and BP CEO Robert Dudley asking for full public release of all scientific data related to the Gulf Coast oil disaster. While some data has been released, other information such as species-specific data on bird oilings and deaths remains unavailable. In an effort to obtain more complete data on bird injury and deaths related to the spill, the National Wildlife Federation has also filed a Freedom of Information Act request (PDF) with the U.S. Fish & Wildlife Service.

Help ensure NWF has the funding needed to be on the front lines helping wildlife >>
 

For all the latest news on how the oil spill is impacting the Gulf Coast’s wildlife & to learn how you can help, visit NWF.org/OilSpill.