- Photo by Cheryl Gerber
- A photo taken last week shows globs of petroleum floating on the surface of the Gulf within 25 miles of shore.
The Chandeleur Islands, the southernmost point of Breton Sound, are a "pupping" ground where female lemon sharks give birth. The islands, devastaded by Hurricane Katrina in 2005, are the northernmost pupping site on earth for the species.
Dr. Martin O'Connell, director of the University of New Orleans Nekton Research Lab, has studied the population and tagged several sharks for research, but now O'Connell and his two graduate students are worried because oil surrounded the islands earlier this month. "We were hoping to recapture some of those tagged fishes this summer, look at their growth, see how they're using the islands — but now it could be a moot point," he says.
At frequent press conferences, representatives from BP, the Coast Guard, the state and federal government have repeated the phrase "worst-case scenario," preceded by "we've been prepared," when discussing the potential environmental apocalypse wrought by oil gushing unchecked from the heart of the Gulf of Mexico. That scenario changes daily as 210,000 gallons of oil spew from the ocean floor at the site of the Deepwater Horizon rig, which exploded April 20. The cause of the accident is still under investigation. For the wetlands, barrier islands, marine life and other organisms, as well as the Gulf itself, the worst-case scenario is a dire one.
While the slick creeps toward the coast, about 284 miles of booms have been laid to protect fragile areas, according to information given May 12 to a congressional panel probing the spill. What are they protecting? These wetlands and barrier islands surrounding coastal Louisiana, including the Chandeleurs, are vital to the interior; they help reduce the impact of hurricanes and other storms, protect interior marshes, provide habitats for wildlife and nurseries for aquatic life. Thousands of species, including lemon sharks, are now at risk.
"If we had those marshes out there as a barrier, more complete barrier islands, more complete marsh fronts — we would have a lot less damage with this size oil slick," O'Connell explains.
Angelina Freeman, a scientist with the Environmental Defense Fund (EDF), has observed the coast with the National Oceanic and Atmospheric Administration (NOAA). "The ecosystem itself is stressed. ... Oil and gas canals could potentially be a pathway for oil to push further into wetlands," she says. "The degradation of barrier islands (makes) interior wetlands more susceptible. Interior canals and oil and gas canals fragment into marsh and increase saltwater intrusion, (which) could also be a conduit for some of the oil."
O'Connell's students have studied fish along the coast, observing the renewed populations recovering from Katrina. But because there are fewer habitats, the fish group around whatever's left. "Katrina kind of put the ecosystem on edge for a while," he says. "Now these animals are concentrated where the oil is going to be coming, from the Gulf side to the bay side. It's just going to cause more damage. We were looking at a worst-case scenario with the erosion and sea level rise, and just kind of holding on, hoping we wouldn't get another Katrina, and then we have this popped on top."
The porous barrier protecting Louisiana's coast could be compromised. A black layer could form under estuaries, preventing crabs from burrowing into their habitat, and plants from establishing roots. Even stubborn, resilient species like redfish, speckled trout and blue crab, which should thrive in these systems, could face a decline. Endangered wildlife also depends on them, including Kemp's Ridley sea turtles, which are on their way to Mexico and Texas beaches, and brown pelicans, which recently were removed from endangered species lists. Now their future remains unclear.
"You can drop a nuclear device in the lake, and next year pretty much all the species are going to be back," O'Connell says. "It's this long-term decline — people don't realize fisheries are getting worse and worse. This oil spill is pretty much putting the cap there. We are pretty low down when it comes to recovering from Katrina and the marsh loss. This is just going to put us back 10, 20 years, at the minimum."
The first images of the Gulf oil disaster's wildlife victims — oil-drenched birds that dove into the slick and dead jellyfish covering Gulf beaches — began to show the spill's lethal scope before the oil even touched land.
There is the immediate harm from contamination, but the EDF also warns of sub-lethal effects — impacts on reproduction cycles and the next generations of fish and wildlife, a bottom-up effect with the potential to wreak havoc on everything from the smallest organisms in the Gulf to the largest, all of which rely on the food cycle crippled by oil.
"Oil can be toxic to algae, plankton — everything that forms the basis of the food chain," says EDF biologist Stacy Small. "There's not only an effect on fish, shellfish and fisheries but also larger life-forms all the way up to top predators. These things take time to see. We may see oiled birds right away, but the problem is, it's not going to go away."
The bottom line is oil will have an impact, whether it's pushed forward on land or absorbed into sediment on the sea floor. When oil meets land and water, a few things can happen. Chemicals affect estuary-dependent species, which ride the tide to get into marshes and ride it back out. Any chemical that's a "little bit off, even if it's a smell," O'Connell says, could skew the movement of those organisms. Then there are the effects on interface feeders, like water-skipping mullet, which feed from the bottom to the surface; a slick on the top of the water would prevent that. Animals also can be affected by direct toxicity if a tide brings in a large amount of oil, trapping wildlife in back marshes and killing fish in its path.
Then, as Small explains, there are the potential long-term effects. Even if migratory animals and larger fish are able to find cleaner waters to roam, when they return they face the toxicity of their former habitat. Toxins absorbed by the smallest of organisms could remain in the food web, and only time can mitigate the damage.
Doug Rader, the EDF's chief oceans scientist, says there are other equally important yet overlooked habitats and marine life that could take a beating from the spill — in the area of the spill itself, in deep sea habitats and on beaches.
In the early stages of life, fishes thrive in the top layers of the sea, a vital area for feeding and transportation. The Gulf Loop Current to the south of the spill is a "superhighway" for that migration, Rader says. "We did some modeling to see how long it took for larvae to get from where they spawn to where they end up, and it showed it only takes 10, 12 or 14 days to travel very long distances," he says. "If the oil gets into the Gulf Loop Current, it can get to south Florida in less than two weeks."
In the northern Gulf's deep sea, there is the Viosca Knoll, a deepwater coral reef thousands of years old and home to a wide variety of marine life. "Marine snow," a phenomenon of floating particles mixed with marine life skeletons, mucus and other particles, provides an important nutritional source to deep sea organisms. Rader is concerned oil and the chemical dispersants used to break up the petroleum could rain into the abyss, disrupting habitats far below the surface.
On beaches, there is the recognized and immediate impact on people — tourism, fishing industries and livelihoods. Rader says the surf zone also is an important foraging ground for small fishes and sharks, and the sand is a lunch counter for migrating shore birds and the things they eat. The surrounding wetlands also provide habitats for migratory birds and nurseries for offshore species in early stages of life.
Fortunately and unfortunately, the Gulf offers a dynamic wind and water current system — things can change rapidly. Concentrated oil can be broken up, depending on the timing and speed with which the source is capped. While some scientists prepare for a worst-case scenario to combat the oil and heal its victims, others remain optimistic.
Unlike the heavy crude oil spilled by the Exxon Valdez in 1989 in Prince Williams Sound, the oil flowing into the Gulf is 5,000 feet down and is a "lighter" sweet Louisiana crude, which presents a unique situation for the Lake Pontchartrain Basin Foundation (LPBF).
About a mile offshore from the Chandeleurs, an LPBF team (and O'Connell) encountered a long ribbon of "orange globular stuff" on the water surface and in the water column. "We think, 'OK , emulsified oil, it's got to be,'" the LPBF's Anne Rheam says. "We get samples, send them off to the lab — it's not oil. It's biologic material. Two days after we were there, oil did wash up. These waves of streams, some of it is not actually oil. Where real oil is, is the question.
"What we're seeing — we are concerned because this thing keeps gushing — is that over time, with southeast winds, we are concerned about it potentially getting into the lake," Rheams says. "As of now, it's not. ... Our job is to say, 'We know this basin, we know this watershed, this is what you need to protect.' That's one way we're able to prepare."
As conservationists brace for potential impact to the lake, O'Connell hopes people will continue the LPBF's mission to heal Lake Pontchartrain, its watershed and its culture.
Rader remains cautious in overstating risks and threats — there are livelihoods at stake, beyond animal life. "People have a tendency to shy away from seafood they worry about being contaminated," he says. "But the truth is, the vast majority coming from Louisiana is not only wholesome but safe. It's at risk from perception as much as reality."