HOUMA — Oil and chemicals remaining in wetlands and on beaches still pose great risks to birds that breed or nest along hard-hit areas of the Louisiana coast, according to new National Audubon Society field surveys.
Audubon scientists headed to the coast in late September to observe and catalogue the spill’s effect on birds six months after the April 20 explosion aboard the Deepwater Horizon rig, which triggered the nation’s worst-ever oil spill. They found local birds stayed loyal to their regular coastal habitats, even those that had been affected by oil. The observed birds appeared resilient, despite scientists having taken in 1,545 live oiled birds and 1,488 dead oiled birds in Louisiana as of Thursday.
But Audubon scientists warned that the future of birds and the Gulf ecosystem remains uncertain as spill workers continue cleaning oil from beaches and marshes and searching for hidden oil in waters and under sand.
“People shouldn’t be fooled into thinking that the danger to birds and the environment is over just because the oil stopped flowing,” said David Yarnold, Audubon president and CEO. “It’s going to take years of monitoring just to understand and start dealing with the long-term impacts of the oil — and they’re just part of a much bigger threat.”
Audubon science teams conducted surveys in 23 areas, including some in Terrebonne and Lafourche, along the Louisiana coast. The teams found surface oil, tar and tar balls at many beaches and marshes and oil seepage coming from pockets inches below the sand on most beaches that were hard-hit by oil during the spill. Scientists found “tar mats” just below the waterline that they say are sending a seemingly endless stream of new tar balls ashore.
Frank Csulak, a scientific support coordinator based in Houma with the National Oceanic and Atmospheric Administration, said currently scientists are on the ground in Louisiana documenting the extent and degree of oiling.
They’re also looking for buried oil in coastal areas. It’s an exhaustive effort to determine the best cleaning method for each portion of oiled shoreline in Louisiana, he said.
“Out in Mississippi and Florida where you’re just dealing with sand beaches, cleanup is fairly standard. Here in Louisiana, it’s a much different situation because it’s a vegetated shoreline,” Csulak said.
He gave an example of a recent excursion to Bay Jimmy, in Plaquemines Parish, where officials took six plots of marsh and tested different methods of cleanup on each square.
On one plot they raked dead oiled grasses and debris off the plot to expose areas still contaminated by “sticky” oil, a term scientists use to designate unweathered oil that contains toxic components. The procedure let tides and air better degrade the remaining oil. In another area, they raked material and also flushed the marsh out with a low-pressure hose. In other plots, they raked material and treated the oil with two different kinds of detergent to break down hardened oil. They also raked and removed oiled debris and used a portable vacuum to suck up oil. On the final plot they did nothing. They plan to revisit the sites to test which method worked best for cleaning the marsh.
All of remaining oil-related threats were in close proximity to areas with large bird populations, Audubon scientists said.
“Birds aren’t wired to avoid threats from oil, and even if they look healthy now, we can’t begin to predict all the health and reproductive effects that could show up later,” said Melanie Driscoll, Audubon’s Louisiana Bird Conservation director and survey team member. “The fact that they’re still plentiful doesn’t mean they’re safe.”
The Audubon teams counted nearly 10,000 birds in surveys of 10 areas that had been heavily oiled and 13 other areas that received little or no oil contamination. The birds represented a broad array of species, including old and young brown pelicans, terns, plovers, herons, ducks and egrets, among others. The oil spill began just as pelicans were starting their 2010 breeding season on local barrier islands. As those islands were oiled, scientists worried a failed reproductive cycle would deal a major blow to the birds who’d only recently been removed from the Endangered Species List.
But Audubon chief scientist and survey leader Thomas Bancroft said sightings of young brown pelicans in flight provides reassuring evidence that juvenile birds successfully left the nest despite the contaminated and chaotic habitats on most barrier islands. But when it comes to the long-term survival of oil-affected birds, scientists still aren’t sure.
“The science suggests there’s cause for concern, but we simply can’t know what direct contact with the oil will mean for long-term health and reproductive success of pelicans or terns or any other species,” Bancroft said. “We can’t begin to fathom what the long-term effects on the marine food chain will be. This remains a giant, uncontrolled science experiment, with birds and all the communities that depend on the gulf as the unwitting subjects.”
