Hurricane Isaac Batters Louisiana Marshes, Uncovers Oil
This story was originally published by the National Wildlife Federation.
By Craig Guillot, National Wildlife Federation
When Hurricane Isaac struck Louisiana on the seven-year anniversary of Hurricane Katrina, its winds and tidal surge caused four deaths and at least $1.5 billion in insured damages. For many residents around the Mississippi River Delta, Isaac brought back memories of two recent disasters to hit the coast — Katrina and the 2010 Gulf oil disaster. Before the storm even hit land, residents in some coastal communities noticed a rise in the number of tar balls washing ashore. Officials later discovered moderate amounts of tar balls and weathered oil in coastal Louisiana, Mississippi and Alabama.
Experts say scenes like this could be normal for decades to come and that Louisiana’s coast will require constant monitoring and a long-term plan for restoration. Despite advertising campaigns to the contrary, the region is still reeling from the Gulf oil disaster more than two years after the blow out of BP’s Macondo well.
Tar balls and oil reappears in the Mississippi River Delta
Even before Hurricane Isaac hit the coast, residents in communities from Grand Isle, La., to as far east as Gulf Shores, Ala., started to report an increase in tar balls washing ashore as the Gulf began to churn. Tar balls, sheen and various remnants of weathered oil were found following the storm in many of those areas including the pristine shorelines of Ship Island in Mississippi.
A National Wildlife Federation (NWF) team surveyed the waters and beaches near Port Fourchon, Elmer’s Island and Grand Isle on September 6 to survey the waters and beaches. While they did not find any evidence of significant oiling, they did find moderate amounts of tar balls on the beaches in Grand Isle. Tar balls have been a reality on Louisiana's coast for decades but Grand Isle residents say what was left on the beaches after Isaac was "a lot more than normal."
NWF Staff Scientist Alisha Renfro, Ph.D., said a number of tropical storms and weather events have washed up tar balls since the start of the 2010 disaster.
“They continue to wash up because there’s a lot of weathered oil still out there, either just offshore or just beneath the surface of the sand,” Renfro said.
NWF also made a trip out to Myrtle Grove, La., on September 7 to survey the damage that Isaac inflicted on the marsh. The eye of the storm first made landfall near the mouth of the Mississippi River and passed over some of the state's most fragile marshes before making a second landfall near Port Fourchon.
David Muth, Louisiana state director for NWF, said the team found evidence of localized marsh destruction. On his survey, Muth noticed hundreds of large chunks of marsh that had broken away and been deposited in open water.
“Marsh break-up occurred in areas that have a history of rapid marsh loss in Louisiana, near Myrtle Grove. Healthier marshes to the south showed no signs of break-up. The findings illustrate the importance of quickly building the authorized Myrtle Grove Sediment Diversion, which will build new marsh in this vital area.”
The NWF team also found three oiled pelicans near Myrtle Grove. A number of media outlets reported oiled birds and wildlife following the storm. While there is no connection between these findings and the Macondo disaster, Muth said, “This is further evidence that we have not yet completely learned the lessons of the Gulf oil disaster.
"Oil could be here for decades."
Even 23 years after the Exxon-Valdez spill in Prince William Sound, Alaska, oil can still be found beneath the surface. Biologists say that "sub-lethal" effects to fisheries could linger in the Gulf of Mexico for years to come.
"It will probably be an issue for a long time, especially as many people conjecture that there are still tar mats laying on the bottom that you can't easily clean up," Muth said.
In April 2012, two years after oil started pouring into the Gulf, an NWF team found heavy oil still sitting just beneath the surface on small islands in Barataria Bay and Bay Jimmy. On one island, the oil was so abundant that it oozed to the surface under each foot step. Renfro said while oil may remain below the surface during the winter, it can emerge in the spring and summer when the heat softens it up and liquefies it. Many biologists believe that reappearing oil could be an annual occurrence in the summer months.
If there’s any good news, it’s that when oil comes to the surface, sunlight and weathering can help further break it down.
“Photo-oxidation from the sunlight helps break down that material even more. It also helps reveal it so that cleanup crews can get it. Hopefully we’ll have less and less over time,” Renfro said.
Last week, Louisiana State University ran lab tests for the Louisiana Department of Wildlife and Fisheries and determined that the oil found on Grand Isle and Elmer's Island matched the footprint for the oil spilled from BP's Macondo well. BP later confirmed that the oil was from the well and that they would dispatch workers to clean it up.
Ed Overton, Ph.D., professor emeritus with the Department of Environmental Sciences at Louisiana State University, said that while oil is still out there, it is hard to tell exactly how much. Overton did say that storms can serve as “Mother Nature’s hurricane” in helping break down the oil. He believes that oil will degrade faster on the Gulf Coast than it did in Prince William Sound because of the geography of the shore.
“Our shoreline erodes and moves around more quickly. The problem with sandy beaches is that once it gets buried, you just don’t know where it is. We’ll likely see it for years but not at the level we saw in 2010,” Overton said.
Mississippi River Delta wetlands remain in a precarious state
Biologists and coastal restoration advocates say while the oil is an issue, it is only one part of a number of problems eating away at Louisiana’s wetlands. Oil has attacked the roots of plants and contributed to the death of marsh grass and mangroves but the encasement of the Mississippi River and saltwater intrusion has had a destructive impact for decades. In some areas of the marsh, the oil appears to have been the final straw.
Renfro also surveyed the Mississippi River by air on September 7 and saw heavily damaged patches of marsh between Belle Chase and Point a la Hache. She and Muth said there were clear differences in how untouched marshes fared compared to those that were heavily oiled during the summer of 2010.
“Pelican Island doesn’t look good at all. The mangrove has just been all brown and dead. It saw heavy oiling in 2010,” Muth said.
While marshes have always endured the winds and surges of hurricanes, Muth said he’s seen clear differences in how a healthy marsh can recover quickly. Further south in “healthier” areas of marsh, Muth said some parts looked almost invigorated by the storm where natural processes can deposit new layers of clay and sediment.
Renfro said the Wax Lake Delta is a clear example of how a thriving marsh can recover from a storm. After Hurricane Rita struck the area in 2005, damage to these wetlands was observed in the aftermath of the storm, but there was not a significant lasting impact. The Wax Lake Delta has been a rare success story in coastal restoration because it is fed sediment by the Atchafalaya River.
“The steady supply of mineral-rich sediments from the river help make these wetlands more resilient and allow them to recover quickly when damaged,” Renfro said.
NWF’s Greater New Orleans Program Manager Amanda Moore said it all underlines why the Gulf Coast needs a long-term comprehensive strategy for coastal restoration. NWF was instrumental in helping create and push for the passage of the RESTORE Act, a bill that ensures 80 percent of the fines and penalties from the Gulf oil disaster will be dedicated to Gulf Coast restoration.
Moore said its passage has been a monumental victory for the coast and that funding in the near future should help move along big coastal restoration projects. Ongoing monitoring of the impacts of the Gulf oil disaster will be needed to ensure a sound recovery.
“We knew that when the disaster happened, we'd be dealing with this for years to come. We need to keep vigilant and watching it because we could be dealing with this for a long time,” Moore said.