Scientists surprised, cautious over environment’s apparent post-oil spill recovery

By Ben Raines, Press-Register
21 April 2011 Researchers contacted by the Press-Register expressed almost uniform surprise at the apparent rebound in nearshore environments a year after 200 million gallons of oil began pouring into the Gulf of Mexico. With the caveat that much remains unknown — and problems could still emerge at any time — scientists said their worst fears had so far not been realized. “Who would have possibly believed that you could go down to the Gulf and see it look like it looks today. People are having a hard time accepting it. Me too,” said Ed Overton, an chemist at Louisiana State University under contract to analyze oil for the federal government. “There are things that are wrong. There is still oil out there. But it is not nearly as bad as I expected it would be a year later.” Overton noted that a good deal of oil is still present in Louisiana marshes, even marshes where new growth can be seen this year. He said it will take years for that oil to work its way through the system. In the meantime, it will be important to study larval shrimp and other creatures that use those marshes as nurseries. Kevin Anson, a biologist with the Alabama Division of Marine Resources, said sampling has shown that shrimp, crabs and fish appear to be developing normally in Alabama waters. “It looks to be an average year so far,” Anson said. “There isn’t a big hole for a particular species, or a suite of species. We look at all the life stages, from juvenile to sub-adult to adult.” The most widespread ecosystem changes in the northern Gulf of Mexico resulting from the Deepwater Horizon spill were likely invisible to the human eye, said Monty Graham, a Dauphin Island Sea Lab researcher. The oil, he said, appears to have caused huge shifts in the planktonic community at the base of the Gulf food web off Alabama, where Graham conducts his research. … The swollen bacteria population may have played a role in low oxygen areas that developed off the Alabama coast during the summer. Oil-eating bacteria consume oxygen as they break down hydrocarbons, Graham said. In contrast, the planktonic creatures that were missing would have helped create oxygen. …