Much of the oil spilled into the Gulf of Mexico after the Deepwater Horizon explosion in 2010 disappeared within weeks of the capping of BP’s Macondo well on July 15, digested by a massive explosion in oil-eating microorganisms, said Terry Hazen, a professor of environmental biology at the University of Tennessee-Knoxville, during a Monday panel at the national conference of the American Chemical Society in New Orleans.

Hazen was one of a team of researchers tracking the movement of oil in the Gulf from July 27 to August 26, 2010, from aboard four research ships.

Much of the oil and methane gas released by the well was originally found to be moving in a plume 3,600 feet below the surface to the southwest of the Macondo well site.

An initial scientific paper in August 2010 concluded that the tiny droplets of oil and oily material in the plume already were rapidly disappearing within a few days after the well was capped.

Further research found that there was a 10-fold increase in several types of bacteria that munch on oil molecules, Hazen said. Over time, the make-up of the different types of bacteria changed to those that were eating different toxic chemical compounds left behind when the oil was eaten by the first organisms, he said.

While the rapid disappearance of oil was a largely positive sign, Hazen said it’s still unclear whether the explosion in growth of a few oil-eating bacteria types might have itself disrupted the deepwater Gulf ecosystem. Meanwhile, oil that came to the surface also rapidly exhausted available nutrients, competing with naturally-occurring algae in the warm Gulf waters, he said.

Scientists also are unsure whether the oil and its cleanup directly affected the ecosystem before it was biodegraded and dispersed, he said.

Also unanswered, Hazen said, is how resilient the Gulf is to future combinations of hurricanes, oil spills, floodwaters from the Midwest, and the industrial and human wastes entering the Gulf from the Mississippi and other rivers.

Similar potential good news was delivered by Gabriel Kasozi, a chemistry researcher at Makerere University Kampala in Uganda, who has been part of a team of researchers from the University of Florida studying the BP oil that washed into wetlands in Barataria Bay.

Kasozi said that a study of an oiled patch of wetlands at St. Mary’s Point in the northern part of the bay found that key chemical constituents largely disappeared after a year of weathering. The findings could provide some hope for state officials concerned about stubborn areas of oiled wetlands scattered across 200 miles of Louisiana’s coastline.

However, Kasozi pointed out that the test area was several yards inland from the shoreline, and it was unclear whether oiled wetland grasses closer to the water line had disappeared, as they have elsewhere.

As with similar research results released in peer-reviewed scientific magazines or at other scientific meetings, the results of the two researchers represent only small slices of the wide body of research being conducted into the effects of the oil spill.

Much of that research is being done to support the ongoing lawsuits by the federal government against BP and other parties believed responsible for the spill, and many of the results of that research are still being withheld from the public until the legal battle is over.

In addition to the lawsuits being heard in U.S. District Court in New Orleans, the results of those studies will be used as part of the Natural Resource Damage Assessment process required under the federal Oil Pollution Act. Under that process, BP, federal agencies and the states will determine what damage was caused by the spill and come up with projects aimed at mitigating the damage or compensating the public for lost resources.