for that we turn to david valentine, professor of microbiology and geochemistry at the university of california at santa barbara. he's made six research expeditions to the gulf in the past two years. and garret graves, chairman of the coastal protection and restoration authority of louisiana. he's also the state's lead trustee for a collective effort by five gulf states and the federal government to assess the spill's environmental impact. david valentine, i'll start with you, give us an overview, first, of the state of the spill area two years later. >> well, the state of the spill area we know that there is still significant damage that occurred. much of the oil that came out, rough 5 million barrels, much of that went away. it went to the atmosphere. it was degraded by light or degraded by microorganisms. but much of it landed in places like marshes, beaches, the sea floor and the deep ocean. and so there are pockets of damage that are still there. there are areas that are still seeing the impacts, although maybe not as wide spread as had been initially feared. >> brown: garret gr