reporter: well, the scientists who have discovered this are still debating what this means and how big this is. it s not a big, thick blob of oil. it s very thin. it s a mixture of oil droplets and water not diminishing it in any way but properly trying to describe it. their biggest concern is that it s there, they have noticed some oxygen depletion around the edges of the oil and their concern is it could lead to more oxygen depletion which could affect our marine life deep under the ocean. you re talking 2,000 to 4,000 feet below this surface and so this is just another indication of how widespread this oil is. they ve described it almost like a salad dressing consistency. it s not the really thick blob but it s down there and scientists are quite worried about it. it s not killing marine yet life that they know of but it could because of the oxygen depletion, alex. okay. mark potter, thank you for that sobering update. officials in florida are investigating the cause of a