Five years after the Deepwater Horizon disaster that claimed 11 oil workers and left the Gulf of Mexico slick with crude, what remains are questions.

Why are the harvests from public oyster grounds so meager? Why have more than a thousand dolphins been stranded in the northern Gulf since the Deepwater Horizon blew up (95 percent of them dead)? Is there a connection to the oil spill? Why has the number of Kemp's Ridley sea turtle nests nosedived in the last two years? Does it have to do with the fact that the turtles swam and ate in the same waters polluted with oil, in what was the biggest spill in U.S. history?