It's been one year since the BP oil spill devastated the U.S. Gulf Coast, sending 4.9 million barrels of oil gushing out into the waters of the Gulf.   But scientists say it could take years, even decades, before we know the full environmental impact of the spill.

Just in the past few months, hundreds of sea turtles and dolphins has washed up dead on the shores of the Gulf Coast.  It's not clear just how many of those deaths are directly connected to the spill.  But scientists say it's an unusual – and troubling – development.  Rob Marciano takes us out with a Mississippi group that answers the call of animals in distress.