Keith Crandall : Five years after the Deepwater Horizon rig exploded , we are only beginning to notice its effects on the Gulf . A crab ##bing will be a key element of the ecosystem , he says .
Keith Crandall : Five years after the Deepwater Horizon rig exploded , we are only beginning to understand its effects on the Gulf . A crab species may be a key indicator of the impact , he says .