PENSACOLA: At a laboratory in central Florida, biologist Aaron Gavin uses tiny pipettes to carefully feed shrimp to more than 700 corals living in huge saltwater tanks with sunlight-mimicking lamps glowing above them. The work of the scientists here could be the last chance to save the species that make up the only coral reef in the United States' continental waters. Gavin and his team have diligently recreated the coral reef habitat found in the waters off the southern tip of the state complete with artificial currents and local fish.