To celebrate the purchase of its 11-acre field station at Blackbird Caye on Belize's Turneffe Atoll, the San Francisco-based Oceanic Society is leading a special Jan. 11-18 expedition to Turneffe with marine scientist Sylvia Earle. Divers and snorkelers will explore coral reefs and, with luck, encounter dolphins and manatees in the atoll's interior lagoons. They also will observe some of the island's endangered wildlife. Evening presentations by Earle and other experts round out each day. Depending on the accommodations selected, snorkelers pay $2,095-$2,250, while scuba divers are charged $2,295-$2,450, including lodging, meals, excursions, programs, airport transfers and local taxes. Round-trip airfare to Belize City is additional. Although the field station is open for individual stays year-round, this special week is based at a nearby resort, with accommodations in air-conditioned cabanas. (800-326-7491;