Barbados is, in many ways, an anomaly. It lies east of the main Lesser Antilles chain in the Atlantic Ocean. Fringing reefs are largely absent, although there is a small fringing structure near Folkestone on the leeward west coast. There are also sub-surface reefs along this coast, where a gently sloping shelf extends about 300 meters seaward to a depth of 10 meters. At the edge of the shelf, the sea floor drops evenly to a depth of about 20 meters. Seaward from this there are further submerged patch reef structures, together with two larger bank barrier reefs, 12-20 meters deep and up to 100 meters wide. Offshore, submerged bank barriers are also found off the southeast coast. The eastern, Atlantic, coast is subject to very high wave energies throughout the year, and much of this coastline is a bare carbonate platform extending out to deep water. Nearshore reefs in Barbados have suffered considerably. Reef flat corals disappeared over 100 years ago with the intensification of agriculture, while considerable declines in coral cover and diversity have been reported on offshore reefs since the 1980s, linked to eutrophication from urbanization and tourism developments.