The Bermuda carbonate platform is a particularly interesting area to investigate the distribution of benthic foraminifera in recent sediments. Bermuda lagoons, marine caves, mangrove swamps, landlocked marine ponds, and reefs form a wide variety of subtropical carbonate environments where foraminiferal biofacies can be established (Javaux 1999). The Bermuda Islands also include the most northern reefs and mangrove swamps in the Atlantic Ocean, and are located within deep waters, far from the continent (1,000 km east of Cape Hatteras). A comparison with previous studies of foraminiferal distributions in subtropical/tropical, continental-margin or insular environments such as the Gulf of Mexico, the Caribbean Sea, and the Florida-Bahamas platform shows general similarities with Bermuda despite some differences (Javaux 1999).

Bermuda is a chain of approximately 150 oceanic islands located at latitude 32°N and longitude 65°W in the northwest Atlantic Ocean. The islands lie on the Bermuda Seamount, a volcanic peak capped by Quaternary limestone. The islands are fossil aeolianite dunes, perched on the southeast margin of an elliptical submarine platform (shallower than 18 m) surrounded by reefs and enclosing a reef-filled lagoon. The seaward margin of the platform extends from the platform to the ocean: a rim of coral reefs and occasional algal-vermetid cup reefs (especially on the south side) enclosing the lagoon, a wide upper terrace at 18 m depth (relict aeolianite dunes), a ridge (fossil reef) at 14.4 m depth on the outer edge of the upper terrace, and a sediment-covered terrace at 73 m depth (relict aeolianite dunes). These features were strongly influenced by Quaternary glacio-eustatic and climatic oscillations (Stanley and Swift 1968).

The warm waters of the Gulf Stream contribute to the subtropical climate of the Bermuda islands. A northern equatorial current joins the Gulf Stream after passing on the east side of the Bahamas. The Bermuda carbonate platform includes a wide range of environments such as mangrove swamps, lagoons, landlocked marine ponds, marine caves, and reefs. The islands have no rivers. Reefs are built by corals and algae, and are encrusted by numerous organisms including the foraminifera Homotrema rubrum (Lamarck). The Bermuda platform includes numerous types of reefs differing by their size, shape, and main framework-building organisms (corals or algae) (Logan 1988). The reef organisms are less diverse than their Florida and Caribbean counterparts. Fringing mangrove swamps are almost exclusively concentrated along the north shore of the islands, as well as in protected bays and around landlocked marine ponds. Mangrove swamps develop in very sheltered areas in bays, sounds, narrows and channels. Swamp floras are similar to those in the Gulf of Mexico at 23°N, and are composed of the black mangrove (Avicennia germinans), the red mangrove (Rhizopora mangle), and the buttonwood (Canocarpus erectus), with the Brazil pepper tree (Schinus portulacastrum) invading the swamps.

The recent sediments are nearly 100% calcium carbonate, and are derived almost entirely from skeletal material of benthic invertebrates (zooantharian? corals, gorgonians, sponges, bivalves, gastropods, foraminifera) and calcareous algae, or from surrounding limestones (Upchurch 1970; James and Schenk 1983). Borers (bivalves, sponges such as Cliona, polychaete worms, and barnacles) produce the major portion of reef sediment. Grazers (parrot fish, sea urchins, and chitons), and physical weathering also contribute to the destruction of rock and reef. Land erosion is important only in nearshore and inshore environment (Morris et al., 1977).