Saint Croix, largest island of the U.S. Virgin Islands, in the eastern Caribbean Sea.
It lies some 65 miles (105 km) southeast of Puerto Rico and 40 miles (65 km) south of St. Thomas. In the west some hills run parallel to the coast, culminating in Mount Eagle (1,088 feet [332 metres]) and Blue Mountain (1,096 feet [334 metres]). It is the only island of the group with an extensive plain, most of which is cultivated. A meagre growth of secondary scrub has replaced former seasonal forests, which were sacrificed for sugarcane plantations. The town of Christiansted, on the northern coast, is the capital, but Frederiksted, on the western coast, is commercially more significant.
Visited by Christopher Columbus, who named it Santa Cruz, St. Croix (both names mean Holy Cross) was colonized by both the English and the Dutch in 1643, though the latter were driven out after quarrels. As sugar production became more profitable, St. Croix increased in attraction, and in 1650 the English themselves were expelled by the Spanish, who in turn succumbed to French conquest. In 1651 the Knights of Malta acquired St. Croix but resold it to the French West India Company in 1665. It became a French colony in 1674 but during 1696–1733 was uninhabited. In 1733 the king of Denmark bought it; subsequently it shared the general history of the Virgin Islands.
Caribbean Sea, suboceanic basin of the western Atlantic Ocean, lying between latitudes 9° and 22° N and longitudes 89° and 60° W. It is approximately 1,063,000 square miles (2,753,000 square km) in extent. To the south it is bounded by the coasts of Venezuela, Colombia, and Panama; to the west by Costa Rica, Nicaragua, Honduras, Guatemala, Belize, and the Yucatán Peninsula of Mexico; to the north by the Greater Antilles islands of Cuba, Hispaniola, Jamaica, and Puerto Rico; and to the east by the north-south chain of the Lesser Antilles, consisting of the island arc that extends from the Virgin Islands in the northeast to Trinidad, off the Venezuelan coast, in the southeast. Within the boundaries of the Caribbean itself, Jamaica, to the south of Cuba, is the largest of a number of islands.
Together with the Gulf of Mexico, the Caribbean Sea has been erroneously termed the American Mediterranean, owing to the fact that, like the Mediterranean Sea, it is located between two continental landmasses. In neither hydrology nor climate, however, does the Caribbean resemble the Mediterranean. The preferred oceanographic term for the Caribbean is the Antillean-Caribbean Sea, which, together with the Gulf of Mexico, forms the Central American Sea. The Caribbean’s greatest known depth is Cayman Trench (Bartlett Deep) between Cuba and Jamaica, approximately 25,216 feet (7,686 metres) below sea level.
The geologic age of the Caribbean is not known with certainty. As part of the Central American Sea, it is presumed to have been connected with the Mediterranean during Paleozoic times (i.e., about 541 to 252 million years ago) and then gradually to have separated from it as the Atlantic Ocean was formed. The ancient sediments overlying the seafloor of the Caribbean, as well as of the Gulf of Mexico, are about a half mile (about one kilometre) in thickness, with the upper strata representing sediments from the Mesozoic and Cenozoic eras (from about 252 million years ago to the present) and the lower strata presumably representing sediments of the Paleozoic and Mesozoic eras (from about 541 to 66 million years ago). Three phases of sedimentation have been identified. During the first and second phases the basin was free of deformation. The Central American Sea apparently became separated from the Atlantic before the end of the first phase. Near the end of the second phase, gentle warping and faulting occurred, forming the Aves and Beata ridges. Forces producing the Panamanian isthmus and the Antillean arc were vertical, resulting in no ultimate horizontal movement. The sediment beds tend to arch in the middle of the basins and to dip as landmasses are approached. The younger Cenozoic beds (formed during the last 65 million years) are generally horizontal, having been laid down after the deformations occurred. Connections were established with the Pacific Ocean during the Cretaceous Period (from about 145 to 66 million years ago) but were broken when the land bridges that permitted mammals to cross between North and South America were formed in the Miocene and Pliocene epochs (about 23 to 2.6 million years ago).
The existing sediment cover of the seabed consists of red clay in the deep basins and trenches, globigerina ooze (a calcareous marine deposit) on the rises, and pteropod ooze on the ridges and continental slopes. Clay minerals appear to have been washed down by the Amazon and Orinoco rivers, as well as by the Magdalena River in Colombia. Coral reefs fringe most of the islands.
The Caribbean Sea is divided into five submarine basins, each roughly elliptical in shape, which are separated from one another by submerged ridges and rises. These are the Yucatán, Cayman, Colombian, Venezuelan, and Grenada basins. The northernmost of these, the Yucatán Basin, is separated from the Gulf of Mexico by the Yucatán Channel, which runs between Cuba and the Yucatán Peninsula and has a sill depth (i.e., the depth of the submarine ridge between basins) of about 5,250 feet (1,600 metres). The Cayman Basin, to the south, is partially separated from the Yucatán Basin by Cayman Ridge, an incomplete fingerlike ridge that extends from the southern part of Cuba toward Guatemala, rising above the surface at one point to form the Cayman Islands. The Nicaraguan Rise, a wide triangular ridge with a sill depth of about 4,000 feet (1,200 metres), extends from Honduras and Nicaragua to Hispaniola, bearing the island of Jamaica and separating the Cayman Basin from the Colombian Basin. The Colombian Basin is partly separated from the Venezuelan Basin by the Beata Ridge. The basins are connected by the submerged Aruba Gap at depths greater than 13,000 feet (4,000 metres). The Aves Ridge, incomplete at its southern extremity, separates the Venezuelan Basin from the small Grenada Basin, which is bounded to the east by the Antillean arc of islands.
Subsurface water enters the Caribbean Sea across two sills. These sills are located below the Anegada Passage, which runs between the Virgin Islands and the Lesser Antilles, and the Windward Passage, which stretches between Cuba and Hispaniola. The sill depth of Anegada Passage is between 6,400 and 7,700 feet (1,950 and 2,350 metres), whereas that of the Windward Passage is between 5,250 and 5,350 feet (1,600 and 1,630 metres).
North Atlantic deep water enters the Caribbean beneath the Windward Passage and is characterized by its rich oxygen content and by a salinity of slightly less than 35 parts per thousand. From there it divides to fill the Yucatán, Cayman, and Colombian basins at depths near 6,500 feet (2,000 metres). This Caribbean bottom water also enters the Venezuelan Basin, thus introducing high-oxygen water at depths of 5,900 to 9,800 feet (1,800 to 3,000 metres). Subantarctic intermediate water (i.e., water differing in several characteristics from the surface and bottom layers of water that it separates) enters the Caribbean below the Anegada Passage at depths of 1,600 to 3,300 feet (500 to 1,000 metres). Above this water, the subtropical undercurrent and surface water enter. The shallow sill depths of the Antillean arc block the entry of Antarctic bottom water, so that the bottom temperature of the Caribbean Sea is close to 39 °F (4 °C), as compared with the Atlantic bottom temperature of less than 36 °F (2 °C).
Surface currents, bearing both high- and low-salinity water depending on the source, enter the Caribbean mainly through the channels and passages of the southern Antilles. These waters are then forced by the trade winds through the narrow Yucatán Channel into the Gulf of Mexico. The wind-driven surface water accumulates in the Yucatán Basin and the Gulf of Mexico, where it results in a higher average sea level than in the Atlantic, forming a hydrostatic head that is believed to constitute the main driving force of the Gulf Stream. Of the water passing through the Yucatán Channel each second, only about one-fourth represents the deeper Subantarctic intermediate water. The remainder is the surface water that passed over the Antillean arc at depths of less than 2,600 feet (800 metres).
While the vegetation of the Caribbean region is generally tropical, variations in topography, soils, rainfall, humidity, and soil nutrients have made it diverse. The porous limestone terraces of the islands are generally nutrient-poor. Near the seashore, black and red mangroves form dense forests around lagoons and estuaries, and coconut palms typify the sandy vegetation of the littoral. Both the Central American region and the Antillean islands are on the routes of birds migrating to or from North America, so that large seasonal variations occur in the bird populations. Parrots, bananaquits, and toucans are typical resident Caribbean birds, while frigate birds, boobies, and tropic birds can be seen over the open ocean.
The shallow-water marine fauna and flora of the Caribbean centres around the submerged fringing coral reefs, which support diverse assemblages of fishes and other forms of marine life. The marine biota is derived from the Indian and western Pacific oceans via the Panamanic Seaway, which was closed by the rise of the Isthmus of Panama some four million years ago. Coral reef growth throughout the Antillean region is favoured by uniformly warm temperatures, clear water, and little change in salinity. Submerged fields of turtle grass are found in the lagoons on the leeward sides of reefs. Sea turtles of several species, the manatee, and the manta (devil) ray (Manta birostris) are also characteristic of the region. The spiny lobster is harvested throughout the Caribbean and is sold mainly to restaurants and tourist hotels, while the queen conch and reef fishes are local staples.
Virgin Islands Network of Environmental Educators
Seeing a need to improve environmental and cultural education opportunities throughout the U.S. Virgin Islands, the V.I. Network of Environmental Educators (VINE) was formed in August 2004 by educators wanting to share information and community contacts. Co-founded by Captain Dee, VINE members work together to offer environmental education programs and provide resources for teachers and the community.
VINE is actively developing new programs and materials for use on a number of issues, including the impacts of water pollution, the role of mangroves in the marine environment, the life cycle of the leatherback sea turtle, energy conservation, the cultural history of the virgin islands and preventing soil erosion to name a few. Read More>>