* Loop Current: A large piece of Gulf Stream circulation located in the eastern Gulf of Mexico. The anticyclonic or counterclockwise rotating current enters the Gulf through the Yucatan Straits, following a path that at times extends nearly to the mouth of the Mississippi River before turning south to exit through the Florida Straits. Like the larger Gulf Stream, three to four rings or eddies are shed annually from the Loop Current. * Antilles Current: A primary current of the Eastern Caribbean, the Antilles Current is spawned by the combination of flow from the North Equatorial Current and North East Trade Winds. * Continental Shelf: The seabed adjacent to landmasses that forms the submerged portion of the continent. Generally not deeper than 600 feet, the shelf normally extends out 40 miles. * Continental Slope: The steep, sloping portion of the seabed that drops off from the edge of the continental shelf. This extends down an average of 12,000 feet. * Submarine Canyon: Narrow, deeply sloping, well-defined depression in the ocean floor. Most are located along 100-fathom depths. * Eddy: Circular or spiral deviation from the main flow of the Gulf Stream, resulting in water moving in a direction opposite the main flow of the Stream. Scientists say oceanic eddies are very common and may contain as much as 99 percent of the kinetic energy of the ocean. * Gyre: The world's five gyres are large, clockwise hemispheric circulation of currents between major continental landmasses. Near the equator, tradewinds drive ocean surface waters west; near the poles, westerly winds drive the water back to the east. The combined effect creates a broad circulation of currents known as a gyre. * Sargasso Sea: Oval-shaped, warm-water mass lying between the Azores and West Indies, the Sargasso Sea is bounded on the west and north by the Gulf Stream. Water levels in the sea average 3 feet higher than adjacent waters, and outward pressure from this dome of water is balanced by the circulation of currents circling the North Atlantic gyre. * Grand Banks: This vast shoal area rises from the continental shelf of the North Atlantic lying off the coast of southeastern Newfoundland; depths range from 120 to 600 feet. The cold Labrador Current and the warmth of the Gulf Stream which border the banks create an environment ideal for the growth of the plankton on which larval and small baitfishes depend for food. The Grand Banks has been one of the world's richest fishing grounds.