THE GULF STREAM, a relative newcomer on the geological scene, is an odd, fast-moving circulation of warm water that travels in an unfixed position, a few hundred miles north of Florida, up the east coast of the United States to Cape Hatteras, North Carolina, then onto Nantucket Island, before kicking eastward across the Atlantic Ocean to the British Isles. In this way, the Gulf Stream, a part of the western edge of the North Atlantic circulation, acts as a boundary that prevents the warm water of the Sargasso Sea from overflowing the colder, denser waters on the inshore side. The Gulf Stream is one of the strongest and most extensive known currents in the world, and it is separated from the United States by a narrow strip of cold water. The Gulf Stream, which can be as much as 50 mi (80 km) wide and 1,300 ft (400 mi) deep, is caused by the northeast and southeast trade winds on the surface of the water and the equatorial currents that meet in the region of the windward islands of the Caribbean Sea. The Gulf Stream’s rival, the Kuroshio Current, located along the western edge of the Pacific Ocean and the coast of Japan, is part of a transpacific system that connects the North Pacific, California, and equatorial currents. The Gulf Stream triples in volume and is strengthened by the waters from the Florida Straits, by way of the Florida Current, and by currents coming from the northern and eastern coast of Puerto Rico and the Bahamas. It can travel more than 60 mi (96 km) a day. The Gulf Stream, first mapped by Benjamin Franklin and his American whaling captain cousin Timothy Folger, early pioneers in using temperature in an attempt to define its boundaries, maintains its dimensions for nearly 1,000 mi (1,610 km) up the East Coast of the United States. Franklin, using observations of current speed in the region of the Gulf Stream and plotting them on a chart, was able to draw a river traversing the Atlantic Ocean with speeds ranging from 4 to 2 knots. The strong carry power of the Gulf Stream’s warm equatorial layers of water has a notable, almost direct effect on the climate in various parts of the Earth. As the Gulf Stream moves pass Cape Hatteras, North Carolina, it begins to flow away from the East Coast of the United States. The altered flow of the Gulf Stream, known as meanders or eddies, separates the cold slope water to the north from warm Sargasso Sea water to the south. As the Gulf Stream flows into deeper water, it carries warm water to the North Atlantic region, as it enters the Norwegian Sea between the Faroe Islands and Great Britain. Thus, the Gulf Stream, which bathes northwest Europe with warmer water and wind currents, is largely believed to be the reason for mild European climate. Too warm to encourage the kind of fish that are the main catch of North Atlantic waters, the Gulf Stream does bring well-developed specimens of tropical fish, like the Portuguese man-of-war jellyfish, much farther to north than they would normally venture. In addition, there are two particular species of plant (the double coconut tree indigenous to Jamaica) and animal life (the freshwater eels of Europe) that are carried for thousands of miles by the Gulf Stream surface transport system to the shores of Ireland and Scotland.