Atlantic Ocean as the mid-19th century. During the Age of Discovery, the Atlantic was also known to English cartographers as the Great Western Ocean. The International Hydrographic Organization (IHO) defined the limits of the oceans and seas in 1953, but some of these definitions have been revised since then and some are not used by various authorities, institutions, and countries, see for example the CIA World Factbook. Correspondingly, the extent and number of oceans and seas varies. The Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea,
Milky seas effect than the traditional blue or white milky seas effect seen by the rest of the world. It is not known whether this difference depends on the area, or simply a perception of a cyanic colour as being green. The phenomenon is known as "mareel" in Shetland. This term is derived from the Norn word "*mareld", which is itself derived from the Old Norse word "mǫrueldr", which is a compound of "marr" (mere, sea) and "eldr" (fire). Milky seas effect Milky seas, also called mareel, is a luminous phenomenon in the ocean in which large areas of seawater (up to )