Boundary current a basin (such as the Gulf Stream, a current on the western side of the Atlantic Ocean) are stronger than those on the eastern boundary (such as the California Current, on the eastern side of the Pacific Ocean). Western intensification was first explained by the American oceanographer Henry Stommel. In 1948, Henry Stommel published a paper in "Transactions, American Geophysical Union" titled "The Westward Intensification of Wind-Driven Ocean Currents", in which he used a simple, homogeneous, rectangular ocean model to examine the streamlines and surface height contours for an ocean at a non-rotating frame, an ocean characterized by a constant
Atlantic Ocean is interrupted by larger transform faults at two places: the Romanche Trench near the Equator and the Gibbs Fracture Zone at 53°N. The MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other. The MAR rises above the surrounding ocean floor and its rift valley is the divergent boundary between the North American and Eurasian plates in the North Atlantic and the South American and African plates in the South Atlantic. The MAR produces basaltic volcanoes in Eyjafjallajökull, Iceland, and pillow lava on the ocean floor.