The warm water spills north and south through a series of ocean currents
that mirror to some degree the cells in the atmosphere above the water.
Like the atmospheric cells, for instance, these giant oceanic gears
---called gyres--- fall unders the influence of the winds and the Coriolis
effect and form loops that move water first away from the equator, then
parallel, and then back to rejoin the equatorial currents. The familiar
Gulf Stream is one of these gyres, and because of its unique characteristics
it has particular salience to the fortunes of many civilizations.