Ocean waters are constantly on the move. How they move
influences climate and living conditions for plants and animals,
even on land. Currents flow in complex patterns affected by
wind, the water's salinity and heat content, bottom topography,
and the earth's rotation. Dynamic Ocean Topography (952 kbyte
mpeg) Animation of two years of satellite-derived Dynamic Ocean
Topography data from the Topex/Poseidon Mission Upwelling brings
cold, nutrient-rich water from the depths up to the surface.
Earth's rotation and strong seasonal winds push surface water
away from some western coasts, so water rises on the western
edges of continents to replace it. Marine life thrives in these
nutrient-rich waters §. Deep water forms when sea water entering
polar regions cools or freezes, becoming saltier and denser.
Colder or saltier water tends to sink §. A global "conveyor
belt" set in motion when deep water forms in the North Atlantic,
sinks, moves south, and circulates around Antarctica, and then
moves northward to the Indi