Introduction to Ocean Currents
Currents are cohesive streams of seawater that circulate through the ocean. Some currents are short-live and small and other are vast and they take a long time to complete a circuit of the globe. The Gulf Stream currents follows the course through the North Atlantic for millennia. A small currents called Eddy spins off the Gulf Stream dies out within few months. Currents are caused by wind , gravity, and density.
A surface circulation stirs up a thin upper layer of the sea and for deep circulation sweeps along the deeper sea floor. Surface circulation makes patterns called Gyre-a. It's a roughly circular flow and five big gyre spins in subtropical water. Two of them are I the Atlantic and Pacific oceans. The other one is in the Indian Ocean. Small polar gyres stirs the northern Atlantic and Pacific and one surface currents circles endlessly around Antarctica. Wind is the most important cause of surface currents. When the wind is strong, sustained winds blows across the sea a drags a thin layers of water into motion.also energy from the wind is fast dissipated so wind driven currents slows down with depth and dies out within a few hundreds of meter.
Intense sunlight heats and expands into the seawater, raising the surface by several centimeters in the tropics. Coriolis effect pulls of gravity when the currents goes down the slopes. The currents moves at an angle instead of following parallel to the wind or straight down the steepest surface. Coriolis effect changes the airplanes flights because the earth's surface rotates faster at the equator. It influence mostly paths of moving objects that are loosely of the ground.
The currents veer goes to the east because when objects moves higher, slow moving latitudes the object rotate of the surface. The Gulf Stream moves away from the equator and flows to the north. Since the gulf stream is strong, deep, and fast it can transport an enormous amount of heat toward the poles.
Longshore currents flows along the coastlines when waves run into the shores at an angle. What the longshore current do is they bulldoze great volume of sand along the shore that causes beaches to disappear and harbor to fill in. Rip currents are obstacles channel water away from the shor
Upwelling currents are when winds pushes the surface water away from the shore and deeper water rises to fill a gap. They are very important to productivity because cold currents bring nutrients to the surface and stimulate high plant and animal. The Global Conveyor Belt is mostly in North Atlantic, Africa, South America and Antarctica.
The currents are important to us humans because it help us catch fishes by landlocked the creatures. Also because they partially regulate the global climate and govern the productivity of fishing grounds. Upwelling currents support blooms of algae and seaweed so humans can catch fishes. For example Herring, anchovy, and sardines are mostly in the upwelling zone and easy to harvest them.
The ocean currents moderate the planets temperature. For example western boundary currents carries heat from the tropics toward the poles. Eastern boundary currents brings cooler temperature to low latitudes. Global warming could alter currents patterns for a least a short time.