Ocean CurrentsOcean Currents

A Topic in Physical A Topic in Physical OceanographyOceanography

Ocean currentsOcean currents

• Masses of moving waterMasses of moving water

• Transport plankton, fish, heat, Transport plankton, fish, heat, momentum, and chemicals such as momentum, and chemicals such as salts, oxygen, and carbon dioxide. salts, oxygen, and carbon dioxide.

• Can be shallow or deep, slow or fast, Can be shallow or deep, slow or fast, narrow or widenarrow or wide

Ocean currentsOcean currents

• Are affected by the basin shape ( the Are affected by the basin shape ( the shape of the ocean floor)shape of the ocean floor)

• Affect marine operations( navigation, Affect marine operations( navigation, search and rescue at sea) , dispersal of search and rescue at sea) , dispersal of pollutants, & weatherpollutants, & weather

• Are either surface or deep water currents Are either surface or deep water currents

What are surface currents?What are surface currents?

• Moving water in the top layer of the Moving water in the top layer of the ocean which extends 400 feet down.ocean which extends 400 feet down.

How surface currents form…How surface currents form…

• Prevailing winds develop waves Prevailing winds develop waves and push them in one predominant and push them in one predominant direction forming surface currents direction forming surface currents

(Prevailing winds are winds that blow (Prevailing winds are winds that blow predominantly from 1 direction. predominantly from 1 direction. Describe our prevailing winds.)Describe our prevailing winds.)

The Coriolis Effect-Earth’s The Coriolis Effect-Earth’s rotationrotation

• The Coriolis Effect curls surface currents into giant The Coriolis Effect curls surface currents into giant clockwise whirlpools in the Northern Hemisphereclockwise whirlpools in the Northern Hemisphere

• Currents flow counterclockwise in the Southern Currents flow counterclockwise in the Southern Hemisphere for the same reason.Hemisphere for the same reason.

• Currents moving north or south in the northern Currents moving north or south in the northern hemisphere are deflected to the right by the hemisphere are deflected to the right by the Coriolis force.Coriolis force.

• Circling currents are called gyres and can be Circling currents are called gyres and can be thousands of miles in diameter.thousands of miles in diameter.

• Coriolis effect

Surface CurrentsSurface Currents

• can create can create eddies, swirling loops of , swirling loops of water, as they flow. These are water, as they flow. These are temporary and dissipate temporary and dissipate

• affect affect upwelling in many places in many places ( wind causing cool, nutrient dense ( wind causing cool, nutrient dense water to move upward) – important water to move upward) – important for sea life!for sea life!

Surface currents and Surface currents and ClimateClimate• Surface currents carry heat from place to Surface currents carry heat from place to

place This affects regional climates. place This affects regional climates.

• The Sun warms water at the equator more The Sun warms water at the equator more than it does at the than it does at the high latitude high latitude polar polar regions. Heat travels in surface currents regions. Heat travels in surface currents to higher latitudes. to higher latitudes.

• A current that brings warmth to a high A current that brings warmth to a high latitude region makes that region’s latitude region makes that region’s climate less chilly.climate less chilly.

Large and Famous Surface Large and Famous Surface CurrentCurrent

• The Gulf Stream, a surface current The Gulf Stream, a surface current in the North Atlantic, carries 4500 in the North Atlantic, carries 4500 times more water than the times more water than the Mississippi River. Each second, Mississippi River. Each second, ninety million cubic meters of water ninety million cubic meters of water is carried past Chesapeake Bay (US) is carried past Chesapeake Bay (US) in the Gulf Stream.in the Gulf Stream.

The Gulf StreamThe Gulf Stream

Currents whose movements are determined by coastlines

Boundary Currents

Prevailing winds and current Prevailing winds and current flowflow

http://www.classzone.com/books/http://www.classzone.com/books/earth_science/terc/content/earth_science/terc/content/visualizations/es2401/visualizations/es2401/es2401page01.cfm?es2401page01.cfm?chapter_no=visualizationchapter_no=visualization

• Write one fact that reviews what you Write one fact that reviews what you learned in this presentation.learned in this presentation.

• Write one fact that is new.Write one fact that is new.

• Write something you like to learn Write something you like to learn about the oceans. about the oceans.

Expand your knowledge…While Expand your knowledge…While viewing the videoclip ( 2:49)viewing the videoclip ( 2:49)

Ocean currentsOcean currents