Transcript Ocean Currents - Livonia Public Schools

Ocean Currents
A Topic in Physical Oceanography
Ocean currents
• Masses of moving water
• Transport plankton, fish, heat,
momentum, and chemicals such as salts,
oxygen, and carbon dioxide.
• Can be shallow or deep, slow or fast,
narrow or wide
Ocean currents
• Are affected by the basin shape ( the
shape of the ocean floor)
• Affect marine operations( navigation,
search and rescue at sea) , dispersal of
pollutants, & weather
• Are either surface or deep water currents
What are surface currents?
• Moving water in the top layer of the ocean
which extends 400 feet down.
How surface currents form…
• Prevailing winds develop waves and
push them in one predominant
direction forming surface currents
(Prevailing winds are winds that blow predominantly
from 1 direction. Describe our prevailing winds.)
The Coriolis Effect-Earth’s rotation
• The Coriolis Effect curls surface currents into
•
•
•
giant clockwise whirlpools in the Northern
Hemisphere
Currents flow counterclockwise in the Southern
Hemisphere for the same reason.
Currents moving north or south in the northern
hemisphere are deflected to the right by the
Coriolis force.
Circling currents are called gyres and can be
thousands of miles in diameter.
Surface Currents
• can create eddies, swirling loops of water,
as they flow. These are temporary and
dissipate
• affect upwelling in many places ( wind
causing cool, nutrient dense water to
move upward) – important for sea life!
Surface currents and Climate
• Surface currents carry heat from place to
place This affects regional climates.
• The Sun warms water at the equator more
than it does at the high latitude polar
regions. Heat travels in surface currents to
higher latitudes.
• A current that brings warmth to a high
latitude region makes that region’s climate
less chilly.
Large and Famous Surface
Current
• The Gulf Stream, a surface current in the
North Atlantic, carries 4500 times more
water than the Mississippi River. Each
second, ninety million cubic meters of
water is carried past Chesapeake Bay (US)
in the Gulf Stream.
The Gulf Stream
Boundary Currents
Currents
whose
movements
are
determined
by coastlines
Prevailing winds and current flow
http://www.classzone.com/books/earth_scie
nce/terc/content/visualizations/es2401/es2
401page01.cfm?chapter_no=visualization
Expand your knowledge…While
viewing the videoclip ( 2:49)
• Write one fact that reviews what you
learned in this presentation.
• Write one fact that is new.
• Write something you like to learn about
the oceans.
Ocean currents