OCEAN CURRENTS

current •mass of water moving from

one place to another•like a river within the ocean

importance:

•moves drifting organisms from place to place – plankton, disperse young

•carries eggs and larvae of organisms that have external fertilization

•brings food, oxygen•carries away waste,pollutants

three types of currents

• surface currents

• thermohaline circulation (currents)

• wind-driven vertical currents (upwelling)

surface currents•wind driven currents•occur at surface•horizontal currents•caused by friction between wind

and water - wind pushes water

surface currentsCoriolis effect•causes moving objectsin northern hemisphereto veer clockwise•causes moving objectsin southern hemisphereto move counter-clockwise

surface currentsCoriolis effect

surface currentsgyre•massive circular system of wind-driven

surface currents•cover whole oceans•clockwise inNorthern hemisphere•counter-clockwisein Southernhemisphere

surface currentseddies = warm core ringsbreak off of currents and

transport organisms elsewhere

thermohaline circulation (currents)•causes deep ocean circulation•vertical currents•temperature and salinity

cause water density differences•due to density differences,

water masses rise and fall

thermohaline circulation (currents)

↑ salinity = ↑ density = water mass sinks↑ temp. = ↓ density = water mass floats

thermohaline circulation (currents)

thermohaline circulation (currents)

•when combined with surface currents, results in conveyor belt movement of water around globe

wind driven vertical currents = upwelling•wind blows, moves water

away, causes new water to rise up to replace it