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