Transcript Surface Currents and Deep Currents Currents  Current: A horizontal movement of water in a welldefined pattern.  In the ocean, there are.

Surface Currents and
Deep Currents
Currents
 Current: A horizontal movement of water in a welldefined pattern.
 In the ocean, there are surface currents and deep
currents.
Surface Currents
 What do you think causes surface currents?
 Answer: WIND.
 What do you think affects the direction surface currents
flow?
 Answer: Controlled by 3 factors: Air currents (such as
major wind belts), Earth’s rotation (Coriolis Effect), and
the location of the continents (deflect and divide
currents).
World Surface Currents
North Atlantic Gyre
North Pacific Gyre
Heat transfer by surface currents
 What do you notice about
how surface currents
transfer heat?
 Answer: Warm water is
brought from equator
towards poles. Cold water
from poles to the equator.
 What causes England to be
fairly warm even though it is
the same latitude as Canada?
 Answer: Warm water from
Gulf Stream.
Deep Currents
 Unlike surface currents, deep currents are not caused or
controlled by winds.
 Deep Currents: A stream-like movement of ocean water
deep below the surface.
 Any ideas on how deep currents form?
 Answer: Density differences due to changing salinity
and temperature (Thermohaline Circulation).
Ocean Conveyer Belt of Deep
Currents
Deep Currents
How does the conveyer belt
work?
 At poles, water freezes. As
freshwater is locked up in
ice, saltier water is left in
the ocean.
 Saltier water is more dense
and it sinks.
 As surface water is pulled
in to replace sinking water,
a deep current is formed.
 This process drives the
global conveyer belt.
Climate Change
 How could a warming global climate affect earth’s
conveyer belt?
 Answer: Warming could cause increased rainfall in the
North Atlantic, and the melting of glaciers and sea ice.
This fresh water could disrupt the sinking of cold, salty
water. This sequence of events could slow or even stop
the conveyor belt, which could result in potentially
drastic temperature changes in Europe and elsewhere.