Motion in the Ocean

Ocean Currents

• Warm currents flow AWAY from the equator and towards the poles

• Cold currents flow TOWARDS the equator from the poles

It transports heat from the equator to the poles

It transports nutrients and organisms – it returns oxygen to the system and stirs up food from bottom

It influences weather and climate It influences commerce

Why is Ocean Circulation Important?

Ocean currents are rivers of circulating waters found in the ocean

There are two types: Surface Currents- the upper 400m of the

ocean (10%) Deep Water Currents- Thermal/Salinity

currents (90%)

What are Currents?

Make up 10% of the oceans’ waters

Up to a maximum depth of 400 meters

Broad, slow drifts that NEVER cross the equator

Mostly wind generated Create gyres-

enormous circular currents

Surface Ocean Currents

Migration

Importance of Surface Currents

Navigation

Weather

Makes up about 90% of the oceans’ water

Differences in density are related to salinity and temperature which causes the waters to move up or down beneath the ocean

Deep Ocean Currents

Global ocean circulation that is driven by differences in densities of the sea water which is controlled by:

Temperature Salinity (salt)

Thermohaline Circulation

Upwelling Movement of deep

water to surface Hoists cold,

nutrient-rich water to surface

Produces high productivities and abundant marine life

Importance of Deep Ocean Currents

The Wind Just as wind moves

from high pressure to low pressure, so do our waters

Winds blow across the surface creating friction and motion

The water piles up because the water currents flow slower than the winds

Factors Influencing Currents

The Sun heats the

water making it less dense and creating a convection current in the ocean

Factor also referred to as water density

Factors Influencing Currents

Water’s Salinity- Salinity means salt

content Saltwater is more

dense, so it sinks lower than fresh water

Factors Influencing Currents

The Coriolis Effect Causes water to

move right in the Northern Hemisphere (clockwise)

Causes water to move left in the Southern Hemisphere

(counter-clockwise)

Factors Influencing Currents

1. How are ocean currents produced?

2. Where do cold currents come from? Where do warm currents come from?

3. How do ocean’s impact climate?

Reflective Questions?