Oceanography

The Ocean and Its CurrentsEQ: How do the physical properties of

the ocean, as well as atmospheric conditions influence ocean currents?

Distribution of Water

• Oceans 97%

• Ice Caps & Glaciers 2%

• Atmosphere 0.001%

• Rivers & Lakes 0.009%

• Inland Seas 0.008%

• Groundwater 0.625%

Where is water found on Earth?

I. The Ocean is Salty

• Salinity: amount of dissolved solids in the ocean

• Measured in parts/thousand (ppt)

• Range: 33-38 ppt or 3.3% to 3.8%

Where Did the Salt Come From?

• Rivers

• Volcanoes

• Dust/Rain

II. What Affects Salinity?

Anything that changes the amount of water…

• Icebergs melting: lowers salinity

• Icebergs forming: raises salinity

• Rain runoff: lowers salinity

• Sea ice melting: lowers salinity

• Sea ice forming: raises salinity

• Evaporation: raises salinity

Ocean Surface Temperature

• The ocean’s surface temperature is mostly a factor of solar energy absorbed…

• What is the graph telling you?

High prec. = low salinity High evap. = high salinity

III. Ocean Density

• Density is mass divided by volume…what does this mean?

• How heavy something is for its size, for example a dry sponge is a lot less dense than a wet sponge

• Density is a big deal because sea water that is more dense will sink in the ocean and vice versa

Imagination!

IV. What Changes Density?• 2 main things

– Add salt (increase salinity) and you make the water more dense

– Add temperature (heat) and density drops

• Temperature has the biggest affect…

• Floating in the Dead Sea!

https://www.youtube.com/watch?v=aTcyACmiaho&disable_polymer=true

Ocean CurrentsMass movement or flow of ocean water

“River within the ocean”

2 Types:

Surface currents or circulation

Deep ocean currents or circulation

a) Gyres: Huge whirls of ocean water

1. 5 main ones in the world: North Pacific, South Pacific, North Atlantic, South Atlantic, and Indian Ocean

V. Surface Circulation

What causes surface currents?

Global Winds

Global Winds

B. Coriolis effect: the effect of earth’s rotation on the currents moving them away from their original path

https://www.youtube.com/watch?v=mPsLanVS1Q8

V. Surface Circulation

VI. Effects of CirculationA. The currents have a large effect on climate

Warm water currents

- On the east coasts of continents

- Brings warm water to colder regions

VI. Effects of CirculationA. The currents have a large effect on climate

Cold water currents

- On the west coasts of continents

- Brings cold water to warmer regions

B. Upwelling: the movement of deep, colder, nutrient rich water upward to replace the hot water at the surface.

C. Nutrients promote growth of fish and plants

VI. Effects of Circulation

A. In the deep-ocean the currents do not move horizontally but vertically called density currents

i. Density currents: vertical currents that result from the density difference among the water masses

ii. Caused by changes in temperature or salinity

VII. Deep-Ocean Circulation

Thermohaline Circulation

VII. Deep-Ocean CirculationB. This happens most at high latitudes

i. The water is cold, consistently at all depths

ii. Ice forms at the top which increase density of the water, sinking it to the bottom.

C. These combine to create a conveyor belt