1. Water on Earth
All living things need water in order to carry out their body
processes and maintain their habitats
Where is water found?
Oceans % of Earths water is salt water
Rivers and Lakes- 3% of Earth’s water is fresh water
Ice- 2/3 of fresh
water is ice
Ground water-
1/3 of fresh water is
underground
You should be able to
describe the steps of
the water cycle
Evaporation
Transpiration
Condensation
Sublimation
Precipitation
Infiltration

2. Conditions in the ocean
Exploring the Ocean
Conditions in the ocean
Salinity- total amount of dissolved salts in a sample of water.
Near surface of ocean, precipitation, melting snow and ice decrease salinity
Evaporation increases salinity
Ocean water near poles has higher salinity because when water freezes, it leaves salt behind.
Salinity causes ocean water to freeze at -1.9oC instead of 0oC like fresh water
Salt water has higher density than fresh water
Temperature
Temperatures vary with location and season
As depth increases, temperature decreases.
Pressure
As depth increases pressure increases

3. Currents and Climate Surface Currents
Current- Large stream of moving water, like a river with in the ocean
Surface currents affect water to a depth of several hundred meters. They are caused mainly by wind.
Most move in a circular pattern, moving east to west then the opposite way to complete the circle
Why do currents
move in a circular
fashion?
THE CORIOLIS
EFFECT-due to the
Earth’s rotation, winds
and currents take a curved
path, right in the
Northern Hemisphere and
left in the
Southern Hemisphere.
The Gulf Stream
Largest and most powerful
surface current in North
Atlantic Ocean
30 km wide and 300 m deep
Moves warm water from the Gulf of Mexico to Caribbean sea
Curves eastward at coast of NC due to the coriolis effect
Has a warming effect on the climate nearby land areas

4. Currents and Climate
Climate- pattern of temperature and precipitation typical of an area over a long period of time.
Currents affect climate by moving cold and warm water around the globe
Warm water from tropics toward poles, cold water from poles toward tropics
Mid Atlantic (VA, NC)= moderate climate (mild winter, humid summer) due to Gulf Stream.
A surface current warms or cools the air above it affecting climate of land near the coast
Warm currents pick up moisture = brings mild rainy weather
Cold currents can hold less moisture and cool the air=brings cool dry weather

5. Currents and Climate
El Nino-An abnormal climate event that occurs every two to seven years in the Pacific Ocean, causing changes in wind, currents and weather patterns for 1-2 years
Occurs every 2-7 years in Pacific Ocean
Unusual pattern of winds in western Pacific
Last one occurred
Warm water moves east toward S. America preventing cold water from reaching the surface
This causes shifts in weather patterns
caused warm winter in northeastern US, heavy rains, flooding and mudslides in CA, and deadly tornadoes in FL
La Nina-A climate event in the eastern Pacific Ocean in which surface waters are colder than normal
Opposite of El Nino-colder than normal winters, greater precipitation to Pacific Northwest and the north central US.

6. Currents and Climate Deep Currents
Deep currents are caused by differences in the density of the ocean water
Move and mix water around the world
Carry cold water from the poles toward the equator
Move very slowly
Cold water is more dense than warm water
Increase salinity = increase density
How they form:
Warm water from equator
moves to the poles and cools
density increases)
Ice forms causing the salinity
of the water to increase
(density increases)
Water then sinks, flows along
ocean floor as a deep water current
Deep water currents are also
affected by the Coriolis effect.
Deep currents are like a conveyor belt moving water between the oceans
Bring needed oxygen to marine life living at the bottom of the ocean