Ocean+Currents-+Density++by+Mariana+and+Kam

=Density Currents:=

//**Density currents** result when water in an area of the ocean becomes denser than water around it. The denser water slips underneath the less dense water, forming what you call a density current.

-// **There are 3 common causes of currents:**

Evaporation -
the density of water in warm, dry climates.
 * affects:

salt in water is left behind and it increases salinity of water.
 * when sea water evaporates it causes:

a//s the salinity increases the density increases.//
 * Therefore:
 * for more information on salinity and why it increases the density** **click here**

Cooling -
the sea water in polar regions.
 * affects:

water to contract: - since it takes up less space the particles are crowded together. //crowded particles = increasing density.//
 * Causes:
 * Therefore:

Freezing:
affects: polar regions ( just like cooling)

as the ice freezes most of the salt is left behind along with the water. - increasing the density of the water that remains unfrosted.
 * How:

Density Currents by Evaporation:
In the Medditerranean Sea
 * Found:**

Hot, dry climate evaporates more water than the Medditerranean Sea receives. - leaves Medditerranean with higher salinity, and a higher density than ocean water.
 * How Does this event happen:**

This picture shows how denser water from the Mediterranean escapes into the Atlantic Ocean water making it so its water passes through the straight of Gibraltar, and then sinks under the currents of the Atlantic ocean.

Note: They are measuring the salinity by knots.( **view manny and matt's page for more info on salinity** )

Density Currents From Polar Water:
Most dense water in the oceans.
 * Why:** Because of intense cooling and freezing.

3 important water masses:
Coldest most dense water in the ocean.
 * Antarctic Bottom Water:**

Where: Weddell and Ross Seas off the coast of Antarctica. Temperature : -1.9 C
 * Salinity:** 34.6 ‰


 * //Deepest in three major ocean basins!!!//**

Second most dense water in the ocean.
 * North Atlantic Deep Water:**

Where: Near Greenland - Flows above it.
 * Temperature:** 3 C
 * Salinity:** 34.5 ‰
 * //Less dense than Antarctic Bottom Water.//**

Where: 55 S
 * Antarctic Intermediate Water:**
 * Temperature:** 2.2 C
 * Salinity:** 33.8 ‰
 * //The less dense of the three.//**

//**Upwelling:** occurs when cold deep water comes to surface.//

- California. (upwelling caused by: wind) - Other places where upwelling is caused by wind: Morroco, southwestern Africa, Peru, and western Australia.
 * Most Common:** On the western sides of continents.

Caused by wind + density currents.
 * Antarctic Ocean:**

- It contains plant nutrients ( phospates, silicates, nitrates ) that Phytoplankton need to grow. Phytoplankton = basic food of other living things in ocean. - Live in areas of upwelling. - Food for bigger fishes ( beggining of food chain) - Could affect Fishing today ( less fishing areas) - less sea food!!!!
 * Why is Upwelling Important?**

For More Information:
Begins On: pg. 348 and goes until pg. 451.**
 * Review Ch. 19, Section 2

The year has ended and I was really happy I joined the blue class. If I didnt I am sure I would have not met the great people I did. Thanks for making my first year in this amazing new town sweet. Hope to see ya next year, Kam S. 2010//**
 * //PS: Dont stress for the finals. Just study VERY HARD and do your best and I am sure that you will do great