Earth’s Oceans They are considered separate oceans because water in these regions follow a particular pattern and behavior.

What is a current? A word that describes the movement of water

Surface Currents These are currents that are on the top layer of the ocean (up to several hundred meters deep). They are caused mainly by the wind that occurs at the ocean’s surface.  They are also controlled by the Coriolis effect and continental deflections.

Global Winds Winds that blow across the Earth’s surface  The force of these winds move the water  Different winds cause currents to flow in different directions  Winds near the equator move east to west  Winds near the poles move west to east

Coriolis Effect The apparent curving of the path of a moving object from an otherwise straight path due to the Earth's rotation.

Continental Deflection If the earth’s Surface were covers completely in water, the currents would travel freely across the globe in a very uniform pattern. Well we have huge land masses on our Earth called continents.  When surface currents meet continents, the currents deflect, or change direction.

Currents are Affected by Temperature Warm-water currents begin near the equator and carry warm water to other parts of the ocean. Cold-water currents begin closer to the poles and carry cold water to other parts of the ocean.

Gyres – A ring like system of ocean currents

Deep Ocean Currents A stream like movement of water FAR below the surface.

Deep Ocean Currents Formed in parts of the ocean where water density changes.  The density of the ocean water is affected by temperature and salinity  The colder the water is…the more dense  The more salt in the water… the more dense the water is

Deep Ocean Currents Denser Denser (Colder and higher salinity levels) water sinks!

How this works… poles Surface currents carry the warmer, less-dense water from other ocean regions to the poles. sinks Once the temperature gets colder and the salinity levels increase, the water becomes more dense and sinks ocean floor Deep ocean currents carry the cold, dense water across the ocean floor from polar regions to other regions in the ocean less denserises Once the water warms and its salinity levels decrease, it becomes less dense and rises.

Warm Water Currents and Climate Warm surface currents create warmer regions in coastal areas that would otherwise be much colder.

Cold water currents and Climate Cold Surface currents create colder climates in coastal areas that would otherwise be much warmer.

Upwelling Upwelling -The movement of deep, cold, and nutrient-rich water to the surface. This happens along coasts, and when this happens it creates animal diversity.

Upwelling Phytoplankton use these nutrients to grow and reproduce at rapid rates. This attracts organisms to areas of upwelling that rely on phytoplankton as food and, in turn, attracts their consumers. This area is rich in biological activity and diversity. Approximately half of the fish caught in the world come from areas where upwelling occurs.

El Niño - Unusually warm surface water temperatures in the Pacific ocean caused by weak or reversed direction trade winds.

La Niña - Unusually cold surface water temperatures in the Pacific ocean caused by strong easterly trade winds.

El Niño and La Niña simplified… El Nino is the abnormal heating of Earth’s ocean surface in the Pacific. La Nina is the abnormal cooling of Earth’s ocean surface in the Pacific.

Causes: El Nino El Nino is caused when WEAK trade winds allow warm water from the Pacific to flow east. This builds up warm surface water that will soon cause the El Nino. La Nina La Nina is caused when the temperatures drop in the pacific, also being blown east from STRONG winds. This builds up cold surface water at the coasts and will cause a La Nina.

What causes an El Niño? Weak trade winds and weak upwelling cause warm surface water

What causes a La Niña? Strong trade winds and strong upwelling blow surface water towards east, creating colder surface temperatures.

Occurrence El Nino El Nino’s occur on average during the summer time when it’s warm. Can last for a year or longer They normally happen randomly, but most have destruction during the summer. La Nina La Nina occurs on average in the winter when it’s cooler Can last 9-12 months They also happen randomly, but cause the most damage in winter. El Nino La Nina. Oracle Think Quest. Retrieved May 14th,

Effects of El Nino and La Nina z Alters normal weather patterns y Flash floods y Mudslides y Droughts z Crazy weather patterns affects crops z Decreases upwelling so less organisms