Marine Environment

Why is Ocean Circulation Important? Transport ~ 20% of latitudinal heat from the equator to the poles Transports nutrients and organisms in important upwelling areas Influences weather and climate Influences commerce (economy)

Types of Currents Two main types of currents: (1) surface currents – driven by wind (2) deep water currents – driven by density and gravity

-17 major surface currents that move quickly How fast? A few miles/hr (Gulf Stream off of Miami = 4.5 mph) How much? Total water in ocean surface circulation = about 100 Amazon Rivers (20 million m3/s).

Global Conveyor Belt The surface and deep water currents work together to transfer solar radiation from the equator to the poles and helps moderate Earth’s climate Deep water currents are colder and higher in salinity, which keeps the currents in deep water Surface water currents are warmed by the sun and are less dense because they contain lower levels of salinity The surface and deep water currents work together to create the “Global Conveyor Belt”

Upwelling Winds push surface water offshore Deeper water moves upward to replace the displaced surface water Deeper water brings nutrients (phosphorus and nitrogen) up with it to create plankton blooms

Gyres Gyres are closed systems of circulating water The winds blowing from the east are called the Trade Winds. The winds blowing from the west are called Westerly Winds. These opposing wind systems contribute to the formation of  gyres.