Ocean Circulation 16.1

16.1 Ocean Circulation Ocean current is the mass of ocean water that flows from one place to another. Two types of ocean currents: Surface currents Density currents

1. Surface Currents Surface currents are movements of water that flow horizontally in the upper part of the ocean’s surface. • How do you think that a surface current develops?

Ocean Surface Currents Gyres = Clockwise rotation north of equator Gyres = Counter clockwise rotation south of equator Gyres are huge circular-moving current systems that dominate the surfaces of the oceans

Coriolis Effect The Coriolis effect is the deflection of currents away from their original course as a result of Earth’s rotation.

2. Density Currents Density currents are deep water currents that occur below the surface currents. Density currents move vertically. Density currents occur in cold, salty water. Surface currents Density currents

The Composition of Seawater The Ocean Conveyor Belt moderates earth’s climate. • When currents from equator move into north and south poles, they transfer heat from warmer to cooler areas on Earth. • As cold water currents from north and south poles travel toward the equator, they help moderate warm temperatures of adjacent land areas. Equator Red = warm water Blue = cold water

The Composition of Seawater A Conveyor Belt • In a simplified model, ocean circulation is similar to a conveyor belt that travels from the Atlantic Ocean, through the Indian and Pacific Oceans, and back again.

The Composition of Seawater 1. Upwelling is the rise of cold water from deeper layers to replace warmer surface water. 2. Upwelling brings greater concentrations of dissolved nutrients, to the ocean surface.

Effects of Upwelling Makes no sense without caption in book

El Nino Normal Year Offshore winds Good fishing El Nino Year Rain Poor fishing