Ocean Currents The Reality of Sending a Message in a Bottle

Why is Ocean Circulation Important? Transport heat –Equator to poles Transport nutrients and organisms Influences weather and climate Influences commerce

Convection cell model Non-rotating Earth Cold water coming from the POLES Warm water flows from The tropics THE EQUATOR

Add rotation and add landmasses unequal heating and cooling of the Earth

Two Types of Currents Surface Currents Wind Driven Deep Ocean Currents Density Driven

Surface Currents Flow across the surface to a depth of a few hundred meters Deep Water Currents Flow near the ocean floor below the waters surface Ocean Currents

Surface Currents Main Causes 1.Solar Heating (temp, density) 2.Winds- main cause of currents you see on the surface (Global winds) 3.Coriolis- rotation 4.Continental Deflection

Wind-driven surface currents

Sailors have know about ocean currents for centuries Sailors have know that “rivers” flow in the seas since ancient times. They used them to shorten voyages, or were delayed by trying to stem them. If navigators do not correct to deflection by currents, they may be far away from where they think they are and meet disaster.

What do Nike shoes, rubber ducks, and hockey gloves have to do with currents?

Lost at Sea

Barber’s Point

DEEP CURRENTS form when… Warm and cold surface currents meet and mix Result from differences in temperature and DENSITY COLD WATER=DENSE HEAVY= pushes down to the bottom Not Wind Driven!! Temperature/Density Driven

Surface and Deep-Sea Current Interactions Unifying concept: “Global Ocean Conveyor Belt”

“Great Pacific Garbage Patch” Estimate: 46,000 pieces of floating garbage/mi 2. North Pacific Subtropical Gyre

135° to 155°W and 35° to 42°N

North Pacific Subtropical Gyre YOUTUBE

1.What is a convection cell? 2.Why don’t currents travel in straight lines? 3.How are surface currents created? 4.What is a gyre? 5.How are deep currents created? Inquiry