Following Ocean Drifters Around the Pacific

Where Does the River's Trash Go?

1Every spring, the Cascade Creek Watershed Club at Rivermont Middle School in Oregon picks up trash along a creek that flows into a large river and then into the Pacific Ocean. This year, club member Selin Aydın asked a question nobody could answer: where does floating trash go once the river carries it out to sea? Her teacher, Mr. Ikaika Kealoha, found an ocean research program that tracks GPS drifters. A drifter is a floating buoy that moves with the surface current and reports its position by satellite.

2Sunlight heats Earth unevenly. Near the equator it strikes the surface most directly, and near the poles it arrives at a low slant. These differences in heating set up large belts of wind. Between the equator and about 30° latitude, the trade winds blow mostly from the east toward the west. Between about 30° and 60° latitude, the westerlies blow mostly from the west toward the east. Steady winds drag the ocean's surface water along with them, forming surface currents.

3Because Earth spins, air and water that travel long distances over its surface are bent off a straight path. In the Northern Hemisphere, they turn toward the right of the direction they are moving. In the Southern Hemisphere, they turn toward the left. When a current runs into a continent, the land turns it aside.

4Currents also carry heat. A current flowing away from the tropics carries warm water, and a current flowing from near the poles carries cool water. Cool water cools the air just above it. Cool air near the surface tends to stay low instead of rising, so clouds and rain form less often over it.

5The program released Drifter A off the coast of Oregon. A partner school in Chile helped release Drifter B off the coast of central Chile on the same day. In the tables, °N means north of the equator and °S means south of it. A larger °W number means farther west.