Covering about seventy percent of the Earth's surface, the Oceans are central to the continued existence of life on our planet. The Oceans are where life first appeared on Earth. The largest creatures On Earth (whales) and the smallest (bacteria and viruses) live in the oceans. We rely on the ocean for many things, including food: water transportation, recreation, minerals, and energy. Oceans store energy. When ocean currents change, they cause changes in global weather patterns and can cause droughts, floods, and storms.

However our knowledge of our oceans is limited. Ships, coastlines, and islands provide places from which we can observe, sample, and study small portions of Oceans. But we can only look at a very small part of the global ocean this way. We need a better place from which to study oceans.

Space provides this place. Satellites circling the Earth can survey an entire Ocean in less than an hour. These satellites can "look" at clouds to study the weather, or at the sea surface (when it's not cloudy) to measure the sea's surface temperature, wave heights, and direction of waves. Some satellites use radar to "look" through the clouds at the sea surface.

One other important characteristic that we can see from space is the color of the ocean. Changes in the color of ocean water over time or across a distance on the surface provide valuable information.

SeaWiFS Teacher's Guide and Activities

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gene carl feldman (301) 286-9428