Very Clear Ocean Water

What is this thing? Today, we are out in a part of the South Pacific Ocean where there is very little ocean life. This is because there is very little food available. As you know, water is clear in color but ocean water has some coloring to it due to several things. Tiny organisms called phytoplankton often give the water a bit of a greenish color and the reflection of the sky gives it a blue color. Out here in this part of the ocean, the lack of organisms means the water is very clear. Yesterday, some of the scientists lowered a Secchi disk, on a string, into the water. A Secchi disk is a flat circle painted with black and white sections. When the Secchi disk can no longer be seen through the water, the length of the string is measured. That tells us how clear the water is. The disk "disappeared" at a depth of 147 feet!

The ocean water flows around the edge of the South Pacific Ocean in a huge slow moving motion called a gyre. In the southern hemisphere, the movement is counterclockwise. Each ocean basin has an ocean gyre. We are in the center of the South Pacific Gyre. On the simplest terms, this is why there is so little ocean life here.