Light reaches deep in southeast Pacific

1:53pm, July 30, 2007

An oceanographic survey of the southeastern Pacific has discovered a region where ultraviolet radiation penetrates deeper than has been measured in any other ocean locale.

Sunlight streaming onto the ocean's surface is either absorbed by water molecules or dissolved substances, or else scattered sideways when it reflects off objects such as microorganisms. In ocean regions teeming with life, 90 percent of the light at certain ultraviolet wavelengths is blocked before it reaches a depth of 3 meters, says Richard Sempéré, a marine biogeochemist at the University of the Mediterranean in Marseilles, France.

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