They did this through measurements of magnesium content in the shells of microscopic sea surface animals found in ocean sediment.

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The Galapagos -- 19 islands that lie 600 miles west of Ecuador in the Pacific Ocean -- are home to species of animals found nowhere else on Earth.

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They act as grazers on the ocean floor (manatees are the only other animals that do this), helping keep a balance under the sea for other creatures to live and breed.

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After treatment, Dr. Kenney claimed that most animals were healthier at Sea World than they had been in the ocean.

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Since cesium binds to the sediment on the ocean floor, the radiation has likely had the biggest effect on bottom-dwelling fish and other animals though the consequences still aren't clear, said Tatsuo Aono, a specialist at Japan's National Institute of Radiological Sciences.

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