"Nutrient Runoff Deforming Frogs"

"Nutrient Runoff Deforming Frogs," on CNN.com

Researchers have discovered the nitrogen and phosphorus in the runoff from farms and ranches contribute to deformities in frogs, such as extra limbs or loss of legs, by creating an environment in which more infectious parasites will grow.

"Here's how the cycle works: The parasites, called trematodes, have a series of host species.They grow in snails and become infectious when released by the snails into ponds, where they can infect frog tadpoles, forming cysts in the developing limbs. Water birds eat the frogs and then excrete the parasites back into the ecosystem where they can infect the snails, he explained."

The complete research report, "Aquatic Eutrophication Promotes Pathogenic Infection in Amphibians," appeared September 24, 2007 in the online edition of the Proceedings of the National Academy of Sciences.

Keywords: eutrophication (decline of life-sustaining capabilities due to nitrogen and other fertilizers), amphibians, trematodes, deformities

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