Archive for September 25th, 2007

Signs of the Apocolypse #885

1

fr0h.jpg

Frog-deforming infections caused by tiny parasites are increasing because of North American farms’ nutrient-rich watershed, a new study shows.

The excess nitrogen and phosphorus found in farm runoff causes more algae to grow, which increases snail populations that host microscopic parasites called trematodes, said Pieter Johnson, a water scientist at the University of Colorado in Boulder.

Deformed frogs first gained international attention in the mid-1990s, when a group of schoolchildren discovered a pond where more than half of the leopard frogs had missing or extra limbs, Johnson said. Since then, widespread reports of deformed amphibians have led to speculation that the abnormalities were being caused by pesticides, increased ultraviolet radiation or parasitic infection.

Parasite infection is now recognized as a major cause of such deformities, but the environmental factors responsible for increases in parasite abundance have largely remained a mystery.

“What we found is that nitrogen and phosphorus pollution from agriculture, cattle grazing and domestic runoff have the potential to significantly promote parasitic infection and deformities in frogs,” Johnson said.

from LiveScience.comĀ