HENDERSON — Seventeen years ago next month, school children made a gruesome discovery in south-central Minnesota.
In the Ney Pond, an ordinary pond surrounded by cornfields and woods near Henderson, they found dozens of deformed frogs.
More than half were grotesquely missing legs or had extra legs, ones that branched and multiplied.
"It was terrible," said Judy Helgen, a biologist for the Minnesota Pollution Control Agency. "The kids and the parents, everybody looked really worried."
The discovery was the first of an alarming series of finds in Minnesota and other states and Canada, one that focused scientists' attention on wetlands.
Researchers still don't know why most of these outbreaks occur. But they've made some progress in identifying possible causes, among them chemicals or pesticides in the soil, parasites or too much ultraviolet light.
Helgen and expert on wetlands who helped search for what deformed the frog, tells the story of the investigation in a new book, "Peril in the Ponds -- Deformed Frogs, Politics, and a Biologist's Quest," published by University of Massachusetts Press.
In August, 1995, she came to the Ney Pond, which is part of a nature center, to see what was happening. The visit took her life in a new direction, one that would involve several years working evenings and weekends to do two jobs -- her normal work on wetlands health, and detective work on deformed frogs.
For Helgen, the frogs were important, as could help people recognize the value of wetlands.
"I didn't think people were really understanding that wetlands are so important in supporting aquatic life," she said. "You look at a pond and maybe see a couple ducks on it but you don't really know what's going on in the water."