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."
What was going on in that water in the Ney Pond is still largely a mystery.
Parasites were found in the pond, but they're not likely to explain all the deformities because they usually produce multiple legs, and most deformities show up as missing legs.
Drain tiles leading into the pond from nearby farm fields could carry fertilizer and pesticides, but it's very difficult to isolate which chemical might be the culprit, because chemicals break down and form new compounds which are hard to reproduce in the lab.
These complications turned out to be all too common at the other deformed frog hot-spots around the world.
Helgen's quest was made more difficult because she felt she didn't have the support of her bosses at the MPCA. She said they resisted asking the legislature for money because they thought it might endanger funding for other projects.
"There's a way that the state agencies do their budgets," she said. "They do priority planning way ahead, and the frogs popped up after they had set their priorities."
The legislature did provide money for several years, and Helgen coordinated a loose group of researchers from many fields in various parts of the country. She concentrated on collecting samples at the many locations she learned about from concerned citizens.
"Every year we didn't know if we'd be allowed to go back and work on it further," she said. "So my feeling was we were just trying to document the sites that had deformed frogs so they'd be available to other researchers."
The deformities emerged after a period of sudden and dramatic declines in populations of amphibians all over the world. Estimates differ, but some scientists say as many as 120 species of amphibians may have become extinct in the 1980s, and perhaps one-third of amphibians are at risk of extinction today.
It's not clear whether the population declines are linked to the deformities. Many experts believe habitat loss is the biggest cause of declining frog populations.
The U.S. Fish and Wildlife Service is completing its research on amphibians at wildlife refuges around the country, and a report is due in a couple of weeks. It's expected to show continuing outbreaks of deformed frogs.
Helgen said hope for wetlands and the creatures that inhabit them rests in the younger generation -- like the children who visit the Ney Nature Center.
"If the kids grow up to be active adults who want to have good science done and really want to have species protected -- those two things -- I think they could make a difference."