Circular patterns growing on moss confuse scientists
http://www.knoxnews.com/kns/gs_news/article/0,1406,KNS_392_5569128,00.html

Circular patterns growing on moss confuse scientists
What's making the mini crop circles? Snails? Millipedes?
By MORGAN SIMMONS, simmonsm@knews.com
June 4, 2007

A mysterious circular pattern on moss-covered logs has scientists
scratching their heads.
Last winter, researchers in the Great Smoky Mountains National Park
discovered the symmetrical bull's-eye pattern on patches of liverwort (a
close relative of moss) growing on pine trees that had died and fallen
on the ground.
At this point, biologists aren't sure what causes the circles. Some have
suggested snails, while others have speculated millipedes.

"Immediately, we thought of snails," said Keith Langdon, chief biologist
with the Smokies. "But snails graze in a zigzag pattern. We can't find
records of anything like this in the park. It appears to be a rare
phenomenon."
Etched into the velvet-green surface of the liverwort, the patterns have
appeared like tiny crop circles. The only reports of anything similar
come from the arctic regions of Greenland and Canada, where a
moss-eating fungus is believed to be the cause.

So far, there are no known reports of the circular patterns occurring
this far south or on liverwort.
Chuck Parker is an aquatic biologist for the U.S Geological Survey who
spotted the circular patterns a few weeks ago on a cliff face in the Big
South Fork National River and Recreation Area.

"Finding them outside the Smokies, and on a substrate other than pine
trees, is a variation on the theme," Parker said. "There's a real
fascination here. I'd love to figure it out."
Rebecca Shiftlett is a nature photographer and art teacher who was with
the group that discovered the circles in the Smokies last winter. They
were surveying an area for the All Taxa Biodiversity Inventory (ATBI)
when they noticed some unusual impressions on liverwort-covered logs
beside the trail.

"When you've been in the woods as long as we have, you look for things
you've not seen," Shiftlett said. "These concentric circles jumped out
at us. We sat there for the longest time trying to figure out what in
the world would do that."
Since 2002, the ATBI has sent an army of researchers and volunteers into
the Smokies to collect and catalogue every living life form.
So far, the ATBI has identified approximately 4,666 species that are new
records for the park and 651 species new to science.

Shiftlett said the bull's-eye patterns are a perfect example of the
mysteries that are revealed when enough people start looking around.
"Nature tends to produce shapes that are organic and free form," she
said. "This clearly is a geometric pattern, which, in the natural world,
you hardly ever see."

Morgan Simmons may be reached at 865-342-6321.