Park Leads the World in Science of ‘Water Bears’

Park Leads the World in Science of ‘Water Bears’

By Aaron Searcy

When Dr. Paul Bartels takes a walk in the woods, he sees a landscape absolutely teeming with bears. You’ll just need a microscope to see the ‘bears’ he has in mind.

“They occur in moss and lichen on trees and rocks,” said Bartels. “They’re also in soil, in leaf litter, and stream sediment and periphyton—the green stuff that forms on rocks and plants in most bodies of water.”

Claxtonia mauccii. Scanning electron microscopy by Dr. Diane Nelson, East Tennessee State University.
Claxtonia mauccii. Scanning electron microscopy by Dr. Diane Nelson, East Tennessee State University.

As an invertebrate zoologist and professor at Warren Wilson College, Bartels studies microscopic water bears, also known as tardigrades. Water bears are incredibly hardy and incredibly small animals with eight legs that can live just about anywhere, from the Arctic, to the equator, to the bottom of the sea. Some species are known for their remarkable ability to enter an extreme state called ‘cryptobiosis,’ in which most life processes are put on pause until environmental conditions improve.

Scientists chose the lush landscape of Great Smoky Mountains National Park to conduct one of the world’s largest systematic inventories of tardigrades to date. Photo by Shawn Clifford.
Scientists chose the lush landscape of Great Smoky Mountains National Park to conduct one of the world’s largest systematic inventories of tardigrades to date. Photo by Shawn Clifford.

Between 2000 and 2010, Bartels and his students at Warren Wilson College in Swannanoa, North Carolina, completed one of the largest systematic inventories of tardigrades ever conducted as part of the All Taxa Biodiversity Inventory project in Great Smoky Mountains National Park. That inventory, orchestrated in coordination with park partner Discover Life in America (DLiA), revealed a practically unexplored world of microscopic life humming away just beneath the realm of the humanly visible.

“The Smokies are now one of the best-known locations anywhere on earth for tardigrade fauna,” said Bartels. “When we got started, there was only one published paper that had reported just three species. Now, we’re up to a total of 85 species.” Eleven of those species have been officially described as species new to science, and Bartels suspects that more than twice that will eventually be proven to be new species as new data is obtained.

Water bears can be found in relative abundance in so many different places that the first challenge to studying them is simply deciding where to begin. Starting with a nearly blank slate in 2000, Bartels and his students working in the Smokies decided to use some of the park’s existing research plots to document and compare tardigrades across a range of forest types.

“In the end, we collected about 900 samples across the park and over 16,000 separate specimens,” said Bartels. ”Once the researchers returned to the lab, they began the tedious job of isolating those specimens from their surroundings and mounting them on slides—each sample requiring hours of work in a process Bartels describes as occasionally “overwhelming.”

The results of that meticulous work, however, are invaluable to scientists everywhere. In the process of their study, Bartels and his students created their own key to identifying and classifying tardigrades that can be used by future researchers who may want to work with this little-known group of animals.

Paramacrobiotus tonollii. Scanning electron microscopy by Dr. Diane Nelson, East Tennessee State University.
Paramacrobiotus tonollii. Scanning electron microscopy by Dr. Diane Nelson, East Tennessee State University.

“The reason I study tardigrades and got involved in the Smokies inventory in the first place is because they are such a vivid example of the extent of our ignorance of biodiversity,” said Bartels. “People think scientists have already discovered everything there is to know, and nothing could be further from the truth. There are uncharted wonders we can’t even see, and they are right here in our own backyard.”

Though public awareness and interest in water bears has grown rapidly since Bartels first began his work in the Smokies, much basic science remains to be done when it comes to understanding this particular branch of the tree of life and how it contributes to the health of ecosystems as a whole. Researchers are also particularly interested in understanding tardigrades’ cryptobiotic processes, which could potentially be applied toward developing technologies to preserve cells or tissues.

For even one of the world’s foremost authorities on the subject, the process has been humbling.

“After 20 years of exploration,” said Bartels, “we’ve really just barely scratched the surface.”

Bartels will be sharing more about water bears in the Smokies and beyond on Friday, August 20, as a featured speaker at DLiA’s Science at Sugarlands educational series. Registration for the free online event is currently available at dlia.org/sas.

Related Posts
  1. The Mysteries of Gregory Bald The Mysteries of Gregory Bald “In this Park, we shall conserve these trees, the pine, the red-bud, the dogwood, the azalea…for the happiness of the American people.” - President Franklin D. Roosevelt, from his speech dedicating Great Smoky Mountains National Pa
  2. Please don't pick our wildflowers Please don't pick our wildflowers
  3. Linnaea borealis, found—then lost Linnaea borealis, found—then lost The year 1934 – when Great Smoky Mountains National Park was officially established – was a dark year for Tennessee botanists. The gloom was due not to the creation of the park, which provided a permanent home for thousands of species of
  4. Pollinator garden dedication marks first of DLIA talk series at Sugarlands Pollinator garden dedication marks first of DLIA talk series at Sugarlands Discover Life in America dedicated the pollinator garden at Sugarlands Visitor Center on May 18 and kicked off its Science at Sugarlands series, a collection of talks to be held the third Friday of each month through October. A collaboration between
Related Products