May 28, 2013
Plants Reawaken After 400 Years Buried Under Canadian Glacier
Lawrence LeBlond for redOrbit.com - Your Universe Online
A Canadian scientist has discovered that certain once-frozen plants have the ability to reawaken after long periods of dormancy, sprouting back to life.The finding came while Catherine La Farge, a researcher with University of Alberta´s Faculty of Science, was observing ancient plants known as bryophytes in the Canadian tundra. Recently exposed terrain left behind by receding glaciers has revealed a startling awakening of these bryphytic organisms.
La Farge, who is also director and curator of the Cryptogamic Herbarium at Alberta, has now overturned the long-held assumption that all plant remains buried under glaciers for centuries (or longer) are unable to regrow once glaciers retreat. Previously, all new growth of plants near the margins of the receding icepack was believed to be the result of rapid colonization by modern plants near glaciers.
But as La Farge and her colleagues studied the plant life more closely around Teardrop Glacier on Sverdrup Pass in the High Canadian Arctic, they discovered that the bryophytes, which ranged from 400 to 600 years old, had been entombed during the Little Ice Age that occurred between 1550 and 1850. With glaciers receding, the team noticed that these subglacial populations were not only intact, but were in pristine condition and growing.
The Teardrop Glacier has been receding at a fairly steady rate of 10 to 13 feet per year since 2004, exposing land that has not seen the light of day for more than 4 centuries.
"We ended up walking along the edge of the glacier margin and we saw these huge populations coming out from underneath the glacier that seemed to have a greenish tint," La Farge told BBC News.
Bryophytes are much different than typical land plants, having no vascular tissue to help pump fluids throughout the organism. While they are known to survive long Arctic winters, returning to growth in the warmer months, the study team was shocked to see bryophytes long-entombed in ice come to life.
"When we looked at them in detail and brought them to the lab, I could see some of the stems actually had new growth of green lateral branches, and that said to me that these guys are regenerating in the field, and that blew my mind," she said.
The growth seen around the retreating ice also included cyanobacteria and green terrestrial algae. La Farge said many of the species they discovered here are entirely new to science.
"It's a whole world of what's coming out from underneath the glaciers that really needs to be studied," La Farge said. "The glaciers are disappearing pretty fast - they're going to expose all this terrestrial vegetation, and that's going to have a big impact."
La Farge and her team collected samples and returned them to the lab in Alberta. The team, with the help of master´s student Krista Williams, selected 24 samples for culture experiments. Seven of the samples produced 11 cultures that successfully regenerated four species from the original plant material.
“These simple, efficient plants, which have been around for more than 400 million years, have evolved a unique biology for optimal resilience,” explained La Farge. “Any bryophyte cell can reprogram itself to initiate the development of an entire new plant. This is equivalent to stem cells in faunal systems.”
La Farge noted that this discovery intensifies the critical role of bryophytes in polar environments and has implications for all permafrost regions around the world.
“Bryophytes are extremophiles that can thrive where other plants don´t, hence they play a vital role in the establishment, colonization and maintenance of polar ecosystems. This discovery emphasizes the importance of research that helps us understand the natural world, given how little we still know about polar ecosystems–with applied spinoffs for understanding reclamation that we may never have anticipated,” La Farge said in a University of Alberta statement.
In an interview with IO9´s Joseph Bennington-Castro, La Farge said she hopes their work will renew interest in bryophytes, which haven´t been widely studied in botany.
“I think the whole biological system of bryophytes has not really been understood well," she told Bennington-Castro. But she said her team´s (i.e.) research has shown that bryophytes are able to “shut down” and remain dormant for centuries, only to return to life when the conditions are right.
By studying bryophytes and their regenerative powers further, scientists may be able to get a better understanding of the basic systems of life and potentially may be able to transfer such knowledge to promoting biological development in otherwise barren landscapes.
In fact, bryophyte research could lead to promotion of biological development on extraterrestrial worlds. "Maybe astronauts would want to take bryophytes to other planets to see if they would grow and how they could modify extraterrestrial landscapes," La Farge told Bennington-Castro.
A paper on La Farge's work is published in the journal PNAS.