University of Alberta researchers led by Dr Catherine La Farge have brought back to life 400 year old frozen mosses recovered from melting glaciers in the High Canadian Arctic.
The result, reported in the Proceedings of the National Academy of Sciences, overturns a long-held assumption that all of the plant remains exposed by retreating polar glaciers are dead. Previously, any new growth of plants close to the glacier margin was considered the result of rapid colonization by modern plants surrounding the glacier.
Dr La Farge’s team using radiocarbon dating confirmed that the plants, which ranged from 400 to 600 years old, were entombed during the Little Ice Age that happened between 1550 and 1850.
In the field, the scientists noticed that the subglacial populations were not only intact, but also in pristine condition – with some suggesting regrowth.
They then selected 24 subglacial samples for culture experiments. Seven of these samples produced 11 cultures that successfully regenerated four species from the original parent material, including the turgid aulacomnium moss Aulacomnium turgidum and the moss Distichium capillaceum.
“The re-growth of these Little Ice Age bryophytes (such as mosses and liverworts) expands our understanding of glacier ecosystems as biological reservoirs that are becoming increasingly important with global ice retreat,” Dr La Farge said.
“We know that bryophytes can remain dormant for many years and then are reactivated, but nobody expected them to rejuvenate after nearly 400 years beneath a glacier.”
“These simple, efficient plants, which have been around for more than 400 million years, have evolved a unique biology for optimal resilience. Any bryophyte cell can reprogram itself to initiate the development of an entire new plant. This is equivalent to stem cells in faunal systems.”
Dr La Farge said: “the finding amplifies the critical role of bryophytes in polar environments and has implications for all permafrost regions of the globe.”
“Bryophytes are extremophiles that can thrive where other plants do not, 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 spin-offs for understanding reclamation that we may never have anticipated.”
Bibliographic information: Catherine La Farge et al. Regeneration of Little Ice Age bryophytes emerging from a polar glacier with implications of totipotency in extreme environments. PNAS, published online before print May 28, 2013; doi: 10.1073/pnas.1304199110