Today's entry was written by Taisha:
Widely reported a few months ago, researcher Dr. Catherine La Farge and personnel from her lab at the University of Alberta recently documented the revival of bryophytes that had been buried under glacial ice. Radiocarbon dating of the mosses showed that the plants had been frozen since just prior to the Little Ice Age, approximately 400 to 615 years ago.
Today's photograph, provided by Dr. La Farge, shows Aulacomnium turgidum (or turgid aulacomnium moss) being revealed at the margin of the receding Teardrop Glacier in Sverdrup Pass on Ellesmere Island, Nunavut, Canada. From seven subglacial specimens sampled, 11 cultures displayed regrowth in the lab. The four taxa most consistently generated were Aulacomnium turgidum, Distichium capillaceum, Encalypta procera, and Syntrichia ruralis. For more on this story, see the news article from the University of Alberta, or read the journal article in PNAS: La Farge, C, et al. 2013. Regeneration of Little Ice Age bryophytes emerging from polar glacier with implications of totipotency in extreme environments. Proceedings of the National Academy of Sciences. 110(24):9839.
Dr. La Farge and her research team attributed the ability to revitalize the moss specimens that were entombed in ice for 400+ years to totipotency and poikilohydry. Totipotency means that a cell contains the mechanisms and information to divide and potentially differentiate into all of the ultimate cells of the organism (for humans, the zygote is an example). In mosses, totipotency in some (if not all) of the cells in the individual plant is a common phenomenon. Poikilohydry, or the ability to be dessicated and easily revived without physiological damage, is a strategy some bryophytes exhibit to adapt to irregular water supplies in their environment, like the high Arctic. Poikilohydric bryophytes typically lack mechanisms that control the gain and loss of water and consequently water may move in and out of the plant rapidly (see: Proctor, MC and Z. Tuba. Poikilohydry and homoihydry: antithesis or spectrum of possibilities? New Phytologist. 156(3):327-349).