by Piter Kehoma Boll
Bipolar and Alpine in distribution, occurring in both Arctic and Antarctic regions, as well as on the Alps and nearby temperate areas, the elegant sunburst lichen (Xanthoria elegans) is a beautiful and interesting creature. As all lichens, it is formed by a fungus associated with an alga.
The elegant sunburst lichen grows on rocks and usually has a circular form and a red or orange color. Growing very slowly, at a rate of about 0.5 mm per year, they are useful to estimate the age of a rock face by a technique called lichenometry. By knowing the growth rate of a lichen, one can assume the lichen’s age by its diameter and so determine the minimal time that the rock has ben exposed, as a lichen cannot grow on a rock if it is not there yet, right? This growth rate is not that regular among all populations. Lichens growing closer to the poles usually grow quickly because they seem to have higher metabolic rates to help them survive in the colder climates.
Beside its use to determine the age of a rock surface, the elegant sunburst lichen is a model organism in experiments related to resistance to the extreme environments of outer space. It has showed the ability to survive and recover from exposures to vacuum, UV radiation, cosmic rays and varying temperatures for as long as 18 months!
Maybe when we finally reach a new inhabitable planet, we will find out that the elegant sunburst lichen had arrived centuries before us!
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Murtagh, G. J.; Dyer, P. S.; Furneaux, P. A.; Critteden, P. D. 2002. Molecular and physiological diversity in the bipolar lichen-forming fungus Xanthoria elegans. Mycological Research, 106(11): 1277–1286. DOI: 10.1017/S0953756202006615
Wikipedia. Xanthoria elegans. Available at: < https://en.wikipedia.org/wiki/Xanthoria_elegans >. Access on June 30, 2016.
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