from far away. Transport was probably by wind as there is no flowing water in the region. Mount Melbourne was recently active, has a polar night lasting thirteen weeks, has soils containing toxic elements such as mercury, is distant from ecosystems that could be the source of colonization events, and lies away from the westerlies, which may explain why the vegetation is species-poor. Pohlia nutans may have arrived only recently on Mount Melbourne, or this volcano is not as favourable for its growth as Mount Rittmann, where this moss is more common. Its colonies are less vigorous on Mount Melbourne than Campylopus pyriformis. Condensing fumarole gases and meltwater from snow form the water supply of this vegetation. Mosses are concentrated around fumarolic vents as there is more fresh water available there. The steam freezes in the cold air, forming the ice hummocks that act as a shelter and maintain stable humidity and temperature. The geothermal heating and the availability of freshwater sets these volcanic biological communities apart from other Antarctic vegetation communities that are heated by the sun. Some bacterial species are nitrogen fixing. Genetic analysis has found that some mosses at Mount Melbourne are mutating, yielding genetic variation. The hot, wet soils at Mount Melbourne host thermophilic organisms, making Mount Melbourne an island of thermophilic life on an ice-cold continent. Cold-tolerant microbes coexist with the thermophiles. Other species associated with the vegetation are the protozoan Corythion dubium, which is a testate amoeba common in Antarctica and the only invertebrate found in the geothermal habitats of Mount Melbourne, actinobacteria and various actinomycetes and fungal genera. Several bacterial species were first described from Mount Melbourne's geothermal terrains: Alicyclobacillus pohliae from the northwest slope. Aneurinibacillus terranovensis from Cryptogam Ridge and also from Mount Rittmann volcano. Bacillus fumarioli from Cryptogam Ridge. Bacillus thermoantarcticus from Cryptogam Ridge, later renamed to Bacillus thermantarcticus. A further reclassification to Geobacillus thermantarcticus was proposed in 2012. Brevibacillus levickii from the northwest slope. See also List of Ultras of Antarctica List of volcanoes in Antarctica Notes References Sources Further reading External links "Mount Melbourne, Antarctica" on Peakbagger Melbourne, Mount Borchgrevink Coast Antarctic Specially Protected Areas