Diversity, ecology and age of endolithic cyanobacterial and algal communities from the Ross Desert, McMurdo Dry Valleys Antarctica
Zusammenfassung der Projektergebnisse
Endolithic cyanobacterial communities were found at all localities (McMurdo Dry Valleys [Mt. Falconer, Linnaeus Terrace, Granite Harbor, Battleship Promontory, Miers Valley, Garwood Valley] and the Brown Hill region at Darwin Glacier [Diamond Hill]) visited during these project, covering an altitudinal range from sea level to 1600 m a.s.l. and a latitudinal range between 76° and 80° south. They colonized almost every rock boulder larger than 80 cm in diameter being either of the granite or sandstone group or of calcite. Inside the rock they are activated either by melt water after rare snowfall events or, more regularly by condensation of dew from the air by reaching the dewpoint in the morning when the difference between rock surface and air is largest (-22 °). Radiocarbon dating indicates that activation frequency is highest at lower altitudes and latitudes. All endolithic communities are composed of a few species only, with a tendency of more species (pheno- and genotype based) in habitats of lower altitudes and latitudes. Relatively high biomasses (50 to 150 g/m² dry matter) are found in all habitats investigated except for the extremely dry Diamond Hill region, where we found high biomass but low chlorophyll a content. A surprise is certainly the discovery of the presence of biological soil crusts as far as 79°51’ south. In contrast to biological soil crusts from hot deserts and semi-deserts, but also to BSCs from the Arctic, they are composed of a few species only. Their coverage hardly reaches more than 3% of open soils and their photosynthesis cannot be activated by high air humidity alone, they need water in its liquid form to perform positive net photosynthesis. Nothing is known on their ecological role in the Antarctic terrestrial ecosystem. Biological soil crusts are known to stabilize soils against erosion, they leach carbon and nitrogen compounds into the soil. Especially in Antarctica, they may establish a peculiar but small biocoenosis in providing space and food for other organisms. Parts of our results were used for the ARTE productions “Die verletzliche Haut der Erde” und “The sensitive skin of the Earth”, first broadcasted in February 26th, 2011 and the ARD series “W wie Wissen: Klimaexpeditionen” broadcasted on Sunday 25th of November 2012.
Projektbezogene Publikationen (Auswahl)
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(2008). Dewfall as a water source frequently activates the endolithic cyanobacterial communities in the granites of Taylor Valley, Antarctica. Journal of Phycology 44: 1415-1424
Büdel, B., Bendix, J., Bicker, F., and Green, T.G.A.
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(2009). Cryptoendolithic cyanobacteria from calcite marble rock ridges, Taylor Valley, Antarctica. Algological Studies 129: 61-69
Büdel, B., Schulz, B., Reichenberger, H., Bicker, F., and Green, T.G.A.
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Biological soil crusts. In: COWAN, D. Antarctic Terrestrial Microbiology: Physical and Biological Properties of Antarctic Soils. Springer Verlag, 2014, pp 131-161.
Büdel, B. and Colesie, C.
