Unusual fungal niches
Gunde-Cimerman, Nina , Zalar, Polona .
Extremotolerant indigenous mycobiota in Arctic subglacial ice.
Ice is an excellent matrix for long term preservation of microorganisms and also an extreme habitat for active microbial life. During freezing and binding of water in ice crystals ions are expelled in the remaining liquid water veins. These veins and liquid water at the base of polythermal glaciers provide still poorly understood and explored habitats for microbial life. Preventing the osmotic stress by media with lowered water activity and low incubation temperatures, we were the first to isolate surprisingly high number of fungi from melted subglacial ice of four different polythermal glaciers (Spitzbergen, Norway). Isolates were identified based on morphology, secondary metabolite profiles and molecular data. The majority of fungi were basidiomycetous yeasts, with Cryptococcus liquefaciens as the dominant species. Representatives of the genus Cladosporium and the ubiquitous, pleomorphic, halotolerant Aureobasidium pullulans were found particularly in ice containing precipitated gypsum crystals. The sediment-rich subglacial ice contained a very high occurrence and diversity of filamentous Penicillium spp., with P. crustosum as the dominant species. Multilocus analyses showed that most Arctic fungal isolates form distinct genotypes, which were later described as species or subspecies. Subglacial environments constitute a unique ecosystem, since they enable on the geological scale occasional enrichment of the most robust species, able to tolerate a broad range of temperatures and water activities. It seems that the dominant fungi are freeze-thaw resistant, halotolerant, relatively small-sized and have the ability to utilize a wide range of carbon and nitrogen sources. Glacier may represent a significant reservoir of so far overlooked biological activity with the potential to influence glacial melt-water composition, release of nitrogen and carbon in the polar environment and seeding of oceans with microbial life.
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1 - University of Ljubljana, Biotechnical faculty, Biology, vecna pot 111, Ljubljana, 1000, Slovenia
Presentation Type: Symposium or Colloquium Presentation
Location: Ballroom 1/Cliff Lodge - Level B
Date: Monday, July 27th, 2009
Time: 1:30 PM