Arctic gypsum endoliths: a biogeochemical characterization of a viable and active microbial community

摘要: Extreme environmental conditions such as those found in the polar regions on Earth are thought to test limits of life. Microorganisms living these environments often seek protection from stresses high UV exposure, desiccation and rapid temperature fluctuations, with one protective habitat within rocks. Such endolithic microbial communities, which consist bacteria, fungi, algae lichens, small-scale ecosystems comprised both producers consumers. However, harsh experienced by communities limit diversity therefore rate at they cycle carbon. In this study, we characterized community diversity, turnover microbe–mineral interactions a gypsum-based desert Canadian Arctic. 16S/18S/23S rRNA pyrotag sequencing demonstrated presence diverse phototrophic heterotrophic archaea, fungi. Stable carbon isotope analysis viable membranes, phospholipid fatty acids glycolipid acids, confirmed observed molecular techniques indicated that present-day atmospheric is assimilated into biomass. Uptake radiocarbon nuclear weapons testing during 1960s lipids was used pulse label determine turns over order 10 yr, equivalent 4.4 g C m −2 yr −1 gross primary productivity. Scanning electron microscopy (SEM) micrographs mechanical weathering gypsum freeze–thaw cycles leads increased porosity, ultimately increases habitability rock. addition, while bacteria were adhered mineral surfaces, chemical micro-X-ray fluorescence (μ-XRF) spectroscopy suggests little evidence for alteration minerals, contrasts other habitats. While it possible turn quickly leave interaction, an alternative hypothesis soluble friable nature lead elevated erosion rates, limiting residence times habitat. Regardless, represents system does not rely nutrient pool host cap rock, instead receiving elements allochthonous debris maintain more active than might have been predicted