Isotopic evidence for the provenance and turnover of organic carbon by soil microorganisms in the Antarctic dry valleys

Hopkins, D. W.; Sparrow, Ashley D.; Gregorich, E.G.; Elberling, Bo; Novis, Phil M.; Fråser, F C; Scrimgeour, C. M.; Dennis, Paul G.; Meier‐Augenstein, Wolfram; Greenfield, L. G.

doi:10.1111/j.1462-2920.2008.01830.x

Cited by 64 publications

(82 citation statements)

References 71 publications

(121 reference statements)

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“…Therefore, we propose that they act as a reservoir for terrestrial microbiota. This notion is supported by recent isotopic evidence indicating that some organic matter in Dry Valleys soils remote from sources of liquid water has an endolithic origin (36). Weathering of sandstone is accelerated by endolithic colonization (10), and therefore, can be envisaged to disperse endolithic taxa, although in a relatively slow manner.…”

Section: Discussionmentioning

confidence: 82%

Highly specialized microbial diversity in hyper-arid polar desert

Pointing¹,

Chan²,

Lacap³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

347

413

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The McMurdo Dry Valleys in Antarctica are a cold hyperarid polar desert that present extreme challenges to life. Here, we report a culture-independent survey of multidomain microbial biodiversity in McKelvey Valley, a pristine example of the coldest desert on Earth. We demonstrate that life has adapted to form highly-specialized communities in distinct lithic niches occurring concomitantly within this terrain. Endoliths and chasmoliths in sandstone displayed greatest diversity, whereas soil was relatively depauperate and lacked a significant photoautotrophic component, apart from isolated islands of hypolithic cyanobacterial colonization on quartz rocks in soil contact. Communities supported previously unreported polar bacteria and fungi, but archaea were absent from all niches. Lithic community structure did not vary significantly on a landscape scale and stochastic moisture input due to snowmelt resulted in increases in colonization frequency without significantly affecting diversity. The findings show that biodiversity near the cold-arid limit for life is more complex than previously appreciated, but communities lack variability probably due to the high selective pressures of this extreme environment.

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Section: Discussionmentioning

confidence: 82%

Highly specialized microbial diversity in hyper-arid polar desert

Pointing¹,

Chan²,

Lacap³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

347

413

View full text Add to dashboard Cite

show abstract

“…We further propose expansion and extension of isotope approaches, which have been used in both High Arctic and Antarctic environments previously (Hopkins et al 2009;Lyons et al 2013), in order to shed light on the biogeochemical responses of Arctic and Antarctic cyanobacteria. Simulation studies, testing how changes in atmospheric CO 2 and temperature affect cyanobacterial populations, would help us to understand how these phyla may evolve in situ.…”

Section: Discussionmentioning

confidence: 99%

Ecology and biogeochemistry of cyanobacteria in soils, permafrost, aquatic and cryptic polar habitats

et al. 2015

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Polar Regions (continental Antarctica and the Arctic) are characterized by a range of extreme environmental conditions, which impose severe pressures on biological life. Polar cold-active cyanobacteria are uniquely adapted to withstand the environmental conditions of the high latitudes. These adaptations include high ultra-violet radiation and desiccation tolerance, and mechanisms to protect cells from freeze-thaw damage. As the most widely distributed photoautotrophs in these regions, cyanobacteria are likely the dominant contributors of critically essential ecosystem services, particularly carbon and nitrogen turnover in terrestrial polar habitats. These habitats include soils, permafrost, cryptic niches (including biological soil crusts, hypoliths and endoliths), ice and snow, and a range of aquatic habitats. Here we review current literature on the ecology, and the functional role played by cyanobacteria in various Arctic and Antarctic environments. We focus on the ecological importance of cyanobacterial communities in Polar Regions and assess what is known regarding the toxins they produce. We also review the responses and adaptations of cyanobacteria to extreme environments.

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“…However, studies on the role of this large bacterial community in biogeochemical cycles are necessary to determine which of these microorganisms are really active in this extreme environment. In a recent report, Hopkins et al (2009) described evidence of a contribution of microorganisms to organic carbon turnover in the soil in Antarctic dry valleys, which make up one of the most environmentally harsh terrestrial ecosystems. Such information is essential to help us predict the possible consequences of microbial disturbances and their consequent impacts on biogeochemical transformations in Antarctic ecosystems.…”

Section: Discussionmentioning

confidence: 99%

Bacterial diversity in rhizosphere soil from Antarctic vascular plants of Admiralty Bay, maritime Antarctica

et al. 2010

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The Antarctic is a pristine environment that contributes to the maintenance of the global climate equilibrium. The harsh conditions of this habitat are fundamental to selecting those organisms able to survive in such an extreme habitat and able to support the relatively simple ecosystems. The DNA of the microbial community associated with the rhizospheres of Deschampsia antarctica Desv (Poaceae) and Colobanthus quitensis (Kunth) BartI (Caryophyllaceae), the only two native vascular plants that are found in Antarctic ecosystems, was evaluated using a 16S rRNA multiplex 454 pyrosequencing approach. This analysis revealed similar patterns of bacterial diversity between the two plant species from different locations, arguing against the hypothesis that there would be differences between the rhizosphere communities of different plants. Furthermore, the phylum distribution presented a peculiar pattern, with a bacterial community structure different from those reported of many other soils. Firmicutes was the most abundant phylum in almost all the analyzed samples, and there were high levels of anaerobic representatives. Also, some phyla that are dominant in most temperate and tropical soils, such as Acidobacteria, were rarely found in the analyzed samples. Analyzing all the sample libraries together, the predominant genera found were Bifidobacterium (phylum Actinobacteria), Arcobacter (phylum Proteobacteria) and Faecalibacterium (phylum Firmicutes). To the best of our knowledge, this is the first major bacterial sequencing effort of this kind of soil, and it revealed more than expected diversity within these rhizospheres of both maritime Antarctica vascular plants in Admiralty Bay, King George Island, which is part of the South Shetlands archipelago.

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Isotopic evidence for the provenance and turnover of organic carbon by soil microorganisms in the Antarctic dry valleys

Cited by 64 publications

References 71 publications

Highly specialized microbial diversity in hyper-arid polar desert

Highly specialized microbial diversity in hyper-arid polar desert

Ecology and biogeochemistry of cyanobacteria in soils, permafrost, aquatic and cryptic polar habitats

Bacterial diversity in rhizosphere soil from Antarctic vascular plants of Admiralty Bay, maritime Antarctica

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