Carbon, nitrogen and temperature controls on microbial activity in soils from an Antarctic dry valley

Hopkins, D. W.; Sparrow, Ashley D.; Elberling, Bo; Gregorich, E.G.; Novis, Phil M.; Greenfield, L. G.; Tilston, Emma L.

doi:10.1016/j.soilbio.2006.01.012

Cited by 118 publications

(95 citation statements)

References 35 publications

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“…The C/N ratio indicates much lower values in our study sites (ranging between 0.3 and 7.4) with respect to the Dry Valleys (ranging between 9.2 and 87.8) (Hopkins et al, 2006). The lower C/N ratio and the higher water content of our soils show that, along the investigated transect, the decomposition processes of the organic matter seem to be more active than in the Dry Valleys and not so limited by soil moisture, although further analyses are still required to measure the decomposition rates at Victoria Land.…”

Section: Discussioncontrasting

confidence: 64%

Biotic and abiotic factors influencing soil properties across a latitudinal gradient in Victoria Land, Antarctica

et al. 2008

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Section: Discussioncontrasting

confidence: 64%

Biotic and abiotic factors influencing soil properties across a latitudinal gradient in Victoria Land, Antarctica

et al. 2008

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“…Of interest was the observation of pathways for transformation of lignin-like, complex organic aromatic substrates, because these are among the more recalcitrant of soil substrates (4,60) and can be envisaged to be widely available in mineral soils with low turnover and exogenous input. That these were common to soils but not to rocky niches offers further evidence that they have been selected for on this basis, because rocky niches are not reservoirs for the "legacy" carbon that is known to endure in Antarctic soils (4).…”

Section: Discussionmentioning

confidence: 99%

Functional ecology of an Antarctic Dry Valley

Chan

Nostrand

Zhou

et al. 2013

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

178

173

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The McMurdo Dry Valleys are the largest ice-free region in Antarctica and are critically at risk from climate change. The terrestrial landscape is dominated by oligotrophic mineral soils and extensive exposed rocky surfaces where biota are largely restricted to microbial communities, although their ability to perform the majority of geobiological processes has remained largely uncharacterized. Here, we identified functional traits that drive microbial survival and community assembly, using a metagenomic approach with GeoChip-based functional gene arrays to establish metabolic capabilities in communities inhabiting soil and rock surface niches in McKelvey Valley. Major pathways in primary metabolism were identified, indicating significant plasticity in autotrophic, heterotrophic, and diazotrophic strategies supporting microbial communities. This represents a major advance beyond biodiversity surveys in that we have now identified how putative functional ecology drives microbial community assembly. Significant differences were apparent between open soil, hypolithic, chasmoendolithic, and cryptoendolithic communities. A suite of previously unappreciated Antarctic microbial stress response pathways, thermal, osmotic, and nutrient limitation responses were identified and related to environmental stressors, offering tangible clues to the mechanisms behind the enduring success of microorganisms in this seemingly inhospitable terrain. Rocky substrates exposed to larger fluctuations in environmental stress supported greater functional diversity in stress-response pathways than soils. Soils comprised a unique reservoir of genes involved in transformation of organic hydrocarbons and lignin-like degradative pathways. This has major implications for the evolutionary origin of the organisms, turnover of recalcitrant substrates in Antarctic soils, and predicting future responses to anthropogenic pollution.

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“…This biomass accumulates at the edges of these water bodies where it is freeze-dried and can be blown throughout the valley distributing organisms and providing carbon and nitrogen subsidies to areas of low productivity (Parker et al 1982;Elberling and Brandt 2003;Moorhead et al 2003;Nkem et al 2006;Hopkins et al 2006a;Barrett et al 2006b;Wood et al 2008). The size of these aquatic systems, along with wind intensity and direction, influence the relative contribution of these sources to valley-wide nutrient cycling and productivity (Hopkins et al 2006a, b). While there is evidence of increased organic carbon with increased proximity to lakes (Elberling and Brandt 2003), ponds (Moorhead et al 2003), and streams ), similar bacterial and metazoan taxa across geographic latitudes indicate this mat material is also widely dispersed (Barrett et al 2006a).…”

Section: Desert Soilsmentioning

confidence: 99%

“…Stable isotope signatures indicate that carbon and nitrogen in contemporary lake sediments provide the bulk of organic matter to the valleys especially for the contiguous low-elevation areas (Barrett et al 2006b). Additionally, 'legacy carbon' from ancient lake mats may be an important source of organic matter to soils lacking contemporary primary productivity (Burkins et al 2000(Burkins et al , 2001Hopkins et al 2006a).…”

Section: Desert Soilsmentioning

confidence: 99%