Desert Environments: Soil Microbial Communities in Hot Deserts

Kieft, Thomas L.

doi:10.1002/0471263397.env178

Cited by 9 publications

(7 citation statements)

References 124 publications

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“…For example, there is some evidence that environments in which overall microbial abundance is lower have more spatially- and temporally diverse communities ( e.g. , Banerjee et al , 2011 and references reviewed in Kieft, 2003 ).…”

Section: Introductionmentioning

confidence: 99%

Correlations Between Life-Detection Techniques and Implications for Sampling Site Selection in Planetary Analog Missions

et al. 2017

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We conducted an analog sampling expedition under simulated mission constraints to areas dominated by basaltic tephra of the Eldfell and Fimmvörðuháls lava fields (Iceland). Sites were selected to be “homogeneous” at a coarse remote sensing resolution (10–100 m) in apparent color, morphology, moisture, and grain size, with best-effort realism in numbers of locations and replicates. Three different biomarker assays (counting of nucleic-acid-stained cells via fluorescent microscopy, a luciferin/luciferase assay for adenosine triphosphate, and quantitative polymerase chain reaction (qPCR) to detect DNA associated with bacteria, archaea, and fungi) were characterized at four nested spatial scales (1 m, 10 m, 100 m, and >1 km) by using five common metrics for sample site representativeness (sample mean variance, group F tests, pairwise t tests, and the distribution-free rank sum H and u tests). Correlations between all assays were characterized with Spearman's rank test. The bioluminescence assay showed the most variance across the sites, followed by qPCR for bacterial and archaeal DNA; these results could not be considered representative at the finest resolution tested (1 m). Cell concentration and fungal DNA also had significant local variation, but they were homogeneous over scales of >1 km. These results show that the selection of life detection assays and the number, distribution, and location of sampling sites in a low biomass environment with limited a priori characterization can yield both contrasting and complementary results, and that their interdependence must be given due consideration to maximize science return in future biomarker sampling expeditions. Key Words: Astrobiology—Biodiversity—Microbiology—Iceland—Planetary exploration—Mars mission simulation—Biomarker. Astrobiology 17, 1009–1021.

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Section: Introductionmentioning

confidence: 99%

Correlations Between Life-Detection Techniques and Implications for Sampling Site Selection in Planetary Analog Missions

et al. 2017

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“…Therefore, the correlations between the bacterial community and C and N parameters may be location‐specific, and the bacterial community may not be the main driver of the organic C and N cycle under native Caatinga vegetation and grazing exclusion. However, members of the fungal community are more tolerant to dry conditions than bacteria (Kieft, 2003), and it highlights the importance of further studies regarding fungal communities in the Caatinga biome and their relationships with soil functions, especially mycorrhizal fungi (Guo et al, 2016; Macdonald et al, 2015). In addition, by studying both bacteria and fungi, Xun et al (2018) demonstrated that the relationships between the activity of C‐decomposing enzymes and microbial abundance are more important for the fungi community, especially in C‐recalcitrant turnover, while bacteria are more important in labile‐C turnover.…”

Section: Discussionmentioning

confidence: 99%

Grazing exclusion regulates bacterial community in highly degraded semiarid soils from the Brazilian Caatinga biome

et al. 2021

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Grazing exclusion has been applied as a suitable strategy for soil conservation worldwide, mainly on semiarid soils. However, it is unclear how grazing exclusion reduces the negative effects of overgrazing on the microbial community in the Caatinga biome. In our study, we assessed the bacterial community under three different soil managements in a semiarid region of the Brazilian Caatinga biome, as follows: (a) Native Caatinga vegetation (natural); (b) grazing exclusion (exclusion); and(c) overgrazing (grazed). The bacterial community was assessed through the sequencing of the V4 region of the 16S rRNA gene and analyzed soil chemical and physical properties were correlated with the bacterial community structure. Our results demonstrate that exclusion increases the content of soil carbon and nitrogen, and bacterial diversity, while grazed showed a reduction of 31 and 43% in organic C, compared to exclusion and natural, respectively. However, the changes in bacterial diversity were more expressive in a specific site (No. 1), suggesting that exclusion strategy could be a context-dependent and complex approach to protecting or improving Caatinga soils. Moreover, grazed areas might restrain the potential of bacterial diversity to sustain ecosystem functions since nonbeneficial elements increased in grazed treatments, which presented a negative correlation with the bacterial community. Our study provides novel evidence that high-intensity disturbance by overgrazing could not only reduce soil fertility but it may also restrain bacterial composition, with implications on ecosystem functioning. The Caatinga soil microbiome may be unable to maintain ecosystem services such as plant and animals' development under overgrazing management.

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“…Such acidophilic archaea are among the oldest organisms on Earth (Woese, 1998). Similarly, >75% sulfuric acid corresponds to a very low water activity (a w ) of <0.02 (Gentry and Dahlgren, 2019), substantially below that of even the most saturated brines (Bolhuis et al, 2006) and at best on par with Earth's driest deserts (Kieft, 2003). Sulfuric acid abundances in Venus' aerosols are not based on direct measurements but rather from the index of refraction deduced from polarization data (Hansen and Hovenier, 1974;Rossi et al, 2015), and optical glory feature data (Markiewicz et al, 2014), along with computational simulations (Krasnopolsky, 2015) and compatible with vapor abundances determined from radio occultation profiles (Steffes and Eshleman, 1982).…”

Section: Potential For a Habitable Zone For Polyextremophiles In Venus' Cloudsmentioning

confidence: 99%

Venus, an Astrobiology Target

et al. 2021

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We present a case for the exploration of Venus as an astrobiology target-(1) investigations focused on the likelihood that liquid water existed on the surface in the past, leading to the potential for the origin and evolution of life, (2) investigations into the potential for habitable zones within Venus' present-day clouds and Venus-like exo atmospheres, (3) theoretical investigations into how active aerobiology may impact the radiative energy balance of Venus' clouds and Venus-like atmospheres, and (4) application of these investigative approaches toward better understanding the atmospheric dynamics and habitability of exoplanets. The proximity of Venus to Earth, guidance for exoplanet habitability investigations, and access to the potential cloud habitable layer and surface for prolonged in situ extended measurements together make the planet a very attractive target for near term astrobiological exploration.

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Desert Environments: Soil Microbial Communities in Hot Deserts

Abstract: Soil Water Potential Desert Soil Microbial Abundance Spatial and Temporal Distributions Diversity of Desert Soil Microbes Adaptations to Desert Soil Conditions Practical Applications

Cited by 9 publications

References 124 publications

Correlations Between Life-Detection Techniques and Implications for Sampling Site Selection in Planetary Analog Missions

Correlations Between Life-Detection Techniques and Implications for Sampling Site Selection in Planetary Analog Missions

Grazing exclusion regulates bacterial community in highly degraded semiarid soils from the Brazilian Caatinga biome

Venus, an Astrobiology Target

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