Aeolian transport of viable microbial life across the Atacama Desert, Chile: Implications for Mars

Azua‐Bustos, Armando; González-Silva, Carlos; Fernández-Martínez, Miguel Ángel; Arenas-Fajardo, Cristián; Fonseca, Ricardo; Martín-Torres, F. J.; Fernández-Sampedro, M.; Fairén, Alberto González; Zorzano, María Paz

doi:10.1038/s41598-019-47394-z

Cited by 40 publications

(33 citation statements)

References 55 publications

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“…Wide distributions of similar phage genomes were also observed in other environments (62)(63)(64). One specific mechanism of dispersal in the Atacama Desert may be frequent sandstorms and powerful winds (65,66) transporting infected microbes and viral entities in organic aerosols (67,68). This mode of dispersal is consistent with the higher counts of unique predicted viral genomes in the control soils (adjacent to boulders) compared to the soils below the boulders that remain stable for years except during occasional seismic activities (69).…”

Section: Viral Dispersal By Wind the Genetic Similarity Between Virumentioning

confidence: 67%

Diverse viruses carrying genes for microbial extremotolerance in the Atacama Desert hyperarid soil

Hwang

Rahlff

Schulze‐Makuch

et al. 2020

Preprint

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Viruses play an essential role in shaping microbial community structures and serve as reservoirs for genetic diversity in many ecosystems. In hyperarid desert environments, where life itself becomes scarce and loses diversity, the interactions between viruses and host populations have remained elusive. Here, we resolved host-virus interactions in the soil metagenomes of the Atacama Desert hyperarid core, one of the harshest terrestrial environments on Earth. We show dispersal of diverse and abundant viruses that infect a wide range of hosts over 205 km across the desert. Host genomes encoded both adaptive and innate immune systems, providing evidence of viral predation being a key selective pressure along with abiotic stresses. Viral genomes carried extremotolerance features (i.e. DNA repair proteins, enzymes against oxidative damage) and other auxiliary metabolic genes, indicating that viruses could mediate the spread of microbial resilience against environmental stress across the desert. Our results suggest that the host-virus interactions in the Atacama Desert soils are dynamic and complex, shaping uniquely adapted microbiomes in this highly selective and hostile environment.ImportanceDeserts are one of the largest and rapidly expanding terrestrial ecosystems characterized by low biodiversity and biomass. The hyperarid core of the Atacama Desert, previously thought to be devoid of life, is one of the harshest environments supporting only scant biomass of highly adapted microbes. While there is growing evidence that viruses play essential roles in shaping the diversity and structure of nearly every ecosystem, very little is known about the role of viruses in desert soils, especially where viral contact with viable hosts is significantly reduced. Our results indicate that viruses are abundant, diverse and widely dispersed across the desert, potentially spreading key stress resilience and metabolic genes to ensure host survival. The desertification accelerated by climate change expands both the ecosystem cover and the ecological significance of the desert virome. This study sheds light on the complex evolutionary dynamics that shape the unique and poorly understood host-virus relationships in desert soils.

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Section: Viral Dispersal By Wind the Genetic Similarity Between Virumentioning

confidence: 67%

Diverse viruses carrying genes for microbial extremotolerance in the Atacama Desert hyperarid soil

Hwang

Rahlff

Schulze‐Makuch

et al. 2020

Preprint

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“…The case of Bacillus spp. is worth mentioning, as species of this genus are among the first and one of the most common type of bacteria reported in Yungay 27,65,66 and also in other sites of the hyperarid core of the Atacama [67][68][69] .…”

Section: Resultsmentioning

confidence: 97%

“…6a,c). Because these are highly recalcitrant biomolecules, able to resist decay even for billions of years 83 , and considering that the samples were collected at 40 cm depth, their presence may be potentially explained by the aerial input of allochthonous material coming from elsewhere in the distant past 30,69,80 . The aerial transport of such recalcitrant biomolecules have been described in the Atacama in places such as the neighboring Salar Grande 80 and in other www.nature.com/scientificreports/ those inhabiting surface halites 40,56,71 .…”

Section: Resultsmentioning

confidence: 99%

Inhabited subsurface wet smectites in the hyperarid core of the Atacama Desert as an analog for the search for life on Mars

Azua‐Bustos

Fairén

González-Silva

et al. 2020

Sci Rep

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The modern Martian surface is unlikely to be habitable due to its extreme aridity among other environmental factors. This is the reason why the hyperarid core of the Atacama Desert has been studied as an analog for the habitability of Mars for more than 50 years. Here we report a layer enriched in smectites located just 30 cm below the surface of the hyperarid core of the Atacama. We discovered the clay-rich layer to be wet (a phenomenon never observed before in this region), keeping a high and constant relative humidity of 78% (aw 0.780), and completely isolated from the changing and extremely dry subaerial conditions characteristic of the Atacama. The smectite-rich layer is inhabited by at least 30 halophilic species of metabolically active bacteria and archaea, unveiling a previously unreported habitat for microbial life under the surface of the driest place on Earth. The discovery of a diverse microbial community in smectite-rich subsurface layers in the hyperarid core of the Atacama, and the collection of biosignatures we have identified within the clays, suggest that similar shallow clay deposits on Mars may contain biosignatures easily reachable by current rovers and landers.

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“…These taxa were particularly abundant in control samples and near absent in below boulder samples, suggesting specific and unknown selection processes for the two different sample types. Alternatively, some of these taxa may be deposited through aeolian transport (45). The lack of nitrogen fixation and denitrification genes suggest low overall biological input and little loss of biologically available nitrogen.…”

Section: Atacama Soils Below Boulders Harbor Unique Microbial Communimentioning

confidence: 99%

Leave no stone unturned: The hidden potential of carbon and nitrogen cycling by novel, highly adapted Thaumarchaeota in the Atacama Desert hyperarid core

Hwang

Schulze‐Makuch

Arens

et al. 2020

Preprint

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The hyperarid core of the Atacama Desert is an extremely harsh environment previously thought to be colonized by only a few heterotrophic bacterial species. In addition, carbon and nitrogen cycling in these highly oligotrophic ecosystems are poorly understood. Here we genomically resolved a novel genus of Thaumarchaeota, Ca. Nitrosodesertus, found below boulders of the Atacama hyperarid core, and used comparative genomics to analyze their pangenome and site-specific adaptations. Their genomes contain genes for ammonia oxidation and the 3-hydroxypropionate/4-hydroxybutyrate carbon fixation pathway, indicating a chemolithoautotrophic lifestyle. Ca. Nitrosodesertus possesses the capacity for tolerating extensive environmental stress highlighted by the presence of genes against oxidative stress, DNA damage and genes for the formation of biofilms. These features are likely responsible for their dominance in samples with extremely low water content across three different boulder fields and eight different boulders. Genome-specific adaptations of the genomes included the presence of additional genes for UV resistance, heavy metal transporters, multiple types of ATP synthases, and divergent genes for aquaporins. Our results suggest that Thaumarchaeota mediate important carbon and nitrogen cycling in the hyperarid core of the Atacama and are part of its continuous and indigenous microbiome.

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Aeolian transport of viable microbial life across the Atacama Desert, Chile: Implications for Mars

Cited by 40 publications

References 55 publications

Diverse viruses carrying genes for microbial extremotolerance in the Atacama Desert hyperarid soil

Diverse viruses carrying genes for microbial extremotolerance in the Atacama Desert hyperarid soil

Inhabited subsurface wet smectites in the hyperarid core of the Atacama Desert as an analog for the search for life on Mars

Leave no stone unturned: The hidden potential of carbon and nitrogen cycling by novel, highly adapted Thaumarchaeota in the Atacama Desert hyperarid core

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