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Bennett’s chinchilla rat (Abrocoma bennettii) is an hystricomorph rodent endemic to Chile inhabiting semi-arid and meditarranean regions below 2,000 m above sea level, from northern and central Chile. Using various lines of evidence, including camera traps, skulls, middens, and DNA, this study reports two new records of A. bennettii discovered during the course of a baseline fauna survey. These new records expand their current altitudinal limit up to 3,500 m above sea level and reveal an unprecedented potential sympatry with Abrocoma cinerea in the Andes of the Atacama Region, highlighting the ecological versatility of this common yet elusive rodent. [ABSTRACT FROM AUTHOR]

The region of Arica and Parinacota hosts unexplored remote sites with unique characteristics suitable for developing novel agricultural bioproducts. Notable locations include Jurasi Hot Springs, Polloquere Hot Springs, and Amuyo Lagoons, featuring open pools fed by thermal mountain springs. These geothermal sites harbor bacteria with plant growth-promoting activities, particularly interesting to the strains J19, TP22, A20, and A3. These bacteria possess in vitro plant growth-promoting traits, the ability to produce hydrolytic enzymes, and the capacity to inhibit phytopathogenic fungi. Moreover, they can tolerate different concentrations of NaCl and boron, making them suitable for developing new agricultural bioproducts for arid environments. The bacterial strains A3 and A20 have a positive effect on the growth of the aerial part of tomato plants (increased stem length, fresh and dry weight), with a significant increment in proline concentration and chlorophyll A and B content under saline conditions. Meanwhile, the strains J19 and TP22 exhibit herbicidal activity against Cenchrus echinatus by reducing root elongation and germination of the weed. These strains possess plant growth-promoting traits and improve plant resistance to salinity stress. They are promising candidates for developing innovative bio-based agricultural products suited to arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Organisms in adaptive radiations are able to diversify and colonize multiple environments. Frequently, the evolution of key adaptations enables organisms to confront novel environmental challenges, promoting diversification. Here, we studied desert colonization in the Liolaemus radiation. We assessed the patterns of climatic niche evolution in the L. nigromaculatus section, one Liolaemus clade inhabiting the Atacama Desert. We found that evolution toward arid conditions occurred in two clades independently: one clade colonized the desert through warm coastal environments, and the other through cold highland environments on the Andes Mountains. The precipitation climatic niche evolved fast and early during this clade's evolutionary history, following an early burst (EB) model of evolution, whereas the thermal climatic niche evolved under Brownian motion (BM) and at a lower rate. Additionally, we explored some features that could have facilitated desert colonization: a higher chromosome number was associated with warmer temperatures, lower selected body temperatures were associated with higher environmental temperatures and drier climates, larger and more elongated bodies with colder environments, and longer limbs and tails were associated with higher thermal variation. Our results highlight that organisms can confront challenging environments in multiple ways such that some niche axes may evolve faster during the colonization of novel environments, and that radiated groups may have the evolutionary potential to rapidly evolve these adaptations. [ABSTRACT FROM AUTHOR]

The Atacama Desert in Chile is one of the driest and most inhospitable places on Earth. To analyze the diversity and distribution of microbial communities in such an environment, one of the most important and challenging steps is DNA extraction. Using commercial environmental DNA extraction protocols, a mixture of living, dormant, and dead cells of microorganisms is extracted, but separation of the different DNA pools is almost impossible. To overcome this problem, we applied a novel method on soils across a west-east moisture transect in the Atacama Desert to distinguish between extracellular DNA (eDNA) and intracellular DNA (iDNA) at the cell extraction level. Here, we show that a large number of living and potentially active microorganisms, such as Acidimicrobiia, Geodermatophilaceae, Frankiales, and Burkholderiaceae, occur in the hyperarid areas. We observed viable microorganisms involved as pioneers in initial soil formation processes, such as carbon and nitrogen fixation, as well as mineral-weathering processes. In response to various environmental stressors, microbes coexist as generalists or specialists in the desert soil environment. Our results show that specialists compete in a limited range of niches, while generalists tolerate a wider range of environmental conditions. Use of the DNA separation approach can provide new insights into different roles within viable microbial communities, especially in low-biomass environments where RNA-based analyses often fail. [ABSTRACT FROM AUTHOR]

The New World micromoth genus Keiferia Busck, 1939 (Lepidoptera, Gelechiidae, Gelechiinae, Gnorimoschemini) includes 21 described species, ten of which occur in South America. Like the tomato pinworm, K. lycopersicella (Walsingham, 1897), all the species of Keiferia, whose host plants have been documented, are associated exclusively with members of the family Solanaceae.Keiferia azapaensis sp. nov. is described and illustrated, based on adults reared from leaf miner larvae collected on the shrub Trixis cacalioides (Kunth) D. Don (Asteraceae) in the Atacama Desert, northern Chile. Despite this unusual host plant, a Maximum Likelihood analysis, based on mitochondrial DNA sequences, placed the new species within a well-supported Keiferia clade. The discovery of the trophic association between K. azapaensis sp. nov. and T. cacalioides represents the first record of a member of Asteraceae as a host plant for the micromoth genus Keiferia.

According to current literature, Galictis cuja (Molina, 1782) does not inhabit the desert of Chile. However, a previous ecological niche analysis had indicated a high probability of the mustelid Quique’s occurrence in the ravines that cross the northern desert of Chile. We present the first finding of Galictis cuja in the northern desert of Tarapaca region, Chile, apparently attacked and killed by dogs, which indicates an expansion of its distribution range and the utilization of microhabitats.

This article discusses the archaeological implications of the discovery of the highland species Hippocamelus antisensis (Cervidae) and Vicugna vicugna (Camelidae) in two coastal contexts in the Atacama Desert (20°S, Chile). H. antisensis is currently distributed throughout the Peruvian Andes, northern Chile, western Bolivia and northwestern Argentina, between 1800 and 5500 m above sea level. V. vicugna is distributed throughout northern Peru and northwestern Argentina, in environments that exceed 3200 m above sea level. The archaeological record of deer antlers on the Atacama coast has previously been documented at the Caleta Huelén‐42 site (21°S). In the case of V. vicugna, fibers have been recovered only at the coastal site of Camarones‐14 (19°S). A dating of 4180 ± 20 year BP obtained from V. vicugna bone and indirect dating of the antlers suggest an early social exchange between groups from coastal regions and those from the Atacama Desert Mountain range, as well as encourage to the potential record of remains/products of these animals in areas far from their natural habitats. [ABSTRACT FROM AUTHOR]

Drought stress is a key limitation for plant growth and colonization of arid habitats. We study the evolution of gene expression response to drought stress in a wild tomato, Solanum chilense, naturally occurring in dry habitats in South America. We conduct a transcriptome analysis under standard and drought experimental conditions to identify drought‐responsive gene networks and estimate the age of the involved genes. We identify two main regulatory networks corresponding to two typical drought‐responsive strategies: cell cycle and fundamental metabolic processes. The metabolic network exhibits a more recent evolutionary origin and a more variable transcriptome response than the cell cycle network (with ancestral origin and higher conservation of the transcriptional response). We also integrate population genomics analyses to reveal positive selection signals acting at the genes of both networks, revealing that genes exhibiting selective sweeps of older age also exhibit greater connectivity in the networks. These findings suggest that adaptive changes first occur at core genes of drought response networks, driving significant network re‐wiring, which likely underpins species divergence and further spread into drier habitats. Combining transcriptomics and population genomics approaches, we decipher the timing of gene network evolution for drought stress response in arid habitats. [ABSTRACT FROM AUTHOR]

The Amuyo Ponds (APs) are a group of three brackish hydrothermal lagoons located at 3700 m above sea level in a pre-Andean setting in the Atacama Desert. Each pond shows a conspicuous green (GP), red (RP), or yellow (YP) coloration, and discharges water rich in arsenic and boron into the Caritaya River (Camarones Basin, northern Chile). Microorganisms are subjected to harsh environmental conditions in these ponds, and the microbial composition and diversity in the Amuyo Ponds' sediments are unknown. The microbial life colonizing AP sediments was explored by metagenomics analyses, showing a diverse microbial life dominated by members of the bacterial domain, with nearly 800 bacterial genome sequences, and sequences associated with Archaea, Eukarya, and viruses. The genus Pseudomonas was more abundant in GP and YP sediments, while the genera Pseudomonas, Aeromonas, and Shewanella were enriched in RP sediments. Archaeal composition was similar in all sediments, and enriched with methanogens sequences from the Archaeoglobi and Halobacteria classes. Abundant fungi sequences were detected in all sediments from the phyla Blastocladiomycota and Ascomycota. We also report putative functional capabilities related to virulence and defense genes, the biosynthesis of secondary metabolites, and tolerance to arsenic. Thirteen bacterial and fourteen viral metagenome-assembled genomes were reconstructed and informed here. This work expands our knowledge on the richness of the microorganisms in the APs and open further studies on the ecology and genomics of this striking Andean geosite. [ABSTRACT FROM AUTHOR]

The Andean uplift and the concomitant aridification drove the rapid diversification of several plant lineages that were able to colonize warmer and drier habitats at low elevations and wetter and colder habitats at high elevations. These transitions may be facilitated by shifts in plant strategies to cope with drought and cold, which in turn can trigger episodes of accelerated species diversification. Here, we used four nuclear DNA markers to infer phylogenetic relationships of 80 Adesmia species of annuals, perennial herbs, shrubs and small shrubs that occur in Chile and Argentina. We reconstructed ancestral states for area, climatic niche and growth form to explore how Andean uplift and aridification promoted Adesmia diversification. We also performed logistic and linear regression analyses between different components of growth form (life span, woodiness and plant height) and climate. Finally, we estimated speciation rates across the phylogeny. Our results suggest that the ancestor of Chilean Adesmia was a perennial herb that probably originated in the high Andes of northern and central Chile. The low elevations of Central Chile were colonized in the late Miocene, whereas the high latitudes of Patagonia and the hyperarid coastal Atacama Desert were colonized repeatedly since Pliocene by lineages with different growth forms. Multiple and bidirectional transitions between annual and perennial habits and between herbaceous and woody habits were detected. These shifts were not correlated with climate, suggesting that the different growth forms are alternative and successful strategies to survive unfavorable seasons of both desert and high Andes. Net diversification analysis indicated a constant rate of diversification, suggesting that the high species diversity of Adesmia that occur in Chile is due to a uniform speciation process rather than to accelerated episodes of speciation. [ABSTRACT FROM AUTHOR]

The Atacama Desert's naturally elevated metal(loid)s pose a unique challenge for assessing the environmental impact of mining, particularly for indigenous communities residing in these areas. This study investigates how copper mining influences the dispersion of these elements in the wind‐transportable fraction (<75 μm) of surface sediments across an 80 km radius. We employed a multi‐pronged approach, utilizing spatial modeling to map element distributions, exponential decay analysis to quantify concentration decline with distance, regime shift modeling to identify dispersion pattern variations, and pollution assessment to evaluate impact. Our results reveal significant mining‐driven increases in surface concentrations of copper (Cu), molybdenum (Mo), and arsenic (As). Notably, within the first 20 km, concentrations peaked at 1,016 mg kg⁻1 for Cu, 31 mg kg⁻1 for Mo, and a remarkable 165 mg kg⁻1 for As. Cu and Mo displayed significant dispersion, extending up to 50 km from the source. However, As exhibited the most extensive reach, traveling up to 70 km downwind, highlighting the far‐reaching ecological footprint of mining operations. Mineralogical analyses corroborated these findings, identifying mining‐related minerals in surface sediments far beyond the immediate mining area. Although pollution indices based on the proposed Local Geochemical Background reveal significant contamination across the study area, establishing accurate pre‐industrial baseline values is essential for a more reliable assessment. This study challenges the concept of "natural pollution" by demonstrating that human activities exacerbate baseline metal(loid)s levels. Expanding monitoring protocols is imperative to comprehensively assess the combined effects of multiple emission sources, including mining and natural processes, in safeguarding environmental and human health for future generations. Plain Language Summary: The Atacama Desert, already notorious for its hyper‐arid conditions, faces an added challenge: high natural metal levels are amplified by mining emissions. This raises environmental justice concerns, especially for nearby communities, including indigenous populations. By analyzing sediment chemistry and applying spatial mapping, we tracked how mining disperses contaminated dust across a vast 80‐km radius. Our findings overturn the assumption that desert pollution stems solely from natural causes. Mining significantly boosts copper, molybdenum, and arsenic in surface sediment. The situation is most alarming within the first 20 km downwind, where arsenic, known for its toxicity, can reach over 11 times natural estimates. Furthermore, arsenic‐laced dust travels up to 70 km away, highlighting the far‐reaching environmental impact of mining. The presence of mining‐related minerals in the sediment confirms the spread of metal through dust dispersion. While our study reveals significant contamination, pinpointing the exact extent requires more precise data on natural metal levels. In conclusion, this research emphasizes how mining can worsen pollution in already metal‐rich environments, disproportionately impacting nearby communities. It underscores the importance of environmental justice. We recommend expanding environmental monitoring to encompass all pollution sources, both mining and natural processes, to safeguard humans and the environment for future generations. Key Points: Atacama mining disturbs natural metal patterns, elevating surface levels of copper, molybdenum, and arsenicMining dust spreads 70+ km in Atacama, posing health risks to nearby communitiesThe study refutes the notion that arsenic in Atacama is only due to natural processes [ABSTRACT FROM AUTHOR]

This study was designed to recover representative culturable actinomycetes from the Atacama Desert, and to detect their ability to promote plant growth under drought conditions. Environmental samples were taken from three Atacama Desert habitats, namely, from the Aguas Calientes, Lomas Bayas and Yungay core regions. With one exception higher actinomycete counts were obtained when isolation media were inoculated with mineral particles than with corresponding aliquots of serial dilution. Comparative 16S rRNA gene sequencing showed that representative isolates belonged to thirteen genera including putative novel Blastococcus, Kocuria, Micromonospora, Pseudonocardia, Rhodococcus and Streptomyces species. Representative isolates produced indole-3-acetic acid, siderophore and solubilized phosphate as well as displaying an ability to grow under drought conditions. In conclusion, the current findings open up exciting prospects for the promising potential of actinomycetes from the Atacama Desert to be used as bioinoculants to promote plant growth in arid and semi-arid biomes. [ABSTRACT FROM AUTHOR]

In this article, we ask how traces of political violence in the Atacama Desert and in the Sonoran Desert are created and how they are (or are not) transformed into archives. The political violence we study is of different types and takes place in different periods: state violence under the civil–military dictatorship (1973-1990) in the Atacama; violence as a product of migratory policies (from 1994 to the present) of the US–Mexican border in the Sonoran Desert in Arizona; and, mass death and disappearance as the product of successive governments' "war on drugs" (from 2006 to the present) in Sonora, Mexico. This article is based on our academic ethnographic work and volunteering with grassroots organizations. In these three arid spaces, we met different groups: family members and activists searching for political prisoners disappeared in the 1970s by the Pinochet regime; activists searching for migrants, dead or alive, lost in the Sonoran Desert in Arizona; and families digging in the earth, unearthing clandestine graves and hoping one day to find the remains of their loved ones. We argue that these different search practices create traces when these groups uncover what the perpetrators wanted to hide. These processes that create traces, then create archives when the situated and lived experience of searching and tracing is translated into artifacts that can be detached from their context and acquire multiple uses outside their place of production. [ABSTRACT FROM AUTHOR]

Chile is a biodiversity hotspot for Loasaceae. Although relatively well known (especially compared to countries further north along the tropical Andes), it is expected that the number of taxa in Chile is bound to change due to taxonomic work on currently recognized taxa, new records for the country, and undescribed diversity. Loasa rotundifolia is endemic to the Atacama Desert and was described in 1893, however it has mostly been overlooked by recent national and regional Floristic catalogues that include Chile. It is a rare species known previously from only three herbarium collections worldwide. The main objective of this contribution is to provide a modern revision for this rare taxon, including an amended description, a description of its distributional range, ecological notes, and a preliminary assessment of its conservation status. We studied material in SGO and CONC, mapped the distribution of the species, and assessed its preliminary conservation status in GeoCAT. We found that Loasa rotundifolia is a distinct species due to its unique leaf morphology and habitat preferences. Our revision indicates that the species is phylogenetically part of Loasa ser. Macrospermae, endemic to Región de Atacama and we recommend it to be regarded as Endangered, according both to our GeoCAT analyses and the application of IUCN criteria.

This article explores how Francisco de Aguirre used the Copiapó Valley encomienda to negotiate political power during the transition from conquest to colonial rule in northern Chile. Simultaneously, we analyze the circumstances of how a native society was incorporated into the Spanish Empire after a decade of fighting and resistance on the fringes of the empire. The strategic use of the fear of native rebellions to close the road from Peru to Chile gave Aguirre enough power to negotiate an important political position, which in the future would clash with the colonial authorities. Copiapó Valley’s peripheral location in the southernmost Atacama Desert constituted a political gray zone for the colonial administration. This space contributed to consolidating power for Aguirre and enabled locals some negotiation power within the possibilities afforded by the colonial system.

We surveyed the presence of perchlorate-reducing microorganisms in available metagenomic data of halite environments from the Atacama Desert, an extreme environment characterized by high perchlorate concentrations, intense ultraviolet radiation, saline and oxidizing soils, and severe desiccation. While the presence of perchlorate might suggest a broad community of perchlorate reducers or a high abundance of a dominant taxa, our search reveals a scarce presence. In fact, we identified only one halophilic species, Salinibacter sp003022435, carrying the pcrA and pcrC genes, represented in low abundance. Moreover, we also discovered some napA genes and organisms carrying the nitrate reductase nasB gene, which hints at the possibility of cryptic perchlorate reduction occurring in these ecosystems. Our findings contribute with the knowledge of perchlorate reduction metabolism potentially occurring in halites from Atacama Desert and point towards promising future research into the perchlorate-reducing mechanism in Salinibacter, a common halophilic bacterium found in hypersaline ecosystems, whose metabolic potential remains largely unknown. [ABSTRACT FROM AUTHOR]

Studies performed in North America, Africa, and South America have led to the isolation of four new species of Kastovskya, a filamentous cyanobacterial genus that before this manuscript had only one species, Kastovskya adunca from Chile. Kastovskya nitens and K. viridissima were isolated from soils on San Nicolas Island, K. sahariensis was isolated from hypolithic habitats from the Sahara Desert in Algeria, and K. circularithylacoides was isolated from hypolithic habitats in Chile. The molecular analyses are corroborated by morphological data, morphometric analysis, and ecological and biogeographical considerations for robust polyphasic descriptions of all taxa. The peculiar transatlantic distribution of this genus bears similarity to other taxa in recently published studies and is in agreement with a hypothesis suggesting that cyanobacteria in Africa may disperse to the Americas on dust particles during windstorms. This work is unusual in that species in a single rare cyanobacterial genus with a disjunct distribution are described simultaneously from three continents. The 16S rRNA gene analyses performed for this study also revealed that another recent genus, Arizonema, is clearly a later synonym of Symplocastrum. This issue is resolved here with the collapsing of the type species Arizonema commune into Symplocastrum flechtnerae. [ABSTRACT FROM AUTHOR]

Since the nineteenth century, the Atacama Desert in Northern Chile has been a space of geopolitical tension, asymmetrical socioeconomic power, and a territory for mining extractivism. The knowledge of its natural and cultural resources was assembled by scientific expeditions defining and configuring what we understand as a 'desert,' a peripheral empty and arid space ready to be occupied and exploited. The irruption and expansion of capitalist extractivism created a particular idea of landscape and reconfigured its socio-political contours. Archaeological, scientific, and artistic expeditions actively participated in this 'becoming desert' process. This article examines some trajectories constituting the Atacama Desert as an extractive and sacrificial territory. We propose the notion of 'surrealistic landscapes,' and we use the poetry of the Chilean Canadian poet Ludwig Zeller to highlight the surreal condition of contemporary materialities, constantly feeding the archaeological imagination of Atacama. [ABSTRACT FROM AUTHOR]

Among mammals, bats harbour the greatest taxonomic diversity of ectoparasitic arthropods. This is mainly due to their high mobility, wide distribution range and gregarious social behaviour. In Chile, 17 species of bats have been reported; however, their ectoparasitic arthropofauna has been little studied. There are currently 12 taxa recorded, belonging to two classes and associated with only four species of bats. This study aimed to investigate the diversity of parasitic flies associated with bats in three ecoregions: Atacama Desert, Chilean Matorral and Valdivian temperate forest. During 2021, using mist nets, bats were captured in Anzota caves (Atacama Desert ecoregion), Huelquén and Alto Jahuel (Chilean Matorral ecoregion), Cherquenco and San Patricio (Valdivian temperate forest). Each bat was carefully checked during a 15‐min interval for the collection of ectoparasites. The arthropods were deposited in vials with 96% ethanol. A total of 26 bats corresponding to three species (Vespertilionidae: Histiotus magellanicus Philippi, 1866, Myotis arescens (Osgood, 1943); Phyllostomidae: Desmodus rotundus (Geoffroy, 1810)) were captured from which a total of 142 ectoparasitic arthropods were collected. Bat flies were separated/identified under a stereomicroscope. Additionally, from the fieldwork, we report the presence of other ectoparasites associated with Chilean bats. In our study, we report new host–parasite associations between Trichobius parasiticus Gervais, 1844 (Diptera: Streblidae) on D. rotundus, and Basilia silvae (Brèthes, 1913) (Diptera: Nycteribiidae) in M. arescens in Chile. Our study extended the latitudinal range of distribution for B. silvae to Araucanía region, and we report for first time T. parasiticus in the country. Additionally, partial sequences of the cytochrome c oxidase I gene were obtained from these specimens. Although there is slight morphological variation in the specimens of T. parasiticus, phylogenetic analyses suggest that they correspond to the same species. The sequences generated for B. silvae represent the first for the species. Authors recommend the use of an integrative approach in the identification of ectoparasites in poorly studied ecoregions and hosts. The integration of different markers is necessary to determine more precisely the phylogenetic relationships between South American populations and species of the genera Basilia and Trichobius. [ABSTRACT FROM AUTHOR]

The rapid growth of cities worldwide is a phenomenon that has generated numerous debates about the effects it could have on the environment and society. An issue that has not been well addressed in the literature is the relationship between expected urban growth and risks to natural hazards. The relationship is an important aspect for planning because urban expansion is uncertain. In this sense, land change simulation models can be useful tools to address this uncertainty, because simulation models can produce growth scenarios, which allow anticipation of exposure to natural threats. This article compares two land change simulation models: the CA_Markov model in the Selva version of IDRISI and the DINAMICA EGO model. We apply both models to extrapolate areas of future urban gain in the coastal cities of Antofagasta and Mejillones, where there is high exposure to tsunamis, mudslides, and steep slopes. The models can extrapolate differently in terms of both quantity and spatial allocation of urban gain depending on the parameter settings. CA_Markov projected urban growth adjacent to existing urban patches, while best fits to Markov equation, and the urban form was achieved with DINAMICA EGO, according to our parameter settings. We conclude that if modelers understand the models' behaviors, then applying these spatially explicit models to natural risks opens great prospects for urban planning and risk management, especially in countries highly exposed to dangerous natural events, such as in the case of Chile. [ABSTRACT FROM AUTHOR]

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The best ideotypes are under mounting pressure due to increased aridity. Understanding the conserved molecular mechanisms that evolve in wild plants adapted to harsh environments is crucial in developing new strategies for agriculture. Yet our knowledge of such mechanisms in wild species is scant. We performed metabolic pathway reconstruction using transcriptome information from 32 Atacama and phylogenetically related species that do not live in Atacama (sister species). We analyzed reaction enrichment to understand the commonalities and differences of Atacama plants. To gain insights into the mechanisms that ensure survival, we compared expressed gene isoform numbers and gene expression patterns between the annotated biochemical reactions from 32 Atacama and sister species. We found biochemical convergences characterized by reactions enriched in at least 50% of the Atacama species, pointing to potential advantages against drought and nitrogen starvation, for instance. These findings suggest that the adaptation in the Atacama Desert may result in part from shared genetic legacies governing the expression of key metabolic pathways to face harsh conditions. Enriched reactions corresponded to ubiquitous compounds common to extreme and agronomic species and were congruent with our previous metabolomic analyses. Convergent adaptive traits offer promising candidates for improving abiotic stress resilience in crop species. [ABSTRACT FROM AUTHOR]

Unique worldwide, nitrate/iodine deposits (NIDs) are located along a 700 km geological belt in the Atacama Desert, Chile. They serve as the primary source of mineral ores for the extraction of iodine, sodium, and potassium nitrates. NIDs have been relatively underexplored from a biological perspective. To address this, we collected sixteen soil samples from abandoned mines in Oficinas Pissis and Savona for chemical, mineralogical, and metagenomic analyses. The soils primarily consisted of halite and darapskite, with only one sample being predominantly composed of thenardite. Deliquescence and water activity measurements yielded values ranging from 0.02% to 0.40% and 0.47 to 0.62, respectively. To investigate the presence, identification, relative abundance, and diversity of microbial life in NID soils, we employed MiSeq high-throughput sequencing and bioinformatic tools. The dominant phyla observed were Firmicutes and Proteobacteria, with Actinobacteria and Cyanobacteria being predominant in two soil samples. Furthermore, we detected nitrate/perchlorate-reducing bacterial activity in enriched cultures from the soil samples. This study sheds light on the resilience of microbial life in the Atacama Desert NIDs, providing compelling evidence for its existence and offering insight into factors that could facilitate it within this unique environment. [ABSTRACT FROM AUTHOR]

Microorganisms are a valuable source of pharmaceutically active chemicals, serving as scaffolds for synthesis as well as lead structures. Investigating novel biomes frequently yields intriguing chemistry; the Atacama Desert in Chile is one such example. This study reports the isolation of a new reduced anthracycline-related compound from the Atacama Desert-derived bacterium Saccharothrix S26. Structural characterisation was achieved by one-dimensional and two-dimensional NMR, HR-LCMS, and X-ray crystallography. The compound was tested against the ESKAPE pathogens, bovine mastitis-related pathogens, and the fungal strain Cryptococcus neoformans, but no antimicrobial activity was observed. [ABSTRACT FROM AUTHOR]

Living in arid environments presents unique challenges to organisms, including limited food and water, extreme temperatures, and UV exposure. Reptiles, such as the South American leaf-toed gecko (Phyllodactylus gerrhopygus), have evolved remarkable adaptations to thrive in such harsh conditions. The gut microbiome plays a critical role in host adaptation and health, yet its composition remains poorly characterized in desert reptiles. This study aimed to characterize the composition and abundance of the gut microbiome in P. gerrhopygus inhabiting the hyperarid Atacama Desert, taking into account potential sex differences. Fecal samples from adult female and male geckos were analyzed by 16S rRNA gene amplicon sequencing. No significant differences in bacterial alpha diversity were observed between the sexes. However, the phylum Bacteroidota was more abundant in females, while males had a higher Firmicutes/Bacteroidota ratio. The core microbiome was dominated by the phyla Bacteroidota, Firmicutes, and Proteobacteria in both sexes. Analysis of bacterial composition revealed 481 amplicon sequence variants (ASVs) shared by female and male geckos. In addition, 108 unique ASVs were exclusive to females, while 244 ASVs were unique to males. Although the overall bacterial composition did not differ significantly between the sexes, certain taxa exhibited higher relative abundances in each sex group. This study provides insight into the taxonomic structure of the gut microbiome in a desert-adapted reptile and highlights potential sex-specific differences. Understanding these microbial communities is critical for elucidating the mechanisms underlying host resilience in Earth's most arid environments, and for informing conservation efforts in the face of ongoing climate change. [ABSTRACT FROM AUTHOR]

The Andean uplift and the concomitant aridification drove the rapid diversification of several plant lineages that were able to colonize warmer and drier habitats at low elevations and wetter and colder habitats at high elevations. These transitions may be facilitated by shifts in plant strategies to cope with drought and cold, which in turn can trigger episodes of accelerated species diversification. Here, we used four nuclear DNA markers to infer phylogenetic relationships of 80 Adesmia species of annuals, perennial herbs, shrubs and small shrubs that occur in Chile and Argentina. We reconstructed ancestral states for area, climatic niche and growth form to explore how Andean uplift and aridification promoted Adesmia diversification. We also performed logistic and linear regression analyses between different components of growth form (life span, woodiness and plant height) and climate. Finally, we estimated speciation rates across the phylogeny. Our results suggest that the ancestor of Chilean Adesmia was a perennial herb that probably originated in the high Andes of northern and central Chile. The low elevations of Central Chile were colonized in the late Miocene, whereas the high latitudes of Patagonia and the hyperarid coastal Atacama Desert were colonized repeatedly since Pliocene by lineages with different growth forms. Multiple and bidirectional transitions between annual and perennial habits and between herbaceous and woody habits were detected. These shifts were not correlated with climate, suggesting that the different growth forms are alternative and successful strategies to survive unfavorable seasons of both desert and high Andes. Net diversification analysis indicated a constant rate of diversification, suggesting that the high species diversity of Adesmia that occur in Chile is due to a uniform speciation process rather than to accelerated episodes of speciation.

Abstract The Atacama Desert’s naturally elevated metal(loid)s pose a unique challenge for assessing the environmental impact of mining, particularly for indigenous communities residing in these areas. This study investigates how copper mining influences the dispersion of these elements in the wind‐transportable fraction (

ABSTRACT Soil microorganisms mediate several biological processes through the secretion of natural products synthesized in specialized metabolic pathways, yet functional characterization in ecological contexts remains challenging. Using culture-independent metagenomic analyses of microbial DNA derived directly from soil samples, we examined the potential of biosynthetic gene clusters (BGCs) from six bacterial communities distributed along an altitudinal gradient of the Andes Mountains in the Atacama Desert. We mined 38 metagenome-assembled genomes (MAGs) and identified 168 BGCs. Results indicated that most predicted BGCs were classified as non-ribosomal-peptides (NRP), post-translational modified peptides (RiPP), and terpenes, which were mainly identified in genomes of species from Acidobacteriota and Proteobacteria phyla. Based on BGC composition according to types of core biosynthetic genes, six clusters of MAGs were observed, three of them with predominance for a single phylum, of which two also showed specificity to a single sampling site. Comparative analyses of accessory genes in BGCs showed associations between membrane transporters and other protein domains involved in specialized metabolism with classes of biosynthetic cores, such as resistance-nodulation-cell division (RND) multidrug efflux pumps with RiPPs and the iron-dependent transporter TonB with terpenes. Our findings increase knowledge regarding the biosynthetic potential of uncultured bacteria inhabiting pristine locations from one of the oldest and driest nonpolar deserts on Earth.IMPORTANCEMuch of what we know about specialized metabolites in the Atacama Desert, including Andean ecosystems, comes from isolated microorganisms intended for drug development and natural product discovery. To complement research on the metabolic potential of microbes in extreme environments, comparative analyses on functional annotations of biosynthetic gene clusters (BGCs) from uncultivated bacterial genomes were carried out. Results indicated that in general, BGCs encode for structurally unique metabolites and that metagenome-assembled genomes did not show an obvious relationship between the composition of their core biosynthetic potential and taxonomy or geographic distribution. Nevertheless, some members of Acidobacteriota showed a phylogenetic relationship with specific metabolic traits and a few members of Proteobacteria and Desulfobacterota exhibited niche adaptations. Our results emphasize that studying specialized metabolism in environmental samples may significantly contribute to the elucidation of structures, activities, and ecological roles of microbial molecules.

The region of Arica and Parinacota hosts unexplored remote sites with unique characteristics suitable for developing novel agricultural bioproducts. Notable locations include Jurasi Hot Springs, Polloquere Hot Springs, and Amuyo Lagoons, featuring open pools fed by thermal mountain springs. These geothermal sites harbor bacteria with plant growth-promoting activities, particularly interesting to the strains J19, TP22, A20, and A3. These bacteria possess in vitro plant growth-promoting traits, the ability to produce hydrolytic enzymes, and the capacity to inhibit phytopathogenic fungi. Moreover, they can tolerate different concentrations of NaCl and boron, making them suitable for developing new agricultural bioproducts for arid environments. The bacterial strains A3 and A20 have a positive effect on the growth of the aerial part of tomato plants (increased stem length, fresh and dry weight), with a significant increment in proline concentration and chlorophyll A and B content under saline conditions. Meanwhile, the strains J19 and TP22 exhibit herbicidal activity against Cenchrus echinatus by reducing root elongation and germination of the weed. These strains possess plant growth-promoting traits and improve plant resistance to salinity stress. They are promising candidates for developing innovative bio-based agricultural products suited to arid and semi-arid regions.

The increased availability of quality genomic data has greatly improved the scope and resolution of our understanding of the recent evolutionary history of wild species adapted to extreme environments and their susceptibility to anthropogenic impacts. The guanaco (Lama guanicoe), the largest wild ungulate in South America, is a good example. The guanaco is well adapted to a wide range of habitats, including the Sechura Desert, the high Andes Mountains to the north, and the extreme temperatures and conditions of Navarino Island to the south. Guanacos also have a long history of overexploitation by humans. To assess the evolutionary impact of these challenging habitats on the genomic diversity, we analyzed 38 genomes (∼10 to 16×) throughout their extensive latitudinal distribution from the Sechura and Atacama Desert to southward into Tierra del Fuego Island. These included analyses of patterns of unique differentiation in the north and geographic region further south with admixture among L. g. cacsilensis and L. g. guanicoe. Our findings provide new insights on the divergence of the subspecies ∼800,000 yr BP and document two divergent demographic trajectories and to the initial expansion of guanaco into the more southern portions of the Atacama Desert. Patagonian guanacos have experienced contemporary reductions in effective population sizes, likely the consequence of anthropogenic impacts. The lowest levels of genetic diversity corresponded to their northern and western limits of distribution and some varying degrees of genetic differentiation. Adaptive genomic diversity was strongly linked with environmental variables and was linked with colonization toward the south followed by adaptation. [ABSTRACT FROM AUTHOR]

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