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Plant spatial distribution is an important topic in ecology as it determines species coexistence and biodiversity dynamics. Usually, plants show clustered distributions in nature. Mistletoes are a good example of aggregated distributions, as they form dense aggregations due to several factors (availability of competent hosts, seed dispersal vectors, microclimate conditions).We analysed four native mistletoe species with divergent life histories and host ranges: Desmaria mutabilis and Tristerix corymbosus from the temperate rainforests of southern Chile; and Tristerix aphyllus and Tristerix verticillatus from the northern semi‐desert zone. While T. corymbosus and T. verticillatus have a wide host range, T. aphyllus and D. mutabilis are specialists that can parasitize only a few plant species. We hypothesized that specialized species would be more aggregated due to ecological and environmental restrictions. We used heterogeneous Poisson models to quantify spatial aggregation.Three of the four mistletoe species were spatially clustered at both environments, with aggregation being stronger in the temperate rainforest of southern Chile and particularly in the host‐specialist species. Our results suggest that environmental constraints are more important than ecological constraints (host range) in shaping mistletoe spatial structure.Mistletoe aggregated spatial distribution depends primarily on the environment that they inhabit, which conditions host spatial availability, and arrangement. [ABSTRACT FROM AUTHOR]

Desert areas in northern Chile are highly valuable ecosystems. While human activities are impacting the area in different ways, there are few environmental studies available. The current study analysed the ecological health status (water, sediment, biota) of a northern coastal area in the Atacama Region, including a national park (with a protected marine area), a tourist and benthic management area, and an industrial area. Results from the physical–chemical characterization and physiological state of organisms of ecological importance (macroalgae and microalgae) were integrated to determine pollution and toxic responses. The results identified high and moderate pollution levels for Bi, Ca, As, Ag and Cd in sediments. The As concentration in sediments is the leading environmental problem, with average values above the threshold effect level, associated with fine sediments. The stations showed increasing contamination and stress from north to south (national park > tourist and benthic management area > industrial area), associated with the proximity to the discharge of mining waste from the Salado River. The national park registered the poorest health status as demonstrated by high Cu bioaccumulation and high photosynthetic stress in the macroalgae and the lowest biomass concentration of the microalgae in water. The tourist and benthic management area demonstrated high As concentrations in sediments and Cd bioaccumulation. The industrial area was the least contaminated area, exhibiting lower photosynthetic stress and bioaccumulation. [ABSTRACT FROM AUTHOR]

Several strains were isolated from subsurface soil of the Atacama Desert and were previously assigned to the Micromonospora genus. A polyphasic study was designed to determine the taxonomic affiliation of isolates 4G51 T , 4G53, and 4G57. All the strains showed chemotaxonomic properties in line with their classification in the genus Micromonospora, including meso-diaminopimelic acid in the cell wall peptidoglycan, MK-9(H 4 ) as major respiratory quinone, iso-C 15:0 and iso-C 16:0 as major fatty acids and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as major polar lipids. The 16S rRNA gene sequences of strains 4G51 T , 4G53, and 4G57 showed the highest similarity (97.9 %) with the type strain of Micromonospora costi CS1-12 T , forming an independent branch in the phylogenetic gene tree. Their independent position was confirmed with genome phylogenies, being most closely related to the type strain of Micromonospora kangleipakensis. Digital DNA-DNA hybridization and average nucleotide identity analyses between the isolates and their closest phylogenomic neighbours confirmed that they should be assigned to a new species within the genus Micromonospora for which the name Micromonospora sicca sp. nov. (4G51 T =PCM 3031 T =LMG 30756 T ) is proposed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Platalina genovensiumThomas, 1928 is a bat commonly called Peruvian long-tongued bat. P. genovensium is characterized by having a greatly elongated muzzle, rostrum clearly longer than the braincase, and premaxillary bones projecting beyond the canines. The dorsal pelage is long and bicolored; the venter is lighter than the dorsum. P. genovensium is distributed from west of the Andes in Peru to northern Chile, with a few records reported from the Andes in Peru. It feeds in desert areas characterized by the presence of columnar cacti from which it obtains nectar and fruits; it has been recorded at elevations from near sea level up to about 2,600 m. It is listed as "Near Threatened" by the International Union for Conservation of Nature and Natural Resources. [ABSTRACT FROM AUTHOR]

Spatial heterogeneity in microbial communities is observed in all natural ecosystems and can stem from both adaptations to local environmental conditions as well as stochastic processes. Extremophile microbial communities inhabiting evaporitic halite nodules (salt rocks) in the Atacama Desert, Chile, are a good model ecosystem for investigating factors leading to microbiome heterogeneity, due to their diverse taxonomic composition and the spatial segregation of individual nodules. We investigated the abiotic factors governing microbiome composition across different spatial scales, allowing for insight into the factors that govern halite colonization from regional desert-wide scales to micro-scales within individual nodules. We found that water availability and community drift account for microbiome assembly differently at different distance scales, with higher rates of cell dispersion at the smaller scales resulting in a more homogenous composition. This trend likely applies to other endoliths, and to non-desert communities, where dispersion between communities is limited. At the intra-nodule scales, a light availability gradient was most important in determining the distribution of microbial taxa despite intermixing by water displacement via capillary action. [ABSTRACT FROM AUTHOR]

Background and Aim Quaternary glaciations strongly affected the distribution of species from arid and semi-arid environments, as temperature drops were accompanied by strong fluctuations in rainfall. In this study, we examined the response of xerophytic species to glacial cycles, determining the genetic patterns and climatic niche of Echinopsis chiloensis var. chiloensis , an endemic columnar cactus of arid and semi-arid regions of Chile. Methods We analysed 11 polymorphic microsatellites for 130 individuals from 13 populations distributed across the entire distribution of the species. We examined genetic diversity and structure, identified possible patterns of isolation by distance (IBD) and tested two competing population history scenarios using Approximate Bayesian Computation. The first scenario assumes a constant population size while the second includes a bottleneck in the southern population. The latter scenario assumed that the southernmost populations experienced a strong contraction during glaciation, followed by a postglacial expansion; by contrast, the area of the northernmost populations remained as a stable refugium. We also used ecological niche modelling (ENM) to evaluate the location and extension of suitable areas during the Last Glacial Maximum (LGM) and the mid-Holocene. Key Results We found a decline in genetic diversity towards high latitudes and a significant IBD pattern that together with ENM predictions suggest that E. chiloensis var. chiloensis experienced range contraction northwards during wet–cold conditions of the LGM, followed by expansion during aridification of the mid-Holocene. In addition to IBD, we detected the presence of a strong barrier to gene flow at 32°30′S, which according to coalescence analysis occurred 44 kyr BP. The resulting genetic clusters differed in realized climatic niche, particularly in the variables related to precipitation. Conclusions Our results suggest that the cactus E. chiloensis var. chiloensis experienced range contraction and fragmentation during the wet–cold conditions of the LGM, which may have facilitated ecological differentiation between northern and southern populations, promoting incipient speciation. [ABSTRACT FROM AUTHOR]

The climate of the Coquimbo Region, north-central Chile is driven by atmospheric, oceanic and orographic factors. The southeast Pacific anticyclone, the cold Humboldt Current and the rugged topography that characterize the zone, determine thermally induced wind regimes and the formation of low stratocumulus along the coastline. Low precipitation and high solar radiation cause important climatic altitudinal gradients, especially on temperature and humidity, thus different climatic areas can be identified in the region. We summarized the general climatic characteristics of the study area and analyzed meteorological data to understand the behavior of the environmental variables. We used mesoscale modeling to evaluate the spatial characteristics of the mean air temperature, humidity and wind. These atmospheric variables present a strong elevation gradient. The particular topographic characteristics of the region favor the development of a thermally induced wind regime, where land and sea breezes and valley winds are observed. [ABSTRACT FROM AUTHOR]

Aim The Chilean endemic Dioscorea biloba (Dioscoreaceae) is a dioecious geophyte that shows a remarkable 600 km north-south disjunction in the peripheral arid area of the Atacama Desert. Its restricted present-day distribution and probable Neogene origin indicate that its populations have a history linked to that of the Atacama Desert, making this an ideal model species with which to investigate the biogeography of the region. Location Chile, Atacama Desert and peripheral arid area. Methods Two hundred and seventy-five individuals from nine populations were genotyped for seven nuclear microsatellite loci, and plastid trnL-F and trnT-L sequences were obtained for a representative subset of these. Analyses included the estimation of genetic diversity and population structure through clustering, Bayesian and analysis of molecular variance analyses, and statistical parsimony networks of chloroplast haplotypes. Isolation by distance was tested against alternative dispersal hypotheses. Results Microsatellite markers revealed moderate to high levels of genetic diversity within populations, with those from the southern Limarí Valley showing the highest values and northern populations showing less exclusive alleles. Bayesian analysis of microsatellite data identified three genetic groups that corresponded to geographical ranges. Chloroplast phylogeography revealed no haplotypes shared between northern and southern ranges, and little haplotype sharing between the two neighbouring southern valleys. Dispersal models suggested the presence of extinct hypothetical populations between the southern and northern ranges. Main conclusions Our results are consistent with prolonged isolation of the northern and southern groups, mediated by the life-history traits of the species. Significant isolation was revealed at both large and moderate distances as gene flow was not evident even between neighbouring valleys. Bayesian analyses of microsatellite and chloroplast haplotype diversity identified the southern area of Limarí as the probable area of origin of the species. Our data do not support recent dispersal of D. biloba from the southern range into Antofagasta, but indicate the fragmentation of an earlier wider range, concomitant with the Pliocene-Pleistocene climatic oscillations, with subsequent extinctions of the Atacama Desert populations and the divergence of the peripheral ones as a consequence of genetic drift. [ABSTRACT FROM AUTHOR]

Quartz stones are ubiquitous in deserts and are a substrate for hypoliths, microbial colonists of the underside of such stones. These hypoliths thrive where extreme temperature and moisture stress limit the occurrence of higher plant and animal life. Several studies have reported the occurrence of green hypolithic colonization dominated by cyanobacteria. Here, we describe a novel red hypolithic colonization from Yungay, at the hyper-arid core of the Atacama Desert in Chile. Comparative analysis of green and red hypoliths from this site revealed markedly different microbial community structure as revealed by 16S rRNA gene clone libraries. Green hypoliths were dominated by cyanobacteria ( Chroococcidiopsis and Nostocales phylotypes), whilst the red hypolith was dominated by a taxonomically diverse group of chloroflexi. Heterotrophic phylotypes common to all hypoliths were affiliated largely to desiccation-tolerant taxa within the Actinobacteria and Deinococci. Alphaproteobacterial phylotypes that affiliated with nitrogen-fixing taxa were unique to green hypoliths, whilst Gemmatimonadetes phylotypes occurred only on red hypolithon. Other heterotrophic phyla recovered with very low frequency were assumed to represent functionally relatively unimportant taxa. [ABSTRACT FROM AUTHOR]

A systematic programme of surveys for entomopathogenic nematodes (EPN) was done in Chile between 2006 and 2008. The survey spanned the principal ecosystems of mainland Chile as well as a number of islands, and covered a wide range of habitats including the Atacama Desert, Andean Altiplano, temperate rainforests and subpolar territory. Nearly 1400 soil samples were collected, of which 7% were positive for EPN. Of 101 EPN isolates obtained, 94 were Steinernema spp. and seven were Heterorhabditis sp. Of the 94 Steinernema isolates, 39 were identified as Steinernema feltiae, the remainder being distributed between two new species, S. unicornum (52 records) and S. australe (three records). The Heterorhabditis isolates, all designated as Heterorhabditis sp.1, are referred to herein as H. cf. safricana. Steinernema feltiae and S. unicornum were collected predominately in the south of Chile and were obtained from a range of habitats, including forests, open grassland, montane soils and coastal zones; neither species was recovered from the far north of the country (viz., desert soils in the Norte Grande region). Steinernema australe was found in only three soil samples, all from humid, cool, coastal localities in the south. Heterorhabditis cf. safricana was recovered from the northern regions, with most isolates found in or on the periphery of the Atacama Desert; they were not recovered from cooler, more humid regions of southern Chile. Molecular information indicated there were two subgroups of both S. unicornum and S. feltiae, with a geographical, intraspecific split of subgroups between the most southerly and the more central survey zones. All isolates were collected by ex situ baiting with waxmoth larvae and the natural hosts are unknown. [ABSTRACT FROM AUTHOR]

Abstract: In desert environments with low water and salt contents, rapid thermal variations may be an important source of rock weathering. We have obtained temperature measurements of the surface of rocks in hyper-arid hot and cold desert environments at a rate of 1/s over several days. The values of temperature change over 1-second intervals were similar in hot and cold deserts despite a 30 °C difference in absolute rock surface temperature. The average percentage of the time dT/dt>2 °C/min was ~8±3%, >4 °C/min was 1±0.9%, and >8 °C/min was 0.02±0.03%. The maximum change over a 1-second interval was ~10 °C/min. When sampled to simulate data taken over intervals longer than 1 s, we found a reduction in time spent above the 2 °C/min temperature gradient threshold. For 1-minute samples, the time spent above any given threshold was about two orders of magnitude lower than the corresponding value for 1-second sampling. We suggest that a rough measure of efficacy of weathering as a function of frequency is the product of the percentage of time spent above a given threshold value multiplied by the damping depth for the corresponding frequency. This product has a broad maximum for periods between 3 and 10 s. [Copyright &y& Elsevier]

The whole poetic work of Raúl Zurita (National Prize of Literature, 2000) tells about God search. In this way it is crossed by the biblical intertextuality. His poetical and vital project takes from Dante the scheme: hell-purgatory- paradise, in order to construct the way from a present of pain and self-destruction to the glimpse of happiness. In the section "Pastoral of Chile" of the book "Anteparaíso" (1982) Zurita talks to some biblical prophets, especially to Oseas, who preaches in Israel during the Eighth Century b. C. And the poet prophesies in Chile when it was under military dictatorship. The present study intends to tell us about the intensity and peculiarities of this dialogue between poetry and theology, whose meeting aims to get to the bottom of the question about the last sense of human existence, that nests in each authentic work of art. [ABSTRACT FROM AUTHOR]

The Atacama Desert in Chile-hyperarid and with high-ultraviolet irradiance levels-is one of the harshest environments on Earth. Yet, dozens of species grow there, including Atacama-endemic plants. Herein, we establish the Talabre-Lejía transect (TLT) in the Atacama as an unparalleled natural laboratory to study plant adaptation to extreme environmental conditions. We characterized climate, soil, plant, and soil-microbe diversity at 22 sites (every 100 m of altitude) along the TLT over a 10-y period. We quantified drought, nutrient deficiencies, large diurnal temperature oscillations, and pH gradients that define three distinct vegetational belts along the altitudinal cline. We deep-sequenced transcriptomes of 32 dominant plant species spanning the major plant clades, and assessed soil microbes by metabarcoding sequencing. The top-expressed genes in the 32 Atacama species are enriched in stress responses, metabolism, and energy production. Moreover, their root-associated soils are enriched in growth-promoting bacteria, including nitrogen fixers. To identify genes associated with plant adaptation to harsh environments, we compared 32 Atacama species with the 32 closest sequenced species, comprising 70 taxa and 1,686,950 proteins. To perform phylogenomic reconstruction, we concatenated 15,972 ortholog groups into a supermatrix of 8,599,764 amino acids. Using two codon-based methods, we identified 265 candidate positively selected genes (PSGs) in the Atacama plants, 64% of which are located in Pfam domains, supporting their functional relevance. For 59/184 PSGs with an Arabidopsis ortholog, we uncovered functional evidence linking them to plant resilience. As some Atacama plants are closely related to staple crops, these candidate PSGs are a "genetic goldmine" to engineer crop resilience to face climate change., Competing Interests: The authors declare no competing interest.

Arica is a coastal city located in northern Chile, in the Atacama Desert. The behavior of surface temperatures in the city between 1985 and 2019 was studied using Landsat satellite images, leading to the identification of surface urban heat islands (SUHI), surface urban cold islands (SUCI), and average temperature zones. The higher intensities of the SUHI reach values of almost 45 °C and the SUCI lower values are below 13 °C. From the socioeconomic characterisation of the population based on indicators retrieved from the 2012 and 2017 population censuses, we identified that during the study period there was a lower presence of SUHI, but these were linked to spaces of lower socioeconomic level and, for the most part, would form new urban spaces within the city. On the other hand, SUCI had a greater spatial presence in the study area and in the urban morphology, being found mostly in areas of high socioeconomic level and in consolidated spaces with few possibilities of generating new constructions. [ABSTRACT FROM AUTHOR]

During a study of the fungi from a semi-arid region of northern Chile, a novel species of Aspergillus was encountered in the soil from an area where pepper trees ( Schinusmolle ) were growing. Marker genes were sequenced to identify these isolates. The β-tubulin, calmodulin and DNA-dependent RNA polymerase loci all indicated that this was a novel species in Aspergillus section Nidulantes and in the Aspergillus multicolor clade. The new species was studied morphologically and differences between it and the other members of the A. multicolor clade are described. We provide a name and description for these isolates as Aspergillus incahuasiensis sp. nov.