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This paper has been written following the results and reflections of the previously published paper (Viguier et al., 2018) detailing a multidisciplinary assessment of the groundwater resources in the northern part of the Pampa del Tamarugal Aquifer (PTA), at Atacama Desert (Northern Chile). This short note aims to propose an overall review of the PTA conceptual model. Following a brief description of the PTA limit changes over 60 years, the boundary conditions, recharge processes and the 2012–2015 piezometric map are detailed in an updated hydrogeological conceptual model including the northern, central and southern parts of the aquifer. The exploited aquifer contained in El Diablo Fm (Miocene alluvial filling) covers almost 6420 km2, i.e. +87% compared to a previous study. That means that the groundwater resources in the Central Depression are today still underestimated. The Andean Piedmont appears to be a highly interesting target for the groundwater resource exploration and for the long-term water supply in the Central Andes where the regional water demand is continuously increasing. • An overall review of the Pampa del Tamarugal Aquifer conceptual model is proposed. • The updated PTA extent covers almost 6420 km2 (+87%). • Groundwater resources are underestimated in the Central Depression. • The Andean Piedmont is a strategic target for the exploration of groundwater resources. [ABSTRACT FROM AUTHOR]

Abstract: Fog is a potential source of water that could be exploited using the innovative technology of fog collection. Naturally, the potential of fog has proven its significance in cloud forests that are thriving from fog interception. Historically, the remains of artificial structures in different countries prove that fog has been collected as an alternative and/or supplementary water source. In the beginning of the 19th century, fog collection was investigated as a potential natural resource. After the mid-1980s, following success in Chile, fog-water collection commenced in a number of developing countries. Most of these countries are located in arid and semi-arid regions with topographic and climatic conditions that favour fog-water collection. This paper reviews the technology of fog collection with initial background information on natural fog collection and its historical development. It reviews the climatic and topographic features that dictate fog formation (mainly advection and orographic) and the innovative technology to collect it, focusing on the amount collected, the quality of fog water, and the impact of the technology on the livelihoods of beneficiary communities. By and large, the technology described is simple, cost-effective, and energy-free. However, fog-water collection has disadvantages in that it is seasonal, localised, and the technology needs continual maintenance. Based on the experience in several countries, the sustainability of the technology could be guaranteed if technical, economic, social, and management factors are addressed during its planning and implementation. [Copyright &y& Elsevier]

Abstract: In South America, the arid and semiarid subtropical regions through the Atacama Desert and north-central Chile between 19° and 32°S are currently a gap in the tree-ring chronology network. Only a short tree-ring chronology has been published for this vast region and little is known about the suitability of many woody species for tree-ring analysis and dendroclimatology. In this paper we present the first detailed analysis of the climate responses and influences of the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) on the tree-rings of three species new to dendrochronology and that typically occur at high elevations in the Andes of central and north-central Chile. Three well-replicated tree-ring chronologies of Kageneckia angustifolia, Proustia cuneifolia and Fabiana imbricata are compared with century-long regional records of precipitation and temperature, and with the N3.4 SST and PDO indices in both time and frequency-domains using correlation and wavelet analysis. The radial growth of these species is controlled by winter precipitation and is also positively correlated with temperature during most of the rainy season from April to September (autumn–spring). The regional climate as well as tree growth is strongly modulated by ENSO and ENSO-like conditions in the equatorial Pacific at both interannual and interdecadal timescales. The decadal and interdecadal variability is not correlated with PDO and appears to be related to the Interdecadal Pacific Oscillation (IPO), a Pacific-wide ENSO-like mode of climate variability. Despite their relatively short lifespans, these three new species have a high potential for dendrochronological and dendroclimatic studies in the semiarid region of Chile over the last two centuries. [Copyright &y& Elsevier]

Agrichemical contamination can provoke evolutionary responses in freshwater populations. It is a particularly relevant issue in semi-arid regions due to the sensitivity of endemic species to pollutants and to interactions with temperature stress. This paper investigates the presence of pesticides in rivers within a semi-arid agricultural watershed of Chile, testing for their effects on population genetic characteristics of the endemic mayfly Andesiops torrens (Insecta, Ephemeroptera). Pesticides were detected in sediment samples in ten out of the 30 sites analyzed throughout the upper part of the Limarí watershed. To study the evolutionary impact of such contamination on A. torrens , we used a genome-wide approach and analyzed 2056 single nucleotide polymorphisms (SNPs) loci in 551 individuals from all sites. Genetic differentiation was weak between populations, suggesting high gene flow across the study area. While we did not find evidence of pesticide effects on genetic diversity nor on population differentiation, the allele frequency of three outlier SNP loci correlated significantly with pesticide occurrence. Interrogation of genomic resources indicates that two of these SNPs are located within functional genes that encode for the low-density lipoprotein receptor-related protein 2 and Dumpy, both potentially involved in insect cuticle resistance processes. Such genomic signatures of local adaptation are indicative of past adverse effects of pesticide exposure on the locally adapted populations. Our results reveal that A. torrens is sensitive to pesticide exposure, but that a high gene flow may confer resilience to contamination. This research supports the contention that A. torrens is an ideal model organism to study evolutionary responses induced by pesticides on non-target, endemic species. Image 1 • Pesticide contamination was detected in sediments from the Chilean Limarí watershed. • Andesiops torrens populations exposed to pesticides show genetic adaptive responses. • Pesticide exposure alters allele frequency of three single nucleotide polymorphism loci. • Potential candidate genes are involved in insect cuticle resistance. • Gene flow is high within the watershed and not altered by pesticide contamination. Pesticide contamination, revealed for the first time in the Limarí watershed, causes adaptive differentiation in an endemic mayfly species despite high gene flow. [ABSTRACT FROM AUTHOR]