Desert Conditions Research Articles

Effect of planting geometry and chemical fertilizers on growth characteristics, essential oil yield and composition of Inula racemosa under cold desert conditions of western Himalayas

Inula racemosa, a critically endangered medicinal plant of the western Himalayas, is known for its various industrial uses worldwide. Fertilizer application contributes to higher crop yield; however, their excessive use may lead to higher cost of cultivation and environmental pollution. Similarly, appropriate plant orientation significantly contributes to utilizing natural resources efficiently, leading to higher yields. Therefore, the study aimed to optimize the fertilizer dose for I. racemosa with a suitable planting geometry. A field experiment was carried out in the cold desert region of the western Himalayas comprising three planting geometries 30 × 30 cm (G1), 30 × 45 cm (G2) and 45 × 45 cm (G3) and four fertilizer doses (NPK) at the rates of 0 (F1), 90:60:30 kg ha−1 (F2), 120:75:40 kg ha−1 (F3), and 150:90:50 kg ha−1 (F4) from 2021 and 2022. The experiment was laid out in a split-plot design with 12 treatment combinations and replicated thrice. Planting geometry significantly affected all the parameters studied except the number of secondary roots and essential oil (EO) content. Planting geometry G2 recorded significantly higher values of all the morphological and yield traits; however, the lowest were observed in G1, except for plant height. Among fertilizer doses, F4 produced better results for all the growth and root yield components, whereas the control presented the lowest values. The highest fertilizer dose F4 resulted in dry root yield that were 6.34, 26.15 and 102.99% greater than those of F3, F2, and the control, respectively. The plants fertilized with NPK @ 150:90:50 kg ha−1 produced significantly highest EO yield, which was 125.40% greater than that of the control. The major EO constituents alantolactone, isoalantolactone, and β-elemene ranged from 59.44–63.65, 31.38–34.68 and 0.24–0.33%, respectively; however, their accumulation patterns were not consistent. Thus, a planting geometry of 30 × 45 cm in combination with NPK @ 150:90:50 kg ha−1 could improve the growth, dry root yield and EO yield of I. racemosa, which may encourage farmers in cold arid regions for cultivation and consequently aid in achieving its conservation, in addition to meeting ever-increasing industrial demand. Graphical

Novel identification of telocytes in the skin of the desert tortoise (Testudo graeca): A correlative study using semithin section, transmission electron microscopy, and immunofluorescence.

Novel identification of telocytes in the skin of the desert tortoise (Testudo graeca): A correlative study using semithin section, transmission electron microscopy, and immunofluorescence.

Phytochemical Screening of Calligonum polygonoides Stem Extract Collected from Jaisalmer District of Rajasthan, India

This study aimed to qualitatively analyze the hydroalcoholic stem extracts of Calligonum polygonoides to identify major secondary metabolites with potential pharmacological significance. C. polygonoides, commonly known as “Phog” a plant native to the arid regions of Rajasthan, India, thrives under extreme desert conditions characterized by high temperatures, intense solar radiation, and limited water availability. This study aimed to qualitatively analyze the hydroalcoholic stem extracts of C. polygonoides to identify major secondary metabolites with potential pharmacological significance. Plant samples were collected from Chelak Village, Jaisalmer, a region within the Thar Desert, where plants have evolved unique biochemical adaptations to survive harsh environmental stresses. The stem of C. polygonoides was collected, dried, and ground into a fine powder, followed by hydroalcoholic extraction. Standard phytochemical tests were conducted to detect key bioactive compounds. The qualitative screening confirmed the presence of flavonoids, tannins, phenolic compounds, saponins, sterols, quinones, glycosides, and alkaloids in the stem extracts. These secondary metabolites are renowned for their diverse therapeutic properties, comprising anti-oxidant, anti-inflammatory, antimicrobial, and anticancer properties. The occurrence of these bioactive compounds in C. polygonoides underscores its potential as a valuable source of plant-derived pharmaceuticals. The ability of this plant to produce a rich array of phytochemicals despite extreme desert conditions suggests its evolutionary adaptation to environmental stress, which may contribute to its medicinal properties. This study highlights the significance of exploring desert flora for novel bioactive compounds that could lead to the development of sustainable, plant-based therapeutic agents.

A Framework to Integrate Performance of Helmet Systems for Blast Overpressure, Blunt Impact, and Thermal Loading

Abstract Helmets have evolved through improvements in shell and suspension materials, and better designs that can absorb ballistic and blunt impact energy. In the past 20 years, threats to US Warfighters have increased with the prevalence of buried improvised explosive devices (IED) simultaneous producing overpressure, blunt and ballistic impact effects, as well as thermal loading in extreme desert conditions. The literature to date, does not show any research that integrates multiple types of loading in helmet system design and performance analysis. The scope of this paper is to integrate such loadings into a design framework that enables trade space analysis across multiple threats. Blunt impact and blast overpressure loadings are simulated using computational fluid dynamics and structural mechanics approaches presented by the authors earlier. The thermal loading and its effects are modeled as forced convection due to ambient directional winds to assess each design?s efficiency in facilitating evaporative cooling via perspiration and quantified by transport of moisture-laden air away from the head. Blast overpressure and blunt impact loadings, along with thermal loading, are used for multiple configurations of the helmet suspension system as representative cases. The results from the simulated cases are integrated within a framework combining the effects of the loadings to assess helmet system design. We consider two different configurations of helmet systems in this paper and present the results in detail.

Optimization of cereal productivity and physiological performance under desert conditions: varying irrigation, salinity and planting density levels.

Adequate irrigation with low-quality water, aligned with the specific water requirements of crops, will be critical for the future establishment of cereal crops on marginally fertile soils. This approach is essential to support global food security. To identify suitable cereal species and genotypes for these challenging conditions with the aim of optimizing yield and resilience, three different cereal species were tested under sandy soil conditions at the experimental fields of ICBA (Dubai, UAE). The experimental design employed a factorial combination split-plot arrangement including five primary factors: crop species (barley, triticale and finger millet), genotypes (3 in barley, 3 in triticale and 2 in finger millet), salinity levels (2 and 10 dS m-1), irrigation levels (100%, 150%, and 200% ETo), and planting densities (30 and 50cm of spacing between rows). Agronomic parameters (e.g. plant height, grain yield, total plant dry weight and harvest index) and physiological parameters [Normalized Difference Vegetation Index (NDVI) readings, together with nitrogen and carbon concentration isotopic composition, chlorophyll, flavonoids, and anthocyanins concentrations in flag leaves and the Nitrogen Balance Index (NBI)] exhibited distinct genotypic responses across the species investigated. Regarding grain yield, salt stress did not impact barley and finger millet, whereas triticale experienced a reduction of nearly one third of its yield. Increased irrigation led to higher grain yields only in barley, while increased planting density significantly improved grain yield across all species examined demonstrating its potential as a simple agronomic intervention. Physiological responses highlighted reduced nitrogen isotope composition under both salt stress and higher planting density in all species. Nevertheless, the response to irrigation varied among species exhibiting significant negative correlations with aerial plant dry matter. In contrast, carbon isotope composition did not display a clear pattern in any of the species studied under different agronomic treatments. These results underscore the importance of selecting salt and drought tolerant species and optimizing planting density to maximize productivity on marginal soils. Future research should focus on refining irrigation strategies and identification of high-performing genotypes to improve cereal cultivation in arid regions, contributing to global food security.

Leaf characteristics and morphophysiological features of selected vascular plants in goltsy deserts of the Khibiny Mountains (Kola Peninsula)

The stability of biota in the extreme conditions of the goltsy deserts during ongoing climate change is determined by the adaptive characteristics of individual species. This study aimed to assess the characteristics of vascular plants (Salix polaris, Salix hastata, Saxifraga oppositifolia, Carex bigelowii, and Luzula arcuata) to the conditions of existence in the Khibiny goltsy deserts. The assessment was based on the morphological and anatomical leaf structures, pigment content and the intensity of photosynthesis. Biomorphological adaptations of high-altitude plants include miniaturization, plagiotropy, and compactization. The leaves of the studied plant species in the goltsy deserts exhibit features characteristic of mesophytes and xerophytes. For deciduous shrubs, a dorsoventral leaf structure with a high palisade coefficient was observed. For herbaceous perennials, a homogeneous type of mesophyll structure with a uniform distribution of chloroplasts and a thick cuticle was observed. The chlorophyll and carotenoid content ranges were comparable to those of the same species in the Khibiny mountain tundra belt and the Arctic tundra of Western Svalbard, indicating genetic determinism in the chlorophyll content of these species. The highest values of photosynthetic activity were found in graminoids (Carex bigelowii and Luzula arcuata) and Salix polaris. The characteristics of these species provide greater stability in the extreme conditions of the goltsy deserts and under climate change. Saxifraga oppositifolia exhibited the lowest values of photosynthetic activity.

Seismic Data Acquisition Utilizing a Group of UAVs

Seismic exploration in hard-to-reach hazardous environments like deserts is a very expensive and time-consuming process that involves a lot of human resources and equipment. These difficulties can be overcome with the implementation of robots, providing flexible mission design, safe operation, and high precision data acquisition. This work presents an autonomous robotic system to assist seismic crews in advanced data acquisition for near-surface characterization, shallow cavity detection, and acquisition grid infill. The developed system consists of a swarm control station and a swarm of unmanned aerial vehicles (UAVs) equipped with seismic sensors. The architecture of the swarm control station, its individual blocks, features of UAV exploitation for seismic data acquisition tasks, hardware and software tool limitations are considered. Algorithms for planning UAV swarm flight paths, their comparison and trajectory examples are presented. Experiments utilizing 9 and 16 UAVs to record 171 and 144 target points, respectively, in harsh desert conditions are described. The results demonstrate the feasibility of the proposed system for seismic data acquisition. The developed robotic system offers flexibility in seismic survey design and planning, enabling efficient coverage of vast areas and facilitating comprehensive data acquisition, which enhances the accuracy and resolution of subsurface seismic imaging.

Spatiotemporal Dynamics of Bacterial Community Assembly and Co-Occurrence Patterns in Biological Soil Crusts of Desert Ecosystems.

Biological soil crusts (BSCs) play a fundamental role in desert ecosystems by stabilizing soil, cycling nutrients, and retaining moisture. However, the assembly processes governing bacterial communities within BSCs remain largely unknown. This study aimed to reveal the spatiotemporal variations in the bacterial community diversity, co-occurrence patterns, and ecological assembly processes of BSCs and their underlying soils across different desert and seasonal conditions. We systematically analyzed the spatial differences in the bacterial diversity, co-occurrence networks, and community assembly processes of BSCs and their underlying soils using samples collected at various soil depths from different BSC types in different deserts. We discovered that BSC type and soil depth were the primary factors driving bacterial community assembly, while seasonal effects were weaker and more indirect, and mainly regulated community dynamics through changes in resource availability and environmental conditions. The underlying soils of moss- and lichen-BSCs exhibited higher bacterial diversity and richness than those of algae BSCs. In contrast, cyano-BSCs exhibited a lower diversity, but Cyanobacteria demonstrated the highest photosynthetic function. Among the different deserts, the community assembly of samples from the eastern Inner Mongolia deserts was largely influenced by environmental selection, whereas stochastic processes were more prominent in the central and western desert regions. A β-nearest taxon index (βNTI) analysis indicated that stochastic processes were dominant in surface BSC samples, while environmental selection played a stronger role in deeper layers. A co-occurrence network analysis revealed that surface BSC samples had a high degree of network connectivity, with those from moss- and lichen-BSCs being particularly high, and they also exhibited high modularity and local clustering that promoted the functional stability of the microbial communities. This study revealed the integrated effects of soil depth, BSC type, desert type, and resource availability on microbial community assembly in desert ecosystems. These findings provide a theoretical basis for the microbial management of BSCs and scientific insights to support restoration strategies in desert ecosystems.

Contaminant bioaccessibility in abandoned mine tailings in Namibia changes along a climatic gradient.

Fine-grained dust from tailing storage facilities in abandoned sulfide-ore mining areas represents an important source of environmental contamination. Fine fractions (<48 μm and <10 μm) of tailings from three old mining sites situated along a climatic gradient from hot semiarid to cold desert conditions in Namibia were studied: Kombat (Cu-Pb-Zn; rainfall ∼500 mm), Oamites (Cu; ∼120 mm), Namib Lead & Zinc (Pb-Zn; ∼0 mm). Multi-method mineralogical and geochemical investigations were adopted to assess the binding and gastric bioaccessibility of the metal(loid)s and to evaluate the associated human health risks. The total concentrations of contaminants in the tailings generally increased with the decreasing particle size (up to 134 mg As kg-1, 14 900 mg Cu kg-1, 8880 mg Pb kg-1, 13 300 mg Zn kg-1). The mean bioaccessible fractions varied substantially between the sites and were significantly higher for the tailings from the sites with a higher rainfall (73-82% versus 22%). The mineralogical composition of the tailings, reflecting the original mineralogy and the degree of the weathering process, is the main driver controlling the bioaccessibility of the metal(loid)s. In desert environments, metal(loid)s in tailings are bound in sulfides or sequestered in secondary Fe oxyhydroxides and/or Fe hydroxysulfates, all of which are insoluble in simulated gastric fluid. In contrast, tailings from areas with higher precipitation contain metal(loid)s hosted in carbonate phases (malachite, cerussite), which are highly soluble under gastric conditions. Based on the higher contaminant bioaccessibility, the vicinity of the settlement and farmlands, and a higher percentage of wind-erodible fine particles, a higher risk for human health has thus been identified for the Kombat site, where further remediation of the existing tailings storage facility is highly recommended.

Native dendroflora of Western Kazakhstan at introduction in the Mangistau desert

The article is devoted to the study of the indigenous dendroflora of Western Kazakhstan and its introductioninto the desert conditions of Mangistau. The flora of the Mangistau region includes 770 species of higherspore and vascular plants belonging to 333 genera and 73 families. In Atyrau region, 899 species of highervascular plants have been recorded, associated with 351 genera and 85 families. Indigenous woody plantscomprise 7.8 % of the total flora in the Atyrau region and 16.7 % in the Mangistau region, indicating theirlow representation in the vegetation cover. The status of natural populations of six woody fruit and berry specieshas been studied: Crataegus ambigua, Crataegus altaica, Rosa laxa, Rosa iliensis, Ribes aureum, andLonicera tatarica. The selection of representatives of the indigenous dendroflora of Western Kazakhstan hasbegun for the formation of a collection, which includes 14 species, four of which are rare and endangered,listed in the Red Book of Kazakhstan. It analyzes indigenous woody plants, their nutritional, medicinal, andecological functions, as well as their potential for ecosystem restoration and ensuring food security.

Analysis and performance enhancement of photovoltaic water pumping system under desert condition in Algeria

This paper presents a comprehensive study and analysis of a stand-alone photovoltaic (PV) pumping system for irrigation in the semi-arid location (Sebseb: Ghardaia, Algeria). The research includes a daily efficiency analysis of the solar PV pump, offering in-depth insights into the system's operation, especially focusing on the pump's performance throughout a typical day, based on the current solar panel configuration. The paper highlights the variation in energy absorbed and produced by the pump, as well as the system's efficiency during the day. It also compares on-site measured data with a full-year simulation using PVsyst software. The analysis considers the size of the main components, water needs, and experimental data to evaluate the system's performance and identify the most efficient configuration, focusing on factors including solar radiation, pumped water volume, performance ratio, and pump efficiency. The proposed configuration results in a 17% improvement in system performance and a 9.5% enhancement in pump efficiency.

Anatomical and physiological properties of the dromedary: A potential sustainability alternative and a vital asset in the era of climate change

The one-humped camel (Camelus dromedarius), commonly referred to as the Arabian camel, is primarily found in North Africa, tropical Africa, the Middle East, and the Indian subcontinent. The dromedary camel is of immense economic, social, and ecological value to nomadic and rural communities, offering high-quality animal protein through milk and meat and serving as a vital means of transportation. In some places, camels are also expected to enhance local tourism, providing much-needed financial support to the local economy. Owing to their unique qualities, camels are essential for maintaining desert ecosystems, setting them apart from other domestic livestock. The adaptations of dromedaries are tailored for survival in harsh environments with limited water and food, extreme heat, and rugged terrain. These adaptations include specialized skin, eyes, nostrils, lips, large bodies, long legs, and wide foot pads. Additionally, the biological, physiological, and biochemical traits of camels and their behavioral adaptations contribute to their resilience in desert conditions. These adaptations include water conservation, unique blood properties, thermoregulation, and efficient digestion and metabolism. Furthermore, the feeding, drinking, thermal, and reproductive behaviors of camels significantly support survival in deserts. The anatomical and physiological characteristics of the dromedary make it the ideal animal to meet the needs of users globally, especially amid climate change, where global warming, water scarcity, and scarce pastures are common. Therefore, camels are crucial for stabilizing the food supply in arid desert regions, nourishing their keepers, and serving as vital contributors to food security and sovereignty within desert ecosystems.

Possible phylogenetic relationships of Gymnarrhena (Gymnarrheneae, Gymnarrhenoideae, Asteraceae) based on comparative carpology

The amphicarpic annual Gymnarrhena micrantha (Asteraceae), inhabiting the deserts of North Africa to the Middle East, is interesting not only for its unusual biology, but also for its peculiar morphological structure. The monotypic genus Gymnarrhena, with uncertain position in the Asteraceae for a long time, is currently included in the tribe Gymnarrheneae and a separate subfamily Gymnarrhenoideae. The objective of the study was to examine fruit and seed structure in G. micrantha to consider possible phylogenetic relationships of the genus based on carpological characters. It was found that fruit structural organization in G. micrantha, with simply arranged pericarp and seed coat, parenchymatous and poorly differentiated on the tissue, corresponds to that of the early diverging evolutionary lines of Asteraceae, in which the states of these characters are considered to be plesiomorphic in the family. It has been suggested that taxonomically important structural features of Gymnarrhena cypsela include the structure of the apical region, pericarp and seed coat, the place of pappus attachment and its structure, the type of pappus hygroscopic tissue, and morphophysiological features of receptacular bracts surrounding the cypsela. The study did not confirm the relationship of Gymnarrhena with the tribes Corymbieae and Cichorieae, the seed coat of which differs markedly from the seed coat of Gymnarrhena in the presence of fine porosity of the exotesta cell walls. A set of the anatomical and carpological characters indicates a possible relationship of Gymnarrhena with the basal subtribes Cardopatiinae and Carlininae of the tribe Cardueae. The morphophysiological adaptation of G. micrantha and Cousiniopsis atractyloides cypselae to dissemination in desert conditions, similar in structural details, apparently suggests a close relationship between the subfamilies Gymnarrhenoideae and Carduoideae.

The apparatus for atmospheric water harvesting in an arid climate - Prototype design and testing in laboratory conditions

The apparatus for atmospheric water harvesting in an arid climate - Prototype design and testing in laboratory conditions

Fixing active sand dune by native grasses in the desert of Northwest China

BackgroundDesertification is the most severe environmental problem in arid and semi-arid regions and has caused great economic loss every year. However, artificial sand fixation barriers function on sand fixation for only 10–20 years. Searching for a native species with long-term sand fixation effect and strong environmental adaptive capacity, and low water consumption is needed. In this study, we investigated the environmental adaption and sand fixation effect of a grass from Poaceae family (Psammochloa villosa) that is indigenous to the desert of Northwest China.ResultsThe results showed that P. villosa has a streamlined leaf form, strong mechanical strength, and flexibility to adapt to wind. Leaf curling of P. villosa under drought decreased water loss rate through decreased evaporation area to adapt to drought. Significant negative relationship between adventitious root length and horizontal root burial depth indicates that adventitious roots help P. villosa absorb water and nutrients from soil under shallow sand burial condition, which enables P. villosa to adapt to different sand burial conditions. P. villosa fixed sand dunes through the distribution of the population at the top of the dune and the vertical relationship between the direction of windblown sand and the direction of growth of P. villosa, which stopped the expansion of the dune.ConclusionsGrowth characteristics of wind and drought tolerant leaf traits and adventitious roots under sand burial indicate that P. villosa is well adapted to dry sandy desert conditions and burial by sand. The distribution of the P. villosa population on the sand dune is a “brake” on its expansion. These findings provide new insight for active sand dune fixation and desertification control using native grass in the desertified regions.

Cosmogenic 10Be‐ and 21Ne‐based model exposure ages of desert pavements in the Thar Desert, India

AbstractThe Thar Desert, India has desert pavements comprising angular‐subangular to well‐rounded gravels at marginally higher elevations than the surrounding terrain. Sedimentological and geomorphic analyses suggest that the pavements are lags of weathered Mesozoic and older bedrock. The presence of Palaeolithic artefacts on the pavement surfaces and occasionally within their matrix was used to infer their antiquity and landscape stability.This study presents the first surface exposure ages based on cosmic‐ray‐produced 10Be and 21Ne for pavements at four sites in the Thar Desert, viz. Bhojka, Hamira, Solanki and Jayal. The computation of model exposure ages assumed that (a) the gravels were derived from cemented conglomerates, uplifted by tectonics and thereafter disintegrated by climate, and (b) cosmogenic nuclide production in the gravels began when the conglomerates approached the surface and, continued during their disintegration, gravity sliding of individual gravels and storage, until the present. Assuming an average burial depth of 50 cm, 21Ne and 10Be data provide ages ranging from 1.30 to 2.92 Ma and 1.11 to 5.4 Ma, respectively, for the two nuclides.Published electron spin resonance ages of Thar calcretes suggest the presence of water and extreme seasonality since 1.54 Ma. Such conditions facilitated the mobilization and precipitation of carbonates. The pavement ages and the minimum age of the conglomerate at 2.51 Ma extend the time of such desertic conditions to &gt; 2.51 Ma and suggest that the initiation of desertic conditions in the Thar was possibly linked to global aridity beginning around 3.6 Ma.Depending on assumptions, cosmic ray surface exposure (10Be) ages at Jayal range between 0.76 and 2.43 Ma. In the context of the Indian Palaeolithic, the presence of tools on the gravel surfaces and within dunes, suggests frequent occupation of this region from at least 0.76 Ma and, parallels Early to Middle Pleistocene Acheulian assemblages from Southern India.

The complex chemical effects of air pollutants, meteorology and dust on the concentrations of criteria and non-criteria air pollution in Kuwait

Air pollution is the leading environmental health risk factor globally. A number of cities experienced improvements in air quality during the COVID-19 lockdown; however such changes depend on the contributions from natural and anthropogenic sources and meteorological factors pertaining to each city. This study investigated the effects of anthropogenic and meteorological factors on air quality in Kuwait during the COVID-19 lockdown (22 March–10 May 2020) using mixed-effect regression and machine learning models. Criteria (PM2.5, PM10, NO2, O3, SO2, CO) and non-criteria (C6H6, NH3, H2S, NMHC) air pollutants were compared between the lockdown period, and the same period in the preceding and the following years, 2019 and 2021, respectively. The results showed that during the lockdown three criteria air pollutants (PM2.5, NO2, CO) were reduced by 38, 40, 26%, respectively. All no-criteria air pollutants were reduced, except for H2S. The arid region’s harsh desert conditions have major contributions to particulate pollution. Although PM levels are overwhelmed by meteorological and natural dust, stringent abatement measures on oil/gas hydrocarbon and power plant emissions can significantly reduce PM and other pollutants. Abatement measures on traffic pollution can further reduce the NO2 levels. This study highlights Kuwait's ongoing struggle with elevated levels of particulate and gaseous pollution, driven by hydrocarbon emissions and dust. Effectively tackling air quality requires a nuanced understanding of the interplay between air pollutants, meteorological, and dust covariates.

Morphological and Germination Characteristics of Alhagi maurorum Boiss. and Salsola richteri Kar. Seeds Distributed in the Karakum Desert of Turkmenistan

The Karakum Desert is the largest desert in Turkmenistan and covers a significant part of Central Asia. This desert is home to plant species that can adapt to hot, dry, and barren conditions. During the summer months, the Karakum Desert can get extremely hot, with temperatures reaching up to 50 °C, while in winter, it can drop to -20 °C. Therefore, the desert conditions significant seasonal temperature differences. In winter, rainfall is very low, snow rarely falls, and quickly melts. Afghan winds have an impact on the desert vegetation. The desert vegetation mainly consists of short grasses and woody shrubs. Despite the scarcity of rainfall and high temperatures during the summer months, steppe plants have generally been able to adapt to the harsh conditions of the desert. There are also species that have adapted to the desert climate, such as Alhagi maurorum Boiss., Haloxylon persicum Bunge, Haloxylon aphyllum (Minkw.) Iljin), Solanum nigrum L., and Salsola richteri Kar. These plants are highly valuable in terms of nutrition for animals and are used as winter animal feed in rural areas. In this study, the seed and germination characteristics of Alhagi maurorum Boiss. and Salsola richteri Kar, which are tree and shrub-like plants that can adapt to Karakum Desert conditions, were examined. In laboratory study, the morphological characteristics of the seeds were determined, and vitality and germination tests were conducted. Information was obtained about the germination adaptation of these plants in desert ecosystems. As a result of the study, it was determined that S. richteri had a very low rate of viable seeds and no germination, while the germination process of Alhagi maurorum could take a considerably long time.

Effects of Microbiota on the Soiling Process of PV Modules in Arid Zones of the Atacama Desert

Photovoltaic technology has proven to be a reliable, economical, and clean energy source that is capable of adapting to diverse geographical conditions. However, factors such as soiling overshadow these qualities, thus leading to production losses and affecting the profitability of this technology. For these reasons, soiling is a highly studied topic, which involves considering the physicochemical characterization of the deposited material, mitigation strategies, effect predictions, and cleaning mechanisms. However, there is a relatively unexplored area related to the microbiological contribution to soiling. The surface of photovoltaic modules, along with the deposited material and local atmospheric factors, fosters favorable conditions for the colonization of microorganisms. These microorganisms influence the soiling mechanisms and optical properties of photovoltaic modules. This work presents a detailed characterization of the microbial diversity present in the soiling deposited on photovoltaic modules installed in the Atacama Desert. Two study sites were defined: Antofagasta and the Solar Platform of the Atacama Desert, which have warm and cold desert climates, respectively. Mineralogical characterization tests, heavy metal analyses, TOC, and inorganic element analyses were conducted on the deposited material. Additionally, the culturable isolates and the metagenomic DNA of the soiling samples and biofilms grown on standard PV glass were characterized using next-generation sequencing. The results show that the deposited soiling contained a microbiological component that had adapted to extreme desert conditions. The presence of the genera Arthrobacter, Kocuria, and Dietzia were identified in the culturable isolates from Antofagasta, while Arthrobacter and Dietzia were obtained from the Solar Platform of the Atacama Desert. The metagenomic DNA was mainly represented by the genera Pontibacter, Noviherbaspirillum, Massilia, Arthrobacter, Hymenobacter, and Deinococcus at Antofagasta. However, at the Solar Platform of the Atacama Desert, the analyzed samples presented DNA concentrations below 0.5 ng/µL, which made their preparation unviable. At the PSDA, the biofilms formed by the genera Peribacillus and Kocuria were identified, whereas the UA showed a greater abundance of bacteria that favored biofilm formation, including those that belonged to the genera Bacillus, Sporosarcina, Bhargavaea, Mesaobacillus, Cytobacillus, Caldakalibacillus, and Planococcus. Based on these results, we propose a soiling mechanism that considers the microbiological contribution to material cementation.

Long-term performance analysis of a large-scale photoVoltaic plant in extreme desert conditions

Long-term performance analysis of a large-scale photoVoltaic plant in extreme desert conditions