Coastal Desert Research Articles

The Vestfold Hills are alive: characterising microbial and environmental dynamics in Old Wallow, eastern Antarctica.

Old Wallow is an underexplored, hyper-arid coastal desert in Antarctica's Vestfold Hills. Situated near an elephant seal wallow, we examined how stochastic nutrient inputs from the seal wallow affect soil communities amid environmental changes along a spatially explicit sampling transect. We hypothesized that nutrient levels would be elevated due to proximity to the seal wallow, influencing community distributions. While the soil bacterial and eukaryotic communities at the phylum level were similar to other terrestrial environments, analysis at class and family levels revealed a dominance of unclassified taxa that are often linked to marine environments. Elevated nutrient concentrations (NO3 -, SO4 2-, SO3) were found at Old Wallow, with conductivity and Cl- levels up to 10-fold higher at the lowest elevation soils, correlating with significantly (p < 0.05) higher abundances of halophilic (Halomonadaceace) and uncultivated lineages (Ca Actinomarinales, unclassified Bacillariophyta and unclassified Opisthonkonta). An improved Gradient Forest model was used to quantify microbial responses to 26 soil gradients at OW, revealing variable responses to environmental predictors and identifying critical environmental thresholds or drivers of community turnover. Major tipping points were projected for eukaryotes with SO4 2-, pH, and SO3, and for bacteria with moisture, Na2O, and Cl-. Thus, the Old Wallow ecosystem is primarily shaped by salt, sulphate, and moisture and is dominated by uncultivated taxa, which may be sensitive to environmental changes once critical tipping points are reached. This study provides critical baseline data for future regional monitoring under threats of environmental change.

Palynological characterization of a diverse desertic ecosystem: the Peruvian Lomas

The Pacific coastal Peruvian landscapes are dominated by desert and dry-forest biomes, which have undergone shifts in extent and floral composition in response to Plio–Pleistocene climatic fluctuations. Within this context, the coastal Lomas develop as seasonal vegetation patches, renowned for their high endemism, rich floral diversity, and essential ecosystem services. Despite growing within the desert biome, the Lomas exhibit characteristic elements and vegetation structure typical of a dry-forest biome, evidencing an active species migration between xeric biomes. However, assessing the historical evolution of this arid flora and, by extension, the coastal desert landscape, presents challenges. The scarcity of continental sedimentary records and a lack of extended and well-described palynological references impede these efforts. In response to this, our study offers a thorough morphological review of the Lomas palynoflora, encompassing over 194 genera from 76 families, representing approximately 80% of the known Lomas flora. Our review includes at least one species per reviewed genus, featuring 37 palynomorphs from endemic species (18.5% of the studied flora). This palynological characterization is intended to serve as accessible reference material for investigating the historical and long-term evolution of the coastal dry flora. Furthermore, these findings facilitate the analysis of honeys and bee floral foraging patterns, as well as the study of animal–plant or human–plant interactions from middens and archaeological remains.

Characterization and Agronomic Evaluation of 25 Accessions of Chenopodium quinoa in the Peruvian Coastal Desert

Quinoa is a healthy food that possesses high levels of protein that is enriched for dietary essential amino acids. The crop is highly diverse and well-adapted to changing climatic conditions. In spite of being vulnerable to pests and diseases, the development of new resistant varieties is possible. Taking advantage of this genetic variability is crucial for breeding programs, especially to adapt quinoa to the shifting needs of producers. In this study, 25 Peruvian accessions and two commercial varieties were characterized and agronomically evaluated in the Peruvian Pacific desert. Specific methodologies and descriptors of existing crops were used, analyzing a total of 24 quantitative and 23 qualitative variables with 15 repetitions per accession. The data were processed using descriptive statistics and a multivariate analysis. The results showed a high variability in morphological characteristics, with an area under the disease progress curve (AUDPC) of the presence of mildew between 529 and 1725, highlighting ACC06 with a lower severity of mildew. The percentage of saponins varied between 0.04 and 0.21 percent, with ACC06 being the one with the lowest percentage. Regarding the crop yield, it ranged between 0.35 and 8.80 t ha−1, highlighting the high-yielding accessions ACC55 and ACC14. These results were promising for the improvement of quinoa yield in the production conditions of the Peruvian Pacific desert.

Salicornia seed oil: A high-yielding and sustainable halophytic feedstock for biodiesel and energy in underutilized hypersaline coastal deserts

Addressing the critical need for sustainable biofuel sources that do not compete with prime agricultural land, this work presents a promising evaluation of Salicornia species as novel biodiesel feedstocks cultivable in underutilized coastal hypersaline regions. The research leveraged a successful pilot plant application, demonstrating the practical large-scale cultivation of Salicornia as an energy feedstock in these environments. Through innovative integration of advanced analytical techniques and multivariate statistical approaches, S. bigelovii and S. sinus-persica were comprehensively analyzed for their biodiesel potential. S. bigelovii seeds exhibited superior oil content (20.6 wt%) compared to S. sinus-persica (11.6 wt%), with an exceptional oil yield potential of 11,442 kg/ha, surpassing established biodiesel feedstocks. Oil extraction experiments also showed that cleaned high-density S. bigelovii seeds yielded up to 36.0 % oil content. Fatty acid methyl ester (FAME) profiling and biodiesel properties confirmed that both species meet ASTM D6751 and EN 14214 standards. The multivariate analyses revealed interesting relationships between Salicornia oils and other feedstocks, providing valuable insights for future breeding programs. Furthermore, advanced imaging elucidated Salicornia seed microstructures and oil distribution. This research establishes a robust analytical framework for evaluating novel biodiesel sources with significant implications for sustainable energy production in marginal lands. The findings pave the way for developing high-yielding, salt-tolerant energy crops, enhancing biodiesel feedstock cultivation in salt-affected coastal areas worldwide. By tackling both energy security and land use challenges in a changing climate, the study marks a breakthrough in sustainable biodiesel research.

Study on the Catalytic Activity and Selectivity of Manganese Dioxide-Modified Nickel–Iron-Based Hydroxide Electrodes for Initiating the Oxygen Evolution Reaction in Natural Seawater

Transition metal oxides, particularly NiFe(OH)2, are recognized for their high oxygen evolution reaction (OER) activity and structural stability. However, their performance in natural seawater electrolysis remains insufficiently studied. Manganese dioxide (MnO2), which is known for its multiple crystal phases and high OER selectivity, can be incorporated to enhance the catalytic properties. In this study, the OER catalytic performance of carbon cloth-supported manganese dioxide-modified nickel–iron bimetallic hydroxide (MnO2-NiFe-LDH/CC) electrodes was explored in both alkaline and natural seawater. Electrochemical tests demonstrated that the MnO2-NiFe-LDH/CC electrode achieved overpotentials of 284 mV and 363 mV at current densities of 10 mA·cm−2 and 100 mA·cm−2, respectively, with a Tafel slope of 68.6 mV·dec−1 in alkaline seawater. Most importantly, the prepared MnO2-NiFe-LDH/CC electrode maintained stable OER performance over 120 h of testing. In natural seawater, the MnO2-NiFe-LDH/CC electrode outperformed the NiFe-LDH/CC electrode by exhibiting an oxygen evolution selectivity of 61.1%. This study highlights the potential of MnO2-modified nickel–iron-based materials for efficient and stable OER in seawater electrolysis, which offers a promising approach for sustainable hydrogen production in coastal desert regions.

Natural History of the Genus Elasmoderus Saussure, 1888 (Orthoptera: Tristiridae), an Endemic and Eremic Element of the Transitional Coastal Desert of Chile.

The genus Elasmoderus belongs to the family Tristiridae, an orthopteran group that is distributed across the transitional region of South America and represented in the Andean areas of Peru, Argentina, and Chile. The species of Elasmoderus have morphological adaptations that make them especially suited for surviving in extreme arid environments and are an endemic and eremic group of the north-central region of Chile. On the basis of field samplings, direct observations, and a comprehensive literature review, we collected information about the genus Elasmoderus. The objectives of this research were: (i) to provide updated information on the geographical distribution range of the species of the genus Elasmoderus, and (ii) to collect and synthesize the most relevant information on the natural history and ecology of this orthopteran group as a basis for future long-term studies of its populations. Although this genus is underrepresented compared to other orthopteran families, it has developed interesting adaptations to extreme arid environments that remain unstudied to this date. E. lutescens is known to be one of the species with a wider latitudinal distribution, mostly on the coast and longitudinal valley of Atacama. E. minutus has a more restricted distribution, whereas E. wagenknechti is concentrated in coastal and interior environments of the Coquimbo region, an area where it reaches high population densities, thus affecting crops and natural vegetation and polluting water sources. Our findings underscore the importance of conducting comprehensive research on native insect groups that are poorly known but crucial for arid and semiarid ecosystems. These data will serve as a starting point for conducting long-term studies on this orthopteran group to gain a better understanding of the importance and role of these species in the semiarid ecosystems of northern Chile.

The hidden oases: unveiling trophic dynamics in Namib's fog plant ecosystem

The Namib Desert is a hyperarid coastal desert where fog is a major moisture source. We hypothesized that the fog-harvesting grass Stipagrostis sabulicola establishes an important ecological niche, termed the "Fog-Plant-Oases" (FPOs), and serves as the primary carbon source for the invertebrate community. To determine this, we measured the natural variations of the stable carbon and nitrogen isotopes (δ13C and δ15N) of invertebrates as well as that of plant biomass and belowground detritus and estimated the contributions of the fog plants in their diets. Our findings revealed a complex trophic structure and demonstrated that S. sabulicola fuels carbon flow from lower to higher trophic levels in the aboveground food web. The distinct δ13C values of bacterial- and fungal-feeding nematodes indicated however the separation of the aboveground niche, which is primarily sustained by S. sabulicola, from the belowground niche, where wind-blown sediments may serve as the main energy source for the soil biota. Our findings further accentuate the critical role of S. sabulicola FPOs in establishing complex trophic dynamics and a distinctive food web within the hyperarid Namib dunes.

Changes of Hematology Profile, Blood Biochemistry and Hormonal Functions of Dromedary She-Camels under the Northwest Coastal Desert in Egypt

Changes of Hematology Profile, Blood Biochemistry and Hormonal Functions of Dromedary She-Camels under the Northwest Coastal Desert in Egypt

Extreme High-Elevation Mammal Surveys Reveal Unexpectedly High Upper Range Limits of Andean Mice.

AbstractIn the world's highest mountain ranges, uncertainty about the upper elevational range limits of alpine animals represents a critical knowledge gap regarding the environmental limits of life and presents a problem for detecting range shifts in response to climate change. Here we report results of mountaineering mammal surveys in the Central Andes, which led to the discovery of multiple species of mice living at extreme elevations that far surpass previously assumed range limits for mammals. We livetrapped small mammals from ecologically diverse sites spanning >6,700 m of vertical relief, from the desert coast of northern Chile to the summits of the highest volcanoes in the Andes. We used molecular sequence data and whole-genome sequence data to confirm the identities of species that represent new elevational records and to test hypotheses regarding species limits. These discoveries contribute to a new appreciation of the environmental limits of vertebrate life.

Halophytic Bacterial Endophyte Microbiome from Coastal Desert-Adapted Wild Poaceae Alleviates Salinity Stress in the Common Wheat Triticum aestivum L.

Abiotic stresses threaten the strategic crops of Poaceae (Gramineae) worldwide. Habitat-adapted microbiome of wild plants has the potential to alleviate abiotic stresses in alternate hosts. Persian Gulf's coastal deserts are colonized by halophyte plants hosting habitat-adapted halophytic microbiota. Here, endophytic bacteria from wild Poaceae in coastal deserts of the north Persian Gulf at Hormozgan province, Iran, were isolated and screened for mitigating salinity stress in wheat. Accordingly, seven dominant species of wild Poaceae in the region, i.e., Aeloropus lagopoides, Aeloropus litiralis, Chrysopogon aucheri, Cymbopogon olivieri, Desmostachya sp., Halopayrum mucronatum, and Sporbuls arabicus, were explored. In total, 367 endophytic bacteria were isolated, 90 of which tolerated 2.5-M NaCl. Of these, 38 strains were selected based on their bioactivity and applied for in vitro wheat-interaction assays under 250-mM NaCl stress. Five superior strains promoted seed germination and growth indices in rain-fed winter wheat cv. Sardari, i.e., Bacillus subtilis B14, B19, & B27, Bacillus sp. B21, and Bacillus licheniformis Ba38. In planta assays in saline soil (2.7 dS m-1) using the superior strains indicated that Bacillus sp. B21 and Bacillus licheniformis Ba38 increased germination and root and shoot lengths and their dry and fresh weights in wheat seedlings. Moreover, phenolics and flavonoids contents of wheat seedlingswere influenced by endophyte application. Thus, the coastal desert-adapted microbiome of wild Poaceae could alleviate abiotic stress and promote growth in cultivated species of Poaceae, such as wheat.

Paleoclimatic reconstruction of the Late Pleistocene Talara Tar Seeps, Peru, using fossil reptiles, small mammals, and birds

Functional traits of vertebrates can be used to infer paleoenvironmental conditions, allowing research into past climate changes and biotic responses. Birds are generally considered poor palaeoclimatic proxies due to their high vagility. Here, we analyze biogeographical and climatic niche information from multiple vertebrate groups including small mammals, reptiles, and birds to infer the paleoclimatic conditions present during the Late Pleistocene (∼14,500–17,000 years BP) at Talara, an asphaltic paleontological locality on the northern Peruvian coast. We created Ecological Niche Models for the nearest living relative of each fossil species identified at Talara. We then used the Mutual Ecogeographic Range method, obtaining the overlapping area between distributions for each vertebrate group (birds, reptiles, and small mammals) as well as for combinations of groups, to infer the paleoclimate at Talara and to determinate what taxonomic groups are best for reconstructing climate in this system. Our analyses indicate that conditions at Talara were slightly cooler and significantly wetter than those of the present day. Individually, different vertebrate groups provide different paleoclimatic information. Birds were found to be a poor paleoclimatic proxy. Mammals were good for inferring paleoprecipitation but not paleotemperature. Reptiles were good group for inferring paleotemperature but not paleoprecipitation. While analyzing all vertebrate groups together yields the most robust conclusions, reptiles and small mammals combined are a good proxy for inferring both paleoprecipitation and paleotemperature. Our results suggest an interstadial period that agrees with paleotemperatures inferred from isotopic and sedimentary information. Our research indicates that today, the southern portion of the Cauca biogeographic province (230 km NE from Talara) has comparable climatic conditions to Late Pleistocene Talara. Understanding how the Talara region transitioned from this biodiverse ecosystem to the hyperarid coastal desert of today could have important implications for predicting biotic response and tipping points in the context of modern climate change.

Fog water traps as a low-cost alternative source of water in coastal desert areas of the Pacific

Water scarcity is the most common concept associated with the desert. The Atacama Desert is worldly known as the aridest desert on Earth. However, some populations are established in this area, requiring water for living that promotes the search of alternative water sources, as fog catchers taking in advance the regional fog event known as Camanchaca. During 2015, the construction of fog trap units was carried out on a hill in the Falda Verde sector in Chañaral (North Chile). In the design of these new fog trap units it was considered to improve the anchoring system and the distribution and angles of the clamping tensioners in order that the structure could withstand the maximum wind speeds that have been registered in the area, while recording the water accumulated by these units during a period of 12 months determined an average catchment of 22 liters of water/m2 per month.

Late pre-Hispanic fog oasis settlements and long-term human occupation on the Peruvian central coast from satellite imagery

Fog oases (lomas) present pockets of verdant vegetation within the arid coastal desert of Andean South America and archaeological excavation within some of the oases has revealed a long history of human exploitation of these landscapes. Yet lomas settlements are under-represented in archaeological datasets due to their tendency to be located in remote inter-valley areas. Here, the authors employ satellite imagery survey to map the locations of anthropogenic surface features along the central Peruvian coast. They observe two categories of archaeological features, large corrals and clustered structures, and document a concentration of settlement features within lomas landscapes that suggests a pre-Hispanic preference for both short- and long-term occupation of these verdant oases.

Stacked machine learning models for predicting species richness and endemism for Mediterranean endemic plants in the Mareotis subsector in Egypt

An effective method for identifying species and evaluating the effects of changes caused by humans on specific species is the application of species distribution modelling (SDM) in desert environments. The fact that many dry lands and deserts throughout the world are situated in inhospitable regions may be the reason why such applications are still infrequently used on plant species in Egypt's Mediterranean region. Henceforth, the current study aims to map species richness and weighted endemism of Mediterranean endemics in the Mareotis subsector in Egypt and determine the environmental variables influencing distribution of these taxa. We produced a map of species distribution range using Ensemble SDMs. Further, stacked machine learning ensemble models derived from Random Forest (RF) and MaxEnt models were applied on 382 Mediterranean endemics distribution data to estimate and map diversity and endemism using two indices: species richness (SR) and weighted endemism index (WEI). The best models for ensemble modelling were chosen based on Kappa values and the Area Under the Receiver Operator Curve (AUC). The results showed that the models had a good predictive ability (Area Under the Curve (AUC) for all SDMs was > 0.75), indicating high accuracy in forecasting the potential geographic distribution of Mediterranean endemics. The main bioclimatic variables that impacted potential distributions of most species were wind speed, elevation and minimum temperature of coldest month. According to our models, six hotspots were determined for Mediterranean endemics in the present study. The highest species richness was recorded in Sallum, Matrouh wadis and Omayed, followed by Burg El-Arab, Ras El-Hekma and Lake Mariut. Indeed, species richness and endemism hotspots are promising areas for conservation planning. This study can help shape policy and mitigation efforts to protect and preserve Mediterranean endemics in the coastal desert of Egypt. These hotspots should be focused on by policy makers and stakeholders and declared as protectorates in the region. The largest number of species per area would be protected by focusing primarily on the hotspots with high species richness.

Tracking kelp-type seaweed fuel in the archaeological record through Raman spectroscopy of charred particles: examples from the Atacama Desert coast

Tracking kelp-type seaweed fuel in the archaeological record through Raman spectroscopy of charred particles: examples from the Atacama Desert coast

Paposo and the Genealogy of the Changos in the Atacama Desert Coast

There is some degree of inaccuracy around the ethnic and kinship categories frequently assigned (eighteenth to nineteenth centuries) to Paposo colonial local groups on the Atacama Desert coast (25°S). Furthermore, the data referring to colonial Paposo does not give a clear insight into the number of settlements that formed it, its exact geographical location, and its occupational frequencies due to how inaccessible this Chango indigenous enclave was to the Spanish crown. This problem has been analyzed with a documented genealogy of the native coastal families and a review of Atacama's Estancia and mining colonization paradigms.

Violence in fishing, hunting, and gathering societies of the Atacama Desert coast: A long-term perspective (10,000 BP-AD 1450).

In this study, we examine the long-term trajectory of violence in societies that inhabited the coast of the Atacama Desert in northern Chile using three lines of evidence: bioarchaeology, geoarchaeology and socio-cultural contexts (rock art, weapons, and settlement patterns). These millennia-old populations adopted a way of life, which they maintained for 10,000 years, based on fishing, hunting, and maritime gathering, complementing this with terrestrial resources. We analyzed 288 adult individuals to search for traumas resulting from interpersonal violence and used strontium isotopes 87Sr/86Sr as a proxy to evaluate whether individuals that showed traces of violence were members of local or non-local groups. Moreover, we evaluated settlement patterns, rock art, and weapons. The results show that the violence was invariant during the 10,000 years in which these groups lived without contact with the western world. During the Formative Period (1000 BC-AD 500), however, the type of violence changed, with a substantial increase in lethality. Finally, during the Late Intermediate Period (AD 1000-1450), violence and lethality remained similar to that of the Formative Period. The chemical signal of Sr shows a low frequency of individuals who were coastal outsiders, suggesting that violence occurred between local groups. Moreover, the presence of weapons and rock art depicting scenes of combat supports the notion that these groups engaged in violence. By contrast, the settlement pattern shows no defensive features. We consider that the absence of centralized political systems could have been a causal factor in explaining violence, together with the fact that these populations were organized in small-scale grouping. Another factor may have been competition for the same resources in the extreme environments of the Atacama Desert. Finally, from the Formative Period onward, we cannot rule out a certain level of conflict between fishers and their close neighbors, the horticulturalists.

Fog water traps as a low-cost alternative source of wáter in coastal desert areas of the Pacific

Fog water traps as a low-cost alternative source of wáter in coastal desert areas of the Pacific

Greening and Browning Trends on the Pacific Slope of Peru and Northern Chile

Accurate detection and quantification of regional vegetation trends are essential for understanding the dynamics of landscape ecology and vegetation distribution. We applied a comprehensive trend analysis to satellite data to describe geospatial changes in vegetation along the Pacific slope of Peru and northern Chile, from sea level to the continental divide, a region characterised by biologically unique and highly sensitive arid and semi-arid environments. Our statistical analyses show broad regional patterns of positive trends in EVI, called “greening”, alongside patterns of “browning”, where trends are negative between 2000 and 2020. The coastal plain and foothills, up 1000 m, contain notable greening of the coastal Lomas and newly irrigated agricultural lands occurring alongside browning trends related to changes in land use practices and urban development. Strikingly, the precordilleras show a distinct ‘greening strip’, which extends from approximately 6°S to 22°S, with an altitudinal trend, ascending from the tropical lowlands (170–780 m) in northern Peru to the subtropics (1000–2800 m) in central Peru and temperate zone (2600–4300 m) in southern Peru and northern Chile. We find that the geographical characteristics of the greening strip do not match climate zones previously established by Köppen and Geiger. Greening and browning trends in the coastal deserts and the high Andes lie within well defined climatic and life zones, producing variable but identifiable trends. However, the distinct Pacific slope greening presents an unexpected distribution with respect to the regional Köppen–Geiger climate and life zones. This work provides insights on understanding the effects of climate change on Peru’s diverse ecosystems in highly sensitive, biologically unique arid and semi-arid environments on the Pacific slope.

Rhizobacterial Isolates from Prosopis limensis Promote the Growth of Raphanus sativus L. Under Salt Stress

Microbial biotechnology employes techniques that rely based on the natural interactions that occur in ecosystems. Bacteria, including rhizobacteria, play an important role in plant growth, providing agricultural crops with an alternative that can mitigate the negative effects of abiotic stress, such as those caused by saline environments. In this study, bacterial isolates were obtained from soil and roots of Prosopis limensis Bentham from the department of Lambayeque, Peru. This region has high salinity levels, therefore, the collected samples were used to isolate plant growth-promoting rhizobacteria (PGPR), which were identified through morphological, and physical-biochemical characteristics. These salt tolerant bacteria were screened phosphate solubilization, indole acetic acid, deaminase activity and molecular characterization by 16S rDNA sequencing. Eighteen samples from saline soils of the Prosopis limensis plants in the northern coastal desert of San Jose district, Lambayeque, Peru. The bacterial isolates were screened for salt tolerance ranging from 2 to 10%, a total of 78 isolates were found. Isolates 03, 13 and 31 showed maximum salt tolerance at 10%, in vitro ACC production, phosphate solubilization and IAA production. The three isolates were identified by sequencing the amplified 16S rRNA gene and were found to be Pseudomonas sp. 03 (MW604823), Pseudomonas sp. 13 (MW604824) and Bordetella sp. 31 (MW604826). These microorganisms promoted the germination of radish plants and increased the germination rates for treatments T2, T3 and T4 by 129, 124 and 118% respectively. The beneficial effects of salt tolerant PGPR isolates isolated from saline environments can be new species, used to overcome the detrimental effects of salt stress on plants. The biochemical response and inoculation of the three isolates prove the potential of using these strains as a source of products that can be employed for the development of new compounds proving their potential as biofertilizers for saline environments.