Ancient Desert Research Articles

Insights into the diversity and survival strategies of soil bacterial isolates from the Atacama Desert.

The Atacama Desert, the driest, with the highest radiation, and one of the most ancient deserts in the world, is a hostile environment for life. We have a collection of 74 unique bacterial isolates after cultivation and confirmation by 16S rRNA gene sequencing. Pigmentation, biofilm formation, antimicrobial production against Escherichia coli MG1655 and Staphylococcus aureus HG003, and antibiotic resistance were assessed on these isolates. We found that approximately a third of the colonies produced pigments, 80% of isolates formed biofilms, many isolates produce growth inhibiting activities against E. coli and/or S. aureus, and many were resistant to antibiotics. The functional characterization of these isolates gives us insight into the adaptive bacterial strategies in harsh environments and enables us to learn about their possible use in agriculture, healthcare, or biotechnology.

Novel cercozoan and heterolobosean protists from the rhizosphere and phyllosphere of two endemic cacti from the Atacama Desert

Cercozoans and heterolobose amoebae are found across terrestrial habitats where they feed on other unicellular microbes, including bacteria, fungi and microalgae. They constitute a significant fraction of soil ecosystems and are integral members of plant microbiota. Here, we present the results on the isolation of protozoans from the rhizosphere and phyllosphere of Browningia candelaris (Meyen) in the Andean Altiplano and Eulychnia taltalensis (F. Ritter) from the Coastal Cordillera of the Atacama Desert, both endemic to this ancient desert. We identified a new heterolobose amoeba species of the genus Allovahlkampfia isolated from cactus soil, three new species of the different glissomonad genera Allapsa, Neoheteromita, Neocercomonas and one new thecofilosean amoeba of the genus Rhogostoma isolated from the phyllosphere of one studied cactus. In addition, one bacterivorous flagellate was isolated from cactus spines and identified as a member of the non-scaled imbricatean family Spongomonadidae (Spongomonas). The isolation of protists from cactus spines extends the knowledge on the habitat ranges of taxa typically found on plant leaves or soils. The molecular data presented here is a prerequisite for further investigations on the ecology and diversity of protists including next-generation sequencing of microhabitats in plants and the rhizosphere, allowing for deeper taxonomic classification.

Quantitative reconstruction of Early Cretaceous dune morphology in the Ordos paleo-desert and its paleoclimatic implications

Deserts are among the most important terrestrial sedimentary environments and have existed in all periods throughout Earth’s history. In contrast to modern deserts, the ability to quantitatively evaluate the area and desertification degrees of ancient deserts is limited due to the lack of unambiguous proxies. Dune morphology and their spatial arrangements directly reflect the degree of desertification of deserts. Recently, a methodology for obtaining the morphological parameters of dunes was established, although it has not been applied to ancient dunes and deserts in deep time. In the Ordos Basin, both the Early Cretaceous desert and modern deserts (Hobq Desert and Mu Us Desert) were well developed and exposed, which makes the Ordos Basin an ideal place to quantitatively evaluate the paleo-desert based on the proposed methodology. In this study, a total of 698 and 1,490 morphological parameters reflecting the Early Cretaceous desert and modern deserts in the Ordos Basin were obtained, respectively. For the Ordos paleo-desert, our results show that its area was larger and its degree of desertification was more severe than those of modern mid-latitude deserts, including the modern desert in the Ordos Basin, but were similar to those of the modern low-latitude deserts. Our results, therefore, suggest that the Ordos paleo-desert was a non-negligible and large desert during an interval of Earth’s history. Since the other controlling factors, such as regional geography and sources of both the ancient and modern deserts in the Ordos Basin, have remained nearly unchanged, we speculate that it may have been the relatively high temperature, high levels of atmospheric carbon dioxide and relatively low precipitation during the greenhouse period (i.e., Early Cretaceous) that led to the large area and severe degree of desertification of the Ordos paleo-desert.

Lake dynamics in an Early Jurassic desert: Evidence from the Clarens Formation in southern Africa

ABSTRACTInterdune deposits are sensitive to climatic fluctuations and ancient interdune lacustrine systems can reveal the drivers of erg dynamics through time and space. This southern African study details the dynamics of interdune deposition in a vast ancient desert system that was active over Pangaea in the Middle Mesozoic and formed part of one of the largest known sand seas in Earth's history. Focusing on the Sinemurian to Pliensbachian Clarens Formation in the main Karoo Basin (south‐west Gondwana), three facies associations were identified that formed in meso‐scale and macro‐scale lakes amongst aeolian dunes and sand sheets of the Clarens erg system. The northern facies association is restricted to interdune hollows within an actively climbing dune system. High‐sediment availability and high‐wind speeds limited the space available for these meso‐scale lakes to expand. Here, migrating dunes outpaced the water table rise promoting the formation of discontinuous lenses of lake deposits, as is typical in erg centres. The southern facies associations developed both in spatially isolated meso‐scale lakes, where flooding was controlled by groundwater inundation (water table rise), as well as in macro‐scale lakes, where flooding was related to groundwater inundation and floods (surface runoff) that induced terminal splays. Relative to the north, the southern facies associations, with their more significant thickness and lateral extent, show that, here, the basin was characterized by a higher rate of relative subsidence. Moreover, the southern lake systems were established along the erg's margin, where the interdunes expanded during pluvial phases. Ultimately, the facies associations in the Clarens Formation show that the widespread arid conditions in the Early Jurassic of south‐west Gondwana were subjected to prolonged and repeated pluvial phases in an otherwise harsh environment. Given the prominence of Jurassic aeolianites across Pangea, this study provides a southern African perspective on global palaeo‐erg dynamics and Early Jurassic climatic shifts.

Lacertoid tracks from the Botucatu Formation (Lower Cretaceous) with different locomotor behaviors: A new trackmaker with novel paleoecological implications

The Botucatu Formation (Paraná Basin) is an eolian deposit that represents an extensive paleoerg that existed in the south-central Gondwana during the Early Cretaceous. The fossil record of the unit is almost exclusively constituted of ichnofossils, including numerous tracks and burrows of vertebrates and invertebrates. The greatest trace fossil diversity of the Botucatu Formation is reported at the Ouro ichnosite, located in the Araraquara municipality region, São Paulo State, Brazil. This site comprises a faunal-rich setting of greater humidity in the ancient desert. In this work, a new footprint morphotype is reported for the Ouro ichnosite. Five trackways including tracks with an elongated anteroposterior axis associated with tail drag marks are described. The morphology of the autopodia and geometry of the trackways indicate an affinity with a lizard-like trackmaker. Furthermore, at least three different modes of locomotion were recognized: a typical walking gait, a pause-walking gait, and sideways drifting. The current report suggests Lepidosauria may have inhabited the ancient Botucatu desert, a group never reported before in this geological context. This finding expands the knowledge about the Botucatu Formation paleofauna and adds more complexity to its ecological network. Squamata and Sphenodontia are plausible candidates to have produced the described fossil tracks.

Relict olive trees at runoff agriculture remains in Wadi Zetan, Negev Desert, Israel

Olive (Olea europaea) trees in the arid Negev Desert of southern Israel are important relicts on the ancient agricultural landscape. Among them are a cluster of several trees located in Wadi Zetan, at the heart of the Shivta horticulture terroir, with its abundant agricultural runoff remains. Two isolated olive bearing trees stand in a sheltered beneath cliff in the upper part of the wadi. Radiocarbon dating of an internal part of the trunk of one of these living trees estimates its minimum age as the mid-16th – early 17th century CE (∼500 years old). Archaeological excavations conducted beneath the trees and the adjacent dam revealed OSL samples of loess accumulation dated to the Early Islamic period (8th-9th centuries CE). The stratigraphy and chronology of this sediment deposition indicate its rapid and short accumulation. Palynological analysis of the same OSL dated samples indicates that grapevines and olive trees were cultivated in the immediate vicinity of the site during the Early Islamic period. The lack of pollen of cultivated taxa from the latter part of the sequence points to cessation of the agricultural activity, probably a few hundred years later. Leaf samples for DNA profiling of the trees in comparison to other local old olive trees around the country, indicate that the trees in Wadi Zetan are genetically close to a known cultivar common among ancient olive trees. The trees have survived for at least a few hundred years, in an arid area, due to the local conditions and enhanced drainage from the man-made upper runoff system. These old olive trees bear a powerful and symbolic significance, indicating the endurance and sustainability of ancient desert runoff agriculture. Moreover, the survival of their relicts in Wadi Zetan suggests their potential as cultivars greater resilience to the harsh growing conditions of arid environments.

Effect of dung, ash and runoff water on wheat and barley grain sizes and stable isotope ratios: Experimental studies in ancient desert agriculture (Negev, Israel)

Archaeological excavations in the central Negev desert in terraced wadi fields at Horvat Haluqim revealed remains of two ancient fertilizers: charred plant ash and animal dung. Average annual rainfall in the area is 94 mm. Runoff rainwater from natural hillside catchments, captured by terrace walls, augmented soil moisture in valleys to enable agriculture. Some terraced fields are farmed by Bedouin, who grow wheat and barley. Using these cereal varieties, we conducted novel investigations in this arid desert environment about the effect of plant ash, sheep dung and runoff water on grain sizes, δ13C, Δ13C, and δ15N. Our study included both controlled pot experiments and traditional runoff farming by Bedouin. The pots were filled with local desert loess soil to investigate the effect of four different fertilizer treatments – (1) “None” for baseline data, (2) “Ash”, (3) “Dung”, (4) “Ash & Dung combined” – on the above cereal varieties. The largest cereal grains were produced by treatment 4 (ash & dung), which is a remarkable result, because it independently corroborates the archaeological findings. The pots received equal amounts of tap water, totalling 240 mm for barley and 325 mm for wheat. The Δ13C values of cereal grains in the pot experiments ranged from 15.62 to 17.47‰. Concerning δ15N, sheep dung produced a small increase, as compared to the baseline data, but plant ash fertilizer caused a decrease. Ash and dung together (treatment 4) yielded variable δ15N results. Stable isotopes of the same cereal varieties were also studied in the context of traditional runoff farming by Bedouin in terraced wadi fields in the area. Runoff water reception by terraced fields is by nature highly variable. A negative correlation was found between δ13C of cereal grains and runoff soil moisture. The Δ13C values ranged from 12.59 to 17.44‰. Concerning δ15N, cereal grains from the drier fields had comparatively high values, while the wetter fields yielded the two lowest δ15N values. Nevertheless, other δ15N values from wetter fields were quite high, indicating the effect of additional factors besides runoff water. Though the Bedouin do not add fertilizers to the terraced fields, their sheep and goats graze the cereal stubble after the harvest. This leads to a spatially random and spotty distribution of manure, which may explain the diverging δ15N values.

Stalled at Friendship Station: Under Ancient Desert Skies, the Socialist Silk Road, and Cinematic Collaboration on the Eve of the Sino‐Soviet Split

This article contributes to an emerging history of socialist world cinema by uncovering the forgotten story of a Sino‐Soviet cinematic collaboration from 1957–58: a film expedition that travelled the route of a proposed railway line linking Almaty in Kazakhstan, via Xinjiang, to Lanzhou in western China. At the height of the Sino‐Soviet “honeymoon” in the 1950s, this 2,800km “Road of Friendship” was celebrated as a revival of the ancient Silk Road for an age of industrialized, international socialism. Co‐produced by the Moscow and Shanghai scientific‐popular film studios, the film had two directors, the Soviet veteran Vladimir Shneiderov and the Chinese novice Qin Zhen. The film they created appeared under two names: while its Chinese title, Almaty‐Lanzhou (Alamutu‐Lanzhou), spoke in neutral tones of connection and modernization, the Russian title, Under Ancient Desert Skies (Pod nebom drevnikh pustyn'), evoked the exotic allure of a motor expedition along the traces of the Silk Road. My excavation of the Road of Friendship and the film that celebrated its construction offers a case study in the aspirations and limitations of Sino‐Soviet collaboration in the mid‐1950s. In particular, the history of both railway and film illuminate the role of Xinjiang as a frontier region where the ideals of internationalist collaboration confronted a longer history of imperial contestation between the Russian and Chinese states in Central Asia. Grounded in archival materials, this reconstruction of the project foregrounds both the politics and the poetics of collaboration: both the production history of the film, and the way that the film itself stages and performs its own ideals of collaborative “friendship.” Collaboration, it becomes clear from the film and its production materials, was both an important ideal and a fraught business. The Road of Friendship itself, meanwhile, fell victim to the Sino‐Soviet Split of the early 1960s. The two sides were supposed to connect at the town of Druzhba (Dostyk, “Friendship”) on the Sino‐Soviet border, but the Chinese branch only reached Druzhba in 1990—just in time for the collapse of the USSR. Today the Lanzhou—Almaty rail route constitutes a central link in China's Belt and Road infrastructure initiative, another reimagining of the Silk Road for twenty‐first‐century global capitalism.

Between Sand Dunes and Hamadas: Environmental Sustainability of the Thar Desert, West India

Extensive geographic areas of the world show a long-term atmospheric moisture deficit. Desertification of Rajasthan is concurrent with the strengthened weather extremality and mean annual air temperature (MAAT) rise over the western part of the Indian subcontinent. The present landscape aridification due to the precipitation decrease and reinforced windiness generates surface-cover dryness, aeolian erosion with a mass sediment transfer, salinity of excessively irrigated lands and groundwater depletion; altogether these pose major geo-environmental threats and settlement risks of the expanding Thar Desert. Livestock-overgrazing of sparse-vegetation contributes to ecological pressure to the fragile wasteland ecosystems with approximately three-quarters of the countryside affected to a certain extent by degradation and >50% exposed to wind erosion. Sand dune stabilisation by the drought-adapted tree plantation, the regional hydrology network regulation and the arid-land farming based on new xerophytic cultigens are the key land-use and mitigation strategies. Specific geomorphic palaeosettings predetermined patterned adaptive forms of the ancient desert inhabitation. Geo- and eco-tourism contributes to the arid-zone socioeconomic sustainability with regard to the rich natural and cultural heritage of the area. This study outlines the main effects of the current climate variations on the pristine and occupied lands of western Rajasthan, and the past and present relief transformations, and reviews the modern anthropogenic responses to desertification.

Diverse preserved dinosaur footprint assemblage from Jurassic–Cretaceous transition eolian dune deposits of western Shandong Province, China

Ancient desert, characterized by low biotic diversity as well as low preservation potential, has long been assumed as devoid of biotic activity. However, recent works from Mesozoic trace fossils preserved in the eolianites in North America, South America and East Asia indicate that the ancient desert can also have diverse inhabitants. This paper presents a diversified preserved dinosaur track assemblage from the Jurassic-Cretaceous transition eolian dune deposits in western Shandong Province, China. Based on the ichnological analysis, tracks are assigned to ichnogenus Anomoepus, Eubrontes-like and Ornithopodichnus-like forms, representing the oldest and second example of the Chelichnus ichnofacies reported from China as well as Asia. Sedimentological analysis of the tracksites indicates that tracks occurred in linear dunes under arid climatic conditions. Well-preserved tracks with detailed anatomical information are more likely to be preserved in moist sands, contrary to the dry cohesionless sands. Anomoepus and Ornithopodichnus-like tracks cooccurring with northwestward winds were made during summer wet season, while Eubrontes-like track was present during winter dry season characterized by strong northeastward wind, implying different habits between ornithopod and theropod dinosaurs. The preserved Jurassic-Cretaceous transition dinosaur tracks in eolian dune deposits not only expand the spatial-temporal distribution of dinosaur fauna in North China, but also greatly improve our understanding of the adaptive capacity of dinosaurs in severe living conditions, such as the desert environment.

Ecological wisdom, a social–ecological approach to environmental planning with an emphasis on water resources: the case of Qanat Hydraulic Structure (QHS) in a desert city of Iran

Improper exploitation of water resources has caused a water crisis and a challenge for water resource management around the world, especially in desert cities with vulnerable landscapes. Ecological wisdom is evident in the ancient desert cities of Iran, based on Qanat Hydraulic Structures (QHS). For long, QHS has been the main water transmission system from long-distance resources to cities in hot-arid regions. This study aimed to explore the ecological wisdom of ancient QHS and to empower it with the current social values, which may be applied as a rational normative approach to create balance between the landscape ecological integrity and development processes. We first investigated scientific databases to extract the principles of ecological wisdom and the theoretical framework. In the next stage, we conducted field studies to extract the social and ecological principles and rules, governing the workable pattern of structure and function of QHS in the desert city of Yazd, Iran, as a case study. Next, the comparative–deductive method was used for comparing the principles of ecological wisdom with the rules governing the corridor networks of QHS. Finally, we compared the compatibility of ecological wisdom principles governing QHS with the criteria and sub-criteria of landscape sustainability in Yazd. The results revealed that ecological wisdom can provide a framework to integrate the traditional knowledge of QHS in scientific ecological knowledge and social system of cities toward sustainable water resource planning and sustainable landscaping.

A new insect trackway from the Upper Jurassic-Lower Cretaceous eolian sandstones of São Paulo State, Brazil: implications for reconstructing desert paleoecology.

The new ichnospecies Paleohelcura araraquarensis isp. nov. is described from the Upper Jurassic-Lower Cretaceous Botucatu Formation of Brazil. This formation records a gigantic eolian sand sea (erg), formed under an arid climate in the south-central part of Gondwana. This trackway is composed of two track rows, whose internal width is less than one-quarter of the external width, with alternating to staggered series, consisting of three elliptical tracks that can vary from slightly elongated to tapered or circular. The trackways were found in yellowish/reddish sandstone in a quarry in the Araraquara municipality, São Paulo State. Comparisons with neoichnological studies and morphological inferences indicate that the producer of Paleohelcura araraquarensis isp. nov. was most likely a pterygote insect, and so could have fulfilled one of the ecological roles that different species of this group are capable of performing in dune deserts. The producer could have had a herbivorous or carnivorous diet or been part of the fauna of omnivores, being able to adopt herbivorous, carnivorous, and saprophagous diets when necessary. In modern dune deserts, some species of pterygote insects are detritivores (like Tenebrionidae), relying on organic matter that accumulated among the sand grains of the dunes during dry periods with no plant growth. The presence of additional burrows suggests that the Botucatu paleodesert would have had a detritivorous fauna like this. Based on the interpretation of the ichnofossil producers, it was possible to reconstruct the food web of this paleodesert. All the omnivorous and herbivorous invertebrates and the herbivorous ornithopod dinosaurs made up the primary consumers. These animals were, in turn, the food source for bigger carnivorous or omnivorous animals unable to feed on detritus, like arachnids, possible predatory insects, mammaliaforms, and theropod dinosaurs. The highest trophic level was occupied by larger theropod dinosaurs and mammaliaforms, which, because of their size, could prey upon a wide range of animals. The producer of Paleohelcura araraquarensis isp. nov. could have been a primary consumer if it were an omnivorous detritivore or a herbivore, or a secondary consumer if it were produced by a predatory insect or an omnivore relying on animal biomass. The description of this new trackway expands the knowledge on the faunal composition of the Botucatu paleodesert and provides insights into the ecological relationships in ancient deserts. The presence of these arthropod trackways in Mesozoic eolian deposits helps to trace a continuity between Paleozoic and post-Paleozoic desert ichnofaunas, further reinforcing a single Octopodichnus—Entradichnus Ichnofacies for eolian deposits.

A Case for Soul in the Desert Fathers According to Hillman’s Interpretation of Psyche in his Work A Blue Fire

A Case for Soul in the Desert Fathers According to Hillman’s Interpretation of Psyche in his Work A Blue Fire Nathan Garcia (bio) The psychologist James Hillman saw himself as a fierce advocate for the soul. His prolific career advanced the understanding that psychotherapy return to its mytho-poetic roots. Concomitant to these efforts was an unmitigated and even hostile critique of religion. According to Hillman, organized religion is either unconcerned or inimically set against the psyche’s expression of its soulful elements. This anti-religious sentiment is supported by various aspects of Hillman’s thought. However, Hillman did not fully appreciate the versatility of religion or its abilities to be soulful.1 Specifically, the Christian faith has historically expressed itself in a variety of ways which intersect with Hillman’s expressions of psyche, or soul. I argue that the lifestyle and teachings of the ancient desert fathers demonstrate a clear precedent of soulful expression from the Christian tradition that is aligned with Hillman’s own thinking. I will evaluate four elements of Hillman’s philosophy of psyche and demonstrate why each aspect is critical of religious appropriation. Subsequently, I will describe central features of the life and philosophy of the ancient desert fathers to attest that they indeed reached into the inner workings of the soul, according to Hillman’s philosophy. The work set out in this paper draws its importance based on Hillman’s school of psychology, known as archetypal psychology. Hillman’s school represents a burgeoning spiritual philosophy that is intellectually at odds with religion and the Christian faith. If it can be established that principles of Hillman’s school significantly overlap with an important part of the history of the Christian church than perhaps it can facilitate a communication between both traditions. I believe Christian spirituality would be substantialy emboldened by the potency and depth offered by Hillman’s thought. His work could bring to the theological discussion a richness of concepts otherwise absent. The concepts, such as archetypes, personality, depression, and the imaginal open new vistas for a Christian and archetypal conversation in the field of Christian spirituality to acknowledge the spiritual wealth in Hillman’s thought and begin to seriously examine Hillman’s numerous insights for living a contemporary life of soul. [End Page 149] A PREFACE FOR SPECIFICATIONS This paper will draw from the philosophy of James Hillman. Though philosophy may be a misnomer for Hillman’s thought,2 it is the best description given his treatment on comprehensive topics and his reexamination of intellectual assumptions. His philosophy, especially as it relates to his ideas of psyche, is best adumbrated in his work A Blue Fire.3 This work attempts to bring into focus connections between Hillman’s commentary on a variety of issues. In fact, it is outlined in such a way that is conducive to a philosophical program, namely, it begins with his most fundamental ideas and proceeds to build upon them a larger, cohesive body of thought composed of increasingly specific subjects. Hence, to have a good understanding of Hillman’s philosophy I will draw primarily from this work. Secondly, Hillman tends to treat organized religion with broad brush-strokes. He will frequently move back and forth between a critique of “spiritual disciplines” and specific arguments against Christian dogma. For the purposes of this paper, I will respond to his religious critiques by drawing from the Christian tradition exclusively. Hillman himself does this in practice as well. He almost exclusively levels his arguments against Christianity and derides its influence in the field of psychology. Thirdly, I will be discussing the desert fathers in the Christian tradition. This movement is an ancient, centuries-long movement located primarily in Egypt. It is important to note that much of the material I utilize will reference the great literary work to come out of this movement, the Apophthegmata Patrum. Translated as Sayings of the Fathers (hereafter referred to simply as Sayings), this collection gives a detailed and insightful look into the life and practices of the desert fathers. This movement represents an important historical age for Christianity and demonstrates a uniquely lived interpretation of Christianity. Moreover, I will also refer to the...

The vitality of fruit trees in ancient Bedouin orchards in the Arid Negev Highlands (Israel): Implications of climatic change and environmental stability

Thirty-seven sites with fruit tree orchards were found in the arid Negev Highlands of southern Israel. A variety of domesticated fruit trees were planted in these orchards, including date palm, fig, olive, pomegranate, almond, carob, pistachio, grapevine and bitter orange. The orchards were irrigated only by runoff water accumulating in runoff-harvesting systems built during the Byzantine and Early Muslim eras, some 1000–1500 years ago, which, despite their antiquity, are still vivid and occasionally fruit bearing today. The oldest olive trees seem to be direct descendants of trees planted during Byzantine times, whereas the youngest trees were planted by the Bedouin population of the Negev Highlands in the last few decades. The fact that the Bedouin population, with very little experience in agriculture, has succeeded to cultivate a large variety of fruit trees in the present harsh arid climate utilizing the historical agricultural installations has important environmental implications. It indicates that the original builders of the desert agriculture systems were highly sophisticated in transforming desert soil into arable land. However, this was achieved through hard labor, involving the construction of a vast number of stone dams and agricultural terraces to divert channels, and the clearing of rocky surfaces. This huge effort indicates that the climate and environment prevailing during the Byzantine–Early Muslim eras was equally harsh and arid; otherwise, the invested labor would not have been justified. We conclude that the Byzantine farmers, with their greater agricultural experience and long heritage in dry land agriculture, have achieved greater success than today Bedouin population, at cultivating of fruit trees under the harsh conditions of the Negev Highlands. Therefore we deduce that the ancient desert agriculture was not the outcome of better climate; rather, the climate prevailing during the relevant historical times was probably dry and harsh, much like today. The fact that the Bedouin population in that geograghical area is cultivating orchards utilizing the same constructions, and technologies indicates that the present environmental and climatic conditions were are suitable for practicing desert agriculture and have hardly changed since the Byzantine era.

Functional identification of Ammopiptanthus mongolicus anion channel AmSLAC1 involved in drought induced stomata closure

Drought, one of the most acute abiotic stressors plants encountered, can adversely affect plants growth and development. The fast adjustment of stomatal aperture is necessary for effective drought tolerance in plants. Anion channels were identified as important controllers of stomatal closing via mediating anion efflux. The present study reports the isolation and identification of a SLAC (SLOW ANION CHANNEL-ASSOCIATED 1) ortholog from an ancient desert shrub Ammopiptanthus mongolicus (Maxim.) Cheng f. (AmSLAC1), which is functionally conserved for ABA and drought induced stomata closure. AmSLAC1 was primarily expressed in shoots, especially in guard cells. The transcription of AmSLAC1 was induced in response to ABA and PEG treatments, implying the potential involvement in ABA-induced drought stress responses. Fluorescence observation suggested that AmSLAC1 was localized in the plasma membrane. BiFC asssays demonstrated an interaction between AmSLAC1 and the typical calcium-dependent protein kinases AmCPK6. Ectopic expression of AmSLAC1 restores a slac1-defective phenotype in Arabidopsis. Furthermore, anion conductance mediated by AmSLAC1 can be activated by AmCPK6 in Xenopus oocytes. Taken together, these results demonstrate that the expression of AmSLAC1 enables the complement of the phenotypes of Arabidopsis slac1 mutants, indicating that AmSLAC1, as an anion channel and regulated by AmCPK6, is functionally conserved for ABA and drought induced stomata closure.

Los microsatélites revelan una alta diferenciación genética entre las poblaciones nativas de Geoffroea decorticans en el desierto de Atacama chileno

Introducción y objetivos: Las condiciones extremas en el Desierto de Atacama de Chile son un obstáculo importante para la supervivencia de cualquier organismo. A pesar de esto, varias poblaciones de leguminosas de Geoffroea decorticans han prosperado en este entorno hostil y severo durante siglos. Aquí, tratamos de determinar la variabilidad genética en poblaciones de G. decorticans, dada su amplia distribución a través del Desierto de Atacama, el desierto más seco y antiguo de la Tierra. Los objetivos específicos del presente estudio fueron determinar el nivel de diversidad genética y evaluar la estructura genética en ocho poblaciones de G. decorticans del Desierto de Atacama chileno.M&M: Ochenta y cuatro individuos G. decorticans fueron seleccionados para muestreo en ocho localidades en el norte de Chile. Se utilizaron cinco microsatélites para analizar la diversidad genética, la diferenciación entre poblaciones, la estructura de la población y el flujo de genes.Resultados: La mayoría de las poblaciones analizadas del Desierto de Atacama mostraron una alta diversidad genética, con la excepción de PACH. Las poblaciones de G. decorticans (chañar) también mostraron una alta diferenciación genética y un flujo genético moderado dado por la barrera natural impuesta por el Desierto de Atacama. Las ocho poblaciones de chañar estudiadas se separaron en grupos de las regiones norte y sur.

A review of the rise and fall of ancient desert runoff agriculture in the Negev Highlands - A model for the southern Levant deserts

The rise and fall of desert agriculture in the southern Levant has been debated among scholars for the last 200 years, in the chronological, the socio-political and the environmental context. Based on c. 31 OSL ages of sediments from agricultural terraces in various sites in the Negev Highlands, the main phase of ancient desert agriculture was dated to between the 3rd-4th centuries CE and the 10th-11th centuries CE (Avni et al., 2013). Within this longue durée process of agricultural activities, no significant environmental or climatic change was observed coinciding with the Byzantine- Islamic transition in the 7th century CE.Our research, which focused on the natural processes that influenced the rise and fall of the Negev desert agriculture, found that the agricultural installations were sustainable for at least 700 years and parts of these agricultural constructions are still in use today. This long period of usage is a clear indication of their robust design and their good adaptation to the desert environment, despite possible short-term climatic fluctuations. However, continuous flooding, gulling, soil erosion and siltation required constant maintenance of agricultural systems by the local farmers. In addition, the political and economic changes that followed the Byzantine-Islamic transition triggered a gradual decrease in the economic value of the products of desert agriculture, followed by a disruption of the social-political balance between local farmers and herders. These made the desert runoff agriculture less viable, leading to its final demise after the 10th century CE. Therefore, a direct link between the rise and fall of desert runoff agriculture and the claimed climatic changes in the southern Levant seems unlikely.

Functional analysis of a type 2C protein phosphatase gene from Ammopiptanthus mongolicus

In Arabidopsis and certain other plant species, the type 2C protein phosphatases (PP2Cs) of the clade A class have been demonstrated to act as negative regulators in ABA-induced stress responses, such as stomatal closure. The present study reports the identification of a PP2C ortholog from the ancient desert shrub Ammopiptanthus mongolicus (Maxim.) Cheng f. (AmPP2C), which is functionally conserved over its counterparts reported from other plant species. AmPP2C was primarily expressed in leaves, with strong transcriptional accumulation being observed in the guard cells. The expression of AmPP2C was induced in response to PEG or ABA treatments, implying the potential involvement in ABA-induced stress responses. The GFP-tagging observation revealed that AmPP2C was predominantly localized to the nuclei and partly to the cytoplasm. Furthermore, BiFC assays demonstrated an interaction between AmPP2C and the typical protein kinase SnRK2.6 (AmOST1). Overexpression of AmPP2C in Arabidopsis significantly overcame the inhibition of seed germination by ABA. The transgenic Arabidopsis lines exhibited larger stomatal apertures and significantly reduced sensitivity to ABA-induced stomatal closure, which subsequently led to greater water loss and decreased biomass under PEG-simulated drought stress treatments. Under limited nitrogen or potassium supplements, plants overexpressing AmPP2C obtained a superior capability of nitrogen (N) and potassium (K) acquisition in the green parts. Therefore, the impairment of ABA-induced stomatal closure rendered by the function of PP2C helped to identify a potential survival strategy in plants suffering persistent drought stress via the maintenance of the necessary mineral nutrient acquisition driven by transpirational solute flow.

Hybrid Modes of Architectural Production in the United Arab Emirates

Abstract This article presents a recent design exercise in which architecture students from the American University of Sharjah were asked to design a sustainable scientific research facility with associated housing in the desert oasis city of Al Ain in the United Arab Emirates. The studio investigated vernacular habitation patterns and crafts of ancient desert dwellers in order to develop techniques for inhabiting this harsh environment. The vernacular techniques examined have allowed people to exist in the region for tens of thousands of years and include courtyard house typologies, ‘arish (palm-leaf) construction, nomadic Bedouin weaving, mashrabiya (latticework) screens, dhow boat-making, sand baffles, sewn lateen (triangular) sails, wind towers and qanat (irrigation) channels, to name a few. The students examined and reinterpreted these techniques to align them with modern construction requirements and contemporary ways of living. Using ‘hybrid’ models, the students made small-scale fabrications partly determined by the site, and in so doing created proposals that were extremely site-specific and therefore inherently sustainable. In contrast to the highly incongruous development patterns of such contemporary urban environments as Dubai and Abu Dhabi, the architectural approach that emerged from this exercise aspires to be environmentally sensitive while maintaining cultural authenticity.

The world\u2019s earliest Aral-Sea type disaster: the decline of the Loulan Kingdom in the Tarim Basin

Remnants of cities and farmlands in China’s hyperarid Tarim Basin indicate that environmental conditions were significantly wetter two millennia ago in a region which is barren desert today. Historical documents and age data of organic remains show that the Loulan Kingdom flourished during the Han Dynasty (206 BCE–220 CE) but was abandoned between its end and 645 CE. Previous archaeological, geomorphological and geological studies suggest that deteriorating climate conditions led to the abandonment of the ancient desert cities. Based on analyses of lake sediments from Lop Nur in the eastern Tarim Basin and a review of published records, we show that the Loulan Kingdom decline resulted from a man-made environmental disaster comparable to the recent Aral Sea crisis rather than from changing climate. Lop Nur and other lakes within the Han Dynasty realm experienced rapidly declining water levels or even desiccation whilst lakes in adjacent regions recorded rising levels and relatively wet conditions during the time of the Loulan Kingdom decline. Water withdrawal for irrigation farming in the middle reaches of rivers likely caused water shortage downstream and eventually the widespread deterioration of desert oases a long time before man initiated the Aral Sea disaster in the 1960s.