Search Results (205)

The long-term trend of coastal upwelling under global warming has been a research focus in recent years. Based on datasets including sea surface temperature (SST), sea surface wind, air–sea heat fluxes, ocean currents, and sea level pressure, this study explores the long-term trend and underlying mechanisms of the Oman coastal upwelling intensity in summer during 1993–2018. The results indicate a persistent decrease in SST within the Oman upwelling region during this period, suggesting an intensification trend of Oman upwelling. This trend is primarily driven by the strengthened positive wind stress curl (WSC), while the enhanced net shortwave radiation flux at the sea surface partially suppresses the SST cooling induced by the strengthened positive WSC, and the effect of horizontal oceanic heat transport is weak. Further analysis revealed that the increasing trend in the positive WSC results from the nonuniform responses of sea level pressure and the associated surface winds to global warming. There is an increasing trend in sea level pressure over the western Arabian Sea, coupled with decreasing atmospheric pressure over the Arabian Peninsula and the Somali Peninsula. This enhances the atmospheric pressure gradient between land and sea, and consequently strengthens the alongshore winds off the Oman coast. However, in the coastal region, wind changes are less pronounced, resulting in an insignificant trend in the alongshore component of surface wind. Consequently, it results in the increasing positive WSC over the Oman upwelling region, and sustains the intensification trend of Oman coastal upwelling. Full article

The increasing global discovery of plant species presents both opportunities and challenges, particularly in distinguishing between beneficial and poisonous varieties. While computer vision techniques show promise for classifying plant species and predicting toxicity, the lack of comprehensive datasets including images, scientific names, descriptions, local names, and poisonous status complicates these predictions. In this paper, we propose an Explainable Deep Inherent Learning approach that leverages advanced computer vision techniques for effective plant species classification and poisonous status prediction. The proposed Deep Inherent Learning method was validated using different explanation techniques, and Explainable AI (XAI) was employed to clarify decision-making processes at both the local and global levels. Additionally, we provide visual information to enhance trust in the proposed method. To validate the efficacy of our approach, we present a case study involving 2500 images of 50 different plant species from the Arabian Peninsula, enriched with essential metadata. This research aims to reduce the incidence of poisoning from harmful plants, thereby benefiting individuals and society. Our experimental results demonstrate strong performance, with the XAI model achieving accuracy, Precision, Recall, and F1-Score of 0.94, 0.96, 0.96 and 0.97, respectively. By enhancing interpretability, our study fosters greater trust in AI-driven plant classification systems. Full article

This study presents a global aerosol climatology derived from six years (October 2018–October 2024) of the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) observations, using a U-Net Convolutional Neural Network (CNN) machine learning algorithm for Cloud–Aerosol Discrimination (CAD). Despite ICESat-2’s design primarily as an altimetry mission with a single-wavelength, low-power, high-repetition-rate laser, ICESat-2 effectively captures global aerosol distribution patterns and can provide valuable insights to bridge the observational gap between the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) missions to support future spaceborne lidar mission design. The machine learning approach outperforms traditional thresholding methods, particularly in complex conditions of cloud embedded in aerosol, owing to a finer spatiotemporal resolution. Our results show that annually, between 60°S and 60°N, 78.4%, 17.0%, and 4.5% of aerosols are located within the 0–2 km, 2–4 km, and 4–6 km altitude ranges, respectively. Regional analyses cover the Arabian Sea (ARS), Arabian Peninsula (ARP), South Asia (SAS), East Asia (EAS), Southeast Asia (SEA), the Americas, and tropical oceans. Vertical aerosol structures reveal strong trans-Atlantic dust transport from the Sahara in summer and biomass burning smoke transport from the Savanna during dry seasons. Marine aerosol belts are most prominent in the tropics, contrasting with earlier reports of the Southern Ocean maxima. This work highlights the importance of vertical aerosol distributions needed for more accurate quantification of the aerosol–cloud interaction influence on radiative forcing for improving global climate models. Full article

Rodents are among the most abundant and ecologically diverse mammals, playing key roles in terrestrial ecosystems and often serving as reservoirs for various zoonotic and wildlife pathogens. Among these are protozoan parasites of the genera Hepatozoon and Theileria, which are known to infect a wide range of domestic and wild animals worldwide. However, little is known about the diversity and phylogenetic relationships of these hemoprotozoans in rodent hosts, particularly in the Arabian Peninsula. The aim of this study was to investigate the presence and genetic diversity of Hepatozoon sp. and Theileria sp. in rodents from different regions of Saudi Arabia and to determine potential reservoir species. A total of 111 rodents were captured and identified by molecular analysis of the mitochondrial 16S rRNA gene. Screening for parasites was performed using PCR amplification of the 18S rRNA gene, followed by sequencing, haplotype analysis, and phylogenetic reconstruction using both maximum likelihood and Bayesian inference methods. Our results represent the first molecular detection of Hepatozoon sp. in Arvicanthis niloticus (31.3%), Gerbillus cheesmani (26.5%), G. nanus (28.5%), and Rattus rattus (32.0%) and of Theileria sp. in G. nanus (21.5%) and R. rattus (24.0%) in Saudi Arabia. Haplotype network analysis revealed seven distinct Hepatozoon haplotypes forming a star-like cluster, suggesting host specificity. One divergent haplotype (Hap_2), 19 mutation steps apart, may represent a novel lineage. Phylogenetic analyses grouped Saudi Hepatozoon sequences with those from reptiles and rodents, forming a clade distinct from sequences isolated from felids and canids. In contrast, Theileria sequences showed low diversity, clustering with a single widespread haplotype found in rodents and ruminants in several regions. These findings significantly expand the current knowledge on rodent-associated apicomplexan parasites in Saudi Arabia, revealing novel Hepatozoon haplotypes and highlighting the role of rodents in the transmission of reptile-associated Hepatozoon spp. This study provides basic molecular data crucial to understanding host–parasite relationships and the potential public and veterinary health implications of these parasites in arid ecosystems. Full article

On 3 February 2006, a powerful Mediterranean cyclone instigated a widespread dust storm across Saudi Arabia. Meteorological observations from one station recorded strong westerly to southwesterly winds, with gusts reaching 40 m/s, accompanied by thunderstorms and dust storms. This study delves into the formation and development of this significant Mediterranean cyclone, which impacted the Mediterranean basin and the Arabian Peninsula from 26 January to 4 February 2006. Utilizing ECMWF ERA5 reanalysis data, this research analyzes the synoptic and dynamic conditions that contributed to the cyclone’s evolution and intensification. The cyclone originated over the North Atlantic as cold air from higher latitudes and was advected southward, driven by a strong upper-level trough. The initial phase of cyclogenesis was triggered by baroclinic instability, facilitated by an intense upper-level jet stream interacting with a pre-existing low-level baroclinic zone over coastal regions. Upper-level dynamics enhanced surface frontal structures, promoting the formation of the intense cyclone. As the system progressed, low-level diabatic processes became the primary drivers of its evolution, reducing the influence of upper-level baroclinic mechanisms. The weakening of the upper-level dynamics led to the gradual distortion of the low-level baroclinicity and frontal structures, transitioning the system to a more barotropic state during its mature phase. Vorticity analysis revealed that positive vorticity advection and warm air transport toward the developing cyclone played key roles in its intensification, leading to the development of strong low-level winds. Atmospheric kinetic energy analysis showed that the majority of the atmospheric kinetic energy was concentrated at 400 hPa and above, coinciding with intense jet stream activity. The generation of the atmospheric kinetic energy was primarily driven by cross-contour flow, acting as a major energy source, while atmospheric kinetic energy dissipation from grid to subgrid scales served as a major energy sink. The dissipation pattern closely mirrored the generation pattern but with the opposite sign. Additionally, the horizontal flux of the atmospheric kinetic energy was identified as a continuous energy source throughout the cyclone’s lifecycle. Full article

Cultivating crops in the hot, arid conditions of the Arabian Peninsula often requires irrigation with brackish water, which exposes plants to salinity and heat stress. Timely, cost-effective monitoring of plant health can significantly enhance crop management. In this context, remote sensing techniques offer promising alternatives. This study evaluates several low-cost, ground-level remote sensing methods and compares them with benchmark analytical techniques for assessing salt stress in two economically important woody species, moringa and pomegranate. The species were irrigated under three salinity levels: low (2 dS m⁻¹), medium (5 dS m⁻¹), and high (10 dS m⁻¹). Remote sensing tools included RGB, multispectral, and thermal cameras mounted on selfie sticks for canopy imaging, as well as portable leaf pigment and chlorophyll fluorescence meters. Analytical benchmarks included sodium (Na) accumulation, carbon isotope composition (δ¹³C), and nitrogen (N) concentration in leaf dry matter. As salinity increased from low to medium, canopy temperatures, vegetation indices, and δ¹³C values rose. However, increasing salinity from medium to high levels led to a rise in Na accumulation without further significant changes in other remote sensing and analytical parameters. In moringa and across the three salinity levels, the Normalized Difference Red Edge (NDRE) and leaf chlorophyll content on an area basis showed significant correlations with δ¹³C (r = 0.758, p < 0.001; r = 0.423, p < 0.05) and N (r = 0.482, p < 0.01; r = 0.520, p < 0.01). In pomegranate, the Normalized Difference Vegetation Index (NDVI) and chlorophyll were strongly correlated with δ¹³C (r = 0.633, p < 0.01 and r = 0.767, p < 0.001) and N (r = 0.832, p < 0.001 and r = 0.770, p < 0.001). Remote sensing was particularly effective at detecting plant responses between low and medium salinity, with stronger correlations observed in pomegranate. Full article

The Arabian leopard (Panthera pardus nimr), a critically endangered subspecies endemic to the Arabian Peninsula, faces severe threats from habitat loss, prey depletion, and inbreeding, with fewer than 200 individuals remaining. Genomic resources for this subspecies have been scarce, limiting insights into its evolutionary history and conservation needs. Here, we present the first complete mitochondrial DNA (mtDNA) sequence of P. pardus nimr, derived from a wild-born male sampled at the Oman Wildlife Breeding Centre in 2023. Using PacBio HiFi sequencing, we assembled a 16,781 bp mitogenome (GenBank: PQ283265) comprising 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and a control region, with a GC content of 40.94%. Phylogenetic analysis, incorporating 17 Panthera mtDNA sequences, positions P. pardus nimr closest to African leopard populations from South Africa (Panthera pardus), while distinguishing it from Asian subspecies (P. pardus japonensis and P. pardus orientalis). This mitogenome reveals conserved vertebrate mitochondrial structure and provides a critical tool for studying Panthera genus evolution. Moreover, it enhances conservation genetics efforts for P. pardus nimr by enabling population structure analysis and informing breeding strategies to strengthen its survival. Full article

The insectivores (order Eulipotyphla) of Saudi Arabia consist of six species in four genera within two families (Erinaceidae and Soricidae). Details on the past and present distribution of the insectivores are included as well as illustrations for each species, along with available data on their habitat preferences and biology. The Ethiopian hedgehog, Paraechinus aethiopicus, was the most common species inhabiting the arid deserts of Saudi Arabia. An analysis of the insectivorous fauna of Saudi Arabia revealed that they have two major zoogeographical affinities: the Palaearctic (Hemiechinus auratus, Paraechinus hypomelas and Crocidura gueldenstaedtii) and Afrotropical–Palaearctic (Paraechinus aethiopicus), which are endemic to the Arabian Peninsula (Crocidura dhofarensis), and one introduced species (Suncus murinus). Southwestern Saudi Arabia has the highest species richness. The Arabian white-toothed shrew, Crocidura arabica, is expected to occur in the extreme southwest. The conservation status and threats affecting insectivores in Saudi Arabia are highlighted. Full article

Water, often described as the elixir of life, is a critical resource that sustains life on Earth. The acute water scarcity in the major basins of the Arabian Peninsula has been further aggravated by rapid population growth, urbanization, and the impacts of climate change. This situation underscores the urgent need for a comprehensive analysis of the region’s morphometric characteristics. Such an analysis is essential for informed decision-making in water resource management, infrastructure development, and conservation efforts. This study provides a foundational basis for implementing sustainable water management strategies and preserving ecological systems by deepening the understanding of the unique hydrological processes within the Arabian Peninsula. Additionally, this research offers valuable insights to policymakers for developing effective flood mitigation strategies by identifying vulnerable areas. The study focuses on an extensive investigation and assessment of morphometric parameters in the primary basins of the Arabian Peninsula, emphasizing their critical role in addressing water scarcity and promoting sustainable water management practices. The findings reveal that the Arabian Peninsula comprises 12 major basins, collectively forming a seventh-order drainage system and covering a total land area of 3.24 million km². Statistical analysis demonstrates a strong correlation between stream order and cumulative stream length, as well as a negative correlation between stream order and stream number (R² = 99%). Further analysis indicates that many of these basins exhibit a high bifurcation ratio, suggesting the presence of impermeable rocks and steep slopes. The hypsometric integral (HI) of the Peninsula is calculated to be 60%, with an erosion integral (EI) of 40%, indicating that the basin is in a mature stage of geomorphological development. Importantly, the region is characterized by a predominantly coarse drainage texture, limited infiltration, significant surface runoff, and steep slopes, all of which have critical implications for water resource management. Full article

Geochemical and isotopic analysis of bitumen lining potsherds from the al-Qusur monastery (second half of the 7th c. CE and the middle of the 9th c. CE), at the central part of Failaka Island (Kuwait Bay), confirms the presence of two distinct compositional categories that can be matched to contemporary sources from two different areas of Iran: the Kermanshah province on one side, and the Khuzestan–Fars–Busher provinces on the other side. Potsherds comprise different types: TORP-S amphorae, TORP-C amphorae, SPORC storage jar, turquoise alkaline-glazed jar (TURQ.T), and CREAC jar. There is no relationship between the type of potsherd and the origin of bitumen. The bitumen coating SPORC jar, first identified as a kind of juice strainer to filter the «garum-like juice», was examined in greater details to try to identify traces of fish sauce mentioned in the Arabic kitchen books as ‘murri’, and quite similar to the Roman garum. The mineralogical analysis exhibits the classical minerals of archaeological mixtures (quartz, calcite, dolomite) and no halite. Hydrocarbons, alcohols, and methyl esters show a typical biodegraded bitumen signature but no fatty acids and terpenoids. It seems that the bitumen matrix has not adsorbed any molecules from the presumed «garum» filtered in the basin. Full article

Acacia species are important trees in arid ecosystems due to their diverse ecological roles, such as providing vegetation cover, community structures, food resources for animals, soil stabilization, and erosion prevention. However, in the Arabian Peninsula, Acacia species are declining due to climate change, overgrazing, and fuelwood harvesting. This study evaluates the effectiveness of various pre-sowing treatments—sulfuric acid soaking and tap and hot water soaking—on breaking seed dormancy to enhance germination in nine Acacia species native to the Al-Baha region of Saudi Arabia. The key germination indicators assessed were the mean germination time (MGT), germination percentage (GP), and germination index (GI). Sulfuric acid treatments for 10–15 min reduced the MGT and increased the GP for A. etbaica, A. hamoulosa, and A. tortilis, while A. origena responded best to 1 min of hot water soaking. Conversely, A. asak, A. ehrenbergiana, and A. johnwoodii showed little to no germination improvement with treatment and A. oerfota and A. gerrardii showed no germination improvement, indicating the need for alternative methods. These findings indicate that the seed germination requirements vary within Acacia spp. from the same geographic region and similar climatic conditions. Further work is required for five of the species tested to develop better seed germination techniques, given the potential utility of Acacia spp., in ecological restoration and sustainable land management in arid regions. Full article

Background and Aim: This systematic scoping review examines rabies-related incidents, interventions, and post-exposure immunoprophylaxis in the Arabian Gulf region and Saudi Arabian Peninsula. Methods: A comprehensive literature search was conducted in databases including PubMed, Scopus, WoS, MedLine, and Cochrane Library up to July 2024. Studies were included discussing the reported cases of rabies that received the PEP in all countries of the Arabian Gulf, their epidemiological data, the received schedules of vaccination, and their safety. The search was done by using the following terminologies: rabies vaccine, rabies human diploid cell vaccine, vaccine, Saudi Arabia, Bahrain, Iraq, Kuwait, Oman, Qatar, United Arab Emirates, Southwest Asia, Iran, West Asia, Western Asia, Persian Gulf, Arabian Gulf, Gulf of Ajam, Saudi Arabian Peninsula, and The Kingdom of Saudi Arabia. Results: The systematic scoping review included 36 studies, synthesizing findings from diverse research designs, including large-scale cross-sectional studies and case reports, spanning nearly three decades. Findings indicated that young males in urban areas are most at risk for animal bites, predominantly from domestic dogs and cats. While post-exposure prophylaxis (PEP) was generally administered within recommended timeframes, vaccination completion rates varied. Conclusions: The review highlighted gaps in public awareness about rabies risks and prevention. Vaccine safety profiles were generally favorable, with mostly mild-to-moderate side effects reported. The study underscores the need for enhanced public health education, standardized PEP protocols, and a One Health approach to rabies prevention. Full article

Eurasian drylands are vital for the global climate and ecological balance. Quantifying spatiotemporal variations in surface soil moisture (SSM) is essential for monitoring water, energy, and carbon cycles. The suitability of recent global-scale surface soil moisture datasets for Eurasian arid and semi-arid regions has not been comprehensively evaluated. This study investigates spatiotemporal trends of five SSM products—MERRA-2, ESACCI, GLEAM, GLDAS, and ERA5—from 1980 to 2023. The performance of these products was evaluated using in situ station data and the three-cornered hat (TCH) method, followed by partial correlation analysis to assess the influence of environmental factors, including mean annual temperature (MAT), mean annual precipitation (MAP), potential evapotranspiration (PET), vapor pressure deficit (VPD), and leaf area index (LAI), on SSM from 1981 to 2018. The results showed consistent SSM patterns: higher values in India, the North China Plain, and Russia, and lower values in the Arabian Peninsula, the Iranian Plateau, and Central Asia. Regionally, MAT, PET, VPD, and LAI increased significantly (0.04 °C yr⁻¹, 1.66 mm yr⁻¹, 0.004 kPa yr⁻¹, and 0.003 m² m⁻² yr⁻¹, respectively; p < 0.05), while MAP rose non-significantly (0.29 mm yr⁻¹). ERA5 exhibited the strongest correlation with in situ station data (R² = 0.42), followed by GLEAM (0.37), ESACCI (0.28), MERRA2 (0.19), and GLDAS (0.17). Additionally, ERA5 showed the highest correlation (correlation = 0.72), while GLEAM had the lowest bias (0.03 m³ m⁻³) and ESACCI exhibited the lowest ubRMSE (0.03 m³ m⁻³). The three-cornered hat method identified ERA5 and GLDAS as having the lowest uncertainties (<0.03 m³ m⁻³), with ESACCI exceeding 0.05 m³ m⁻³ in northern regions. Across land cover types, cropland had the lowest uncertainty among the five SSM products, while forest had the highest. Partial correlation and dominant factor analysis identified MAP as the primary driver of SSM. This study comprehensively evaluated SSM products, highlighting their strengths and limitations. It underscored MAP’s crucial role in SSM dynamics and provided insights for improving SSM datasets and water resource management in drylands, with broader implications for understanding the hydrological impacts of climate change. Full article

The Arabian sand gazelle (Gazella marica) is a native and highly adaptable species of the Arabian Peninsula. Due to drastic population declines, the species is listed as globally vulnerable. Very little is known about the behavioral ecology of this species in captivity; therefore, this study was designed to investigate the seasonal variations in the activity patterns of Arabian sand gazelles at Al Reem Biosphere Reserve, Qatar. Data were collected in two phases, i.e., summer (September–October 2021) and winter (December 2021–January 2022), for a total of 16 days. Results revealed that feeding and walking (p = 0.001) were the dominant activities in both seasons, yet these were higher in summer compared to winter. Likewise, standing, lying down and other activities (social interactions, defecating, maintenance, sexual behaviors) were also higher in summer compared to winter. All these findings suggest that Arabian sand gazelles are adaptable to harsh environments. However, we strongly recommend a year-round investigation on the impacts of humans, feed types and Arabian Oryx on the behavioral activities of Arabian sand gazelles. In addition, we suggest studying the behavior ecology of the wild scattered populations of Arabian sand gazelles for better management of captive breeding stocks. Full article

Wadi Al-Rummah is one of the most important geographical phenomena in the Najd region of Saudi Arabia and is considered to be the largest and longest valley in the Arabian Peninsula, with most of its basin located in the Qassim region. This valley is the habitat of diverse flora, including medicinal herbs, plants, and trees. Three plant species, namely, Capparis spinosa L., Haloxylon salicornicum, and Zygophyllum propinquum were selected for their phytochemical analyses. The effect of soil and climatic conditions on the plant metabolites was investigated. Plant samples were collected at the beginning of March (winter) and the end of August (summer) separately to evaluate the effect of climatic conditions on plant components and their medicinal value. Soil samples were also collected for analysis to find any correlation between plant components and soil composition. Soil and plant samples were collected during the late winter and late summer of the same year. Quantitative analyses of soil samples showed differences in soil phosphorus, iron, magnesium, and as well as pH. These elements were higher in winter than in summer. On the other hand, nitrogen and electrical conductivity were higher in summer. However, there were no significant differences between summer and winter for calcium, potassium, sodium, bulk density, and soil water content. Physiological and biochemical analyses on the aerial parts of the selected plants showed significant differences in carbohydrate content between summer and winter. In fact, they were higher in winter for all the plants studied. Lipid content was higher in summer than in winter. The protein contents of C. spinosa L. were 14% higher in winter, while those of H. salicornicum were 21% higher in summer. Z. propinquum proved to be the most salt-tolerant plant, followed by C. spinosa L. and H. salicornicum. The alkaloid and saponin content of the plants was higher in summer than in winter. There was no significant difference between summer and winter in the levels of phenolic compounds and flavonoids in the plants studied. Based on these results, seasonal changes appear to significantly affect certain medicinal compounds, while other compounds remain relatively constant throughout the year. Full article