Western Desert Oases Research Articles

Distribution, composition and risk assessment of hydrocarbon residue in surficial sediments of El-Dakhla, El-Kharga and El-Farafra oases, Egypt.

This work examined the polycyclic aromatic hydrocarbons (PAHs) and n-alkanes quantities, sources, and hazards in sediments collected from the Egyptian Western Desert Oases namely: Dakhla, Kharga and Farafra oases. The n-alkane (C9-C20) residue concentrations have ranged from 0.66 to 2417.91 µg/g recorded for the three Oases. On the other hand, the total n-alkane ranged from 448.54 µg/g to 8442.60 µg/g. Higher carbon preference index (CPI) values (> 1.0) proposed that the natural sources could be the main contributor to n-alkanes in the Oases sediment. GC-MS/MS (selected reaction monitoring (SRM) method) was used for the determination of the ΣPAHs concentrations in the studied sediments. The ΣPAHs concentrations (ng/g, dry weight) in the studied three Oases varied from 10.18 to 790.14, 10.55 to 667.72, and from 38.27 to 362.77 for the Kharga, Dakhla and Farafra Oases, respectively. The higher molecular weight PAHs were the most abundant compounds in the collected samples. Assessing potential ecological and human health issues highlighted serious dangers for living things and people. All the investigated PAHs had cancer risk values between 1.43 × 10-4 and 1.64 × 10-1, this finding suggests that PAHs in the samples under study pose a moderate risk of cancer. The main sources of PAHs in this study are biomass, natural gas, and gasoline/diesel burning emissions.

Chlorinated pesticides and PCB residues in the Egyptian Western Desert oases sediments

This preliminary investigation aimed to detect concentrations of chlorinated pesticides and PCBs in 40 sediment samples from three desert oases located in Kharga, Dakhla and Farafra in western Egypt. The residues of 18 PCBs and 16 chlorinated pesticides were measured by GC–MS/MS (SRM) method. The results showed that PCBs and pesticides were present in all studied samples. The concentrations of individual PCBs ranged from undetected to 3.99 ng/g dw in all these sediment samples. The total residue of pesticides (ng/g, dry weight) in sediment samples also varied from 5.18 to 25.92, 5.41 to 29.49, and 5.93 to 24.19 ng/g dw for the Kharga, Dakhla and Farafra Oases, respectively. The concentrations of PCBs and chlorinated pesticides detected in these oasis sediments were lower than that reported for other worldwide locations. According to the recorded concentrations in this baseline study of PCBs and total DDTs, the results revealed the minimal risks to organisms and people in the studied area according to the Effects Range-Low (ERL) and Effects Range-Median (ERM) guideline values.

Land Degradation Vulnerability Mapping in a Newly-Reclaimed Desert Oasis in a Hyper-Arid Agro-Ecosystem Using AHP and Geospatial Techniques

Modelling land degradation vulnerability (LDV) in the newly-reclaimed desert oases is a key factor for sustainable agricultural production. In the present work, a trial for using remote sensing data, GIS tools, and Analytic Hierarchy Process (AHP) was conducted for modeling and evaluating LDV. The model was then applied within 144,566 ha in Farafra, an inland hyper-arid Western Desert Oases in Egypt. Data collected from climate conditions, geological maps, remote sensing imageries, field observations, and laboratory analyses were conducted and subjected to AHP to develop six indices. They included geology index (GI), topographic quality index (TQI), physical soil quality index (PSQI), chemical soil quality index (CSQI), wind erosion quality index (WEQI), and vegetation quality index (VQI). Weights derived from the AHP showed that the effective drivers of LDV in the studied area were as follows: CSQI (0.30) > PSQI (0.29) > VQI (0.17) > TQI (0.12) > GI (0.07) > WEQI (0.05). The LDV map indicated that nearly 85% of the total area was prone to moderate degradation risks, 11% was prone to high risks, while less than 1% was prone to low risks. The consistency ratio (CR) for all studied parameters and indices were less than 0.1, demonstrating the high accuracy of the AHP. The results of the cross-validation demonstrated that the performance of ordinary kriging models (spherical, exponential, and Gaussian) was suitable and reliable for predicting and mapping soil properties. Integrated use of remote sensing data, GIS, and AHP would provide an effective methodology for predicting LDV in desert oases, by which proper management strategies could be adopted to achieve sustainable food security.

Integrative Taxonomic, Ecological and Genotyping Study of Charophyte Populations from the Egyptian Western-Desert Oases and Sinai Peninsula.

Present-day information available on the charophyte macroalgae in Egypt, including their phylogenetic affinities, remains largely incomplete. In this study, nine charophyte populations were collected from different aquatic biotopes across the Egyptian Western-Desert Oases and Sinai Peninsula. All populations were investigated using an integrative polyphasic approach including phylogenetic analyses inferred from the chloroplast-encoded gene (rbcL) and the internal transcribed spacer (ITS1) regions, in parallel with morphotaxonomic assignment, ultrastructure of the oospore walls, and autecology. The specimens identified belonged to the genera Chara, Nitella, and Tolypella, with predominance of the first genus to which five species were assigned though they presented some interesting aberrant taxonomic features: C. aspera, C. contraria, C. globata, C. tomentosa, and C. vulgaris. Based on our integrative study, the globally rare species C. globata was reported for the second time for the whole African continent. The genus Nitella was only represented by N. flagellifera, and based on the available literature, it is a new record for North Africa. Noteworthy, an interesting Tolypella sp., morphologically very similar to T. glomerata, was collected and characterized and finally designated with the working name ‘Tolypella sp. PBA–1704 from a desert, freshwater wetland’, mainly based on its concatenated rbcL+ITS1 phylogenetic position. This study not only improved our understanding on the diversity, biogeography and autecological preferences of charophytes in Egypt, but it also broadened our knowledge on this vulnerable algal group in North Africa, emphasizing the need of more in-depth research work in the future, particularly in the less–impacted desert habitats.

Morphometric Comparison Between Different Populations of Darkling Beetles “Pimilia nilotica (Coleoptera: Tenebrionidae)” In Egypt

Insects include almost 60% of the described eukaryotic animals worldwide. However, the morphological measurements and assessment of the effects of isolation and habitat still lack many insect groups. The current study aimed to compare the morphometric measurements of dissimilar populations of darkling beetles “Pimelia nilotica” in Egypt. A variable comparison of morphometric variations was taken by a threaded micrometer for six different eco-geographical regions from Egypt fall under the Western Mediterranean Coastal Desert, Western Desert Oases, El-Faiyum Depression, the Eastern Desert, Nile Delta, and South Sinai. Twenty-one morphometric measurements were taken in the currents study. Traits best reminiscent of the excellence of populations were distinguished by cluster analysis, and also by the principal component analysis. The primary and second discriminants scores (score 1 and score 2) recorded 76.4% and 23.8%, respectively, of the full variation in samples. Multiple discriminant analysis disclosed clear morphometric differences between Western Desert, Eastern Desert, El-Faiyum Depression, and South Sinai populations. Traits clarifying the maximum of the changeability among populations were those associated with the morphological estimations.

Morphometric Comparison Between Different Isolated Populations of Ocnera sparsispina (Coleoptera: Tenebrionidae) in Egypt

The present study aimed to compare morphometric measurements of different populations of Ocnera sparsispina in Egypt. A multivariate comparison of morphometric differences was undertaken by eyepiece micrometer on five different ecogeographical regions from Egypt fall under; Western Mediterranean Coastal Desert, Western Desert Oases, El Faiyum Depression, Nile Delta, and Sinai. Seventeen absolute morphometric characters and 4 ratios for 412 specimens undertaken. Traits best corresponding to the distinction of populations were distinguished by cluster analysis and the linear discriminant analysis. The first and second discriminant scores (score1 and score2) recorded 77.3% and 22.7%, respectively, of the total variation in samples. Multiple discriminant analysis revealed clear morphometric differences between the Ocnera sparsispina populations collected from 5 different ecogeographical regions of Egypt, and they are clustered in two discrete groups

Noms de famille dans les oasis d’Égypte à l’époque ottomane

Abstract Very little is known about the existence of family names in Ottoman Egypt, except among the upper classes and urban society as a whole. In this respect, the Western Desert Oases of Dakhla and Kharga provide us with an exceptional documentation. Cross referencing texts found or still preserved in local family archives with the results of ethnographical fieldwork conducted over a century, enables us to reconstruct the onomastic culture of the Oases society through the last four centuries. Family names were in use among most of the inhabitants. This use developed in a complex way, by combining lineage names created a few generations ago with more ancient and inclusive names. Their combined use allowed to identify and classify all the inhabitants of a settlement, without knowing them personally. It reflects a non-tribal society, largely based on the ownership of scarce but perennial water resources, a key factor in the longevity of families.

Land capability classification of some western desert Oases, Egypt, using remote sensing and GIS

Two desert Oases (i.e. Al-Kharga and Al-Dakhla), located in the western desert of Egypt, were selected as case studies. Soil, ETM+ satellite images, climatic and landscape database, were integrated through a GIS model. Digital Elevation Model (DEM) was elaborated using SRTM space images, in addition to spot heights and contour lines, derived from topographic maps. The created land resource database was used to evaluate and map land capabilities on bases of FAO (1985) methodology.The obtained data indicate that the highly capable soils represent 24.5% of Al-Kharga Oases and 19.2% of Al-Dakhla Oases. These soils are associated with the Typic Haplotorrerts and Typic Torrifluvents sub-great groups. The moderately capable soils represent 1.5% of the total area of Al-Kharga Oases and 6.1% of Al-Dakhla Oases. They were found to be associated with sub-great group soil Typic Torriorthents. The low capable soils represent 36.0% of Al-Kharga Oases total area and 20.3% of Al-Dakhla Oases; this class is associated with the soils of Torripsamments great group. The rest of the Oases are considered as non-capable soils or rock land, representing 38.0% of Al-Kharga Oases total area and 54.5% of Al-Dakhla Oases.It could be concluded that the desert Oases are sustainable areas, which might have potential importance supporting the national development programs. Integrating remote sensing data with digital soil map, using GIS, led to the elaboration of successful land capability classification mapping.

Hydrochemical characteristics of Egypt western desert oases groundwater

In this study, the distribution of the chemical con- stituents (major, minor, and trace elements) is determined in different localities in Egypt's western desert oases, i.e., Bahariya, Farafra, Bahrean, Siwa, El-Gara, and Al-Jaghbub oases. The Nubian Sandstone Aquifer (NSA) is shared be- tween all oases; however, the Limestone Aquifer (LA) is shared only between the western oases, i.e., Bahrean, Siwa, El-Gara, and Al-Jaghbub. The LA is usually located above NSA in Egypt's western desert. The results indicate notable difference in chemical characteristics between the LA and the NSAwaters. Under furrow surface irrigation systems that are commonly used in the Bahariya and Farafra oases, negligible potential for harmful effects on soils and plants is anticipated. However, in case of using drip or sprinkler irrigation systems, the iron and manganese identified in groundwater may pre- cipitate, causing blockages to occur. The LAwaters salinity is found to be higher than NSA and above acceptable level for irrigation. Besides, salinity, chloride, and water sodicity make this water unsuitable for irrigation. Durov and piper diagrams reveal that the majority of investigated waters were calcium- magnesium sulfatewatertypecorrespondingtheBahariyaand Farafra, and sodium, chloride, and sulfate water type corresponding the Siwa, Bahrean, El-Gara, and Al-Jaghbub waters. The saturation indices for minerals indicated that most studiedLAwaterswereundersaturatedforhalite;however,the NSA waters were saturated with respect to aragonite, calcite, and dolomite.

Investigating the intelligence of the low-tech earth architecture of the Sahara: A feasibility study from the western desert of Egypt

Traditional building techniques such as earth construction have withstood the test of time. Its effectiveness and intelligence in responding to the socio-cultural and climatic context of many regions across the world have been well demonstrated. This article is concerned with the technical and social factors that led to the decline of this intelligent-architecture approach in the Sahara desert. The article investigates the potential and constraints of reintroducing earth construction architecture in four of the six western desert oases as case studies. These oases form the New Valley Governorate of Egypt: Baharia, Farafra, Al-Dakhla and Al-Kharja. Two field studies were undertaken. The first took place during a research trip that included Cairo, Giza, the four oases and Luxor, while the second was conducted in Al-Dakhla only. The results suggest a strong possibility for reusing earth architecture in the four oases from the environmental point of view. However, a number of limitations were identified—durability, buildability and the attractiveness of the mud architecture to the locals. Validation of the results and addressing those constraints are the focus of future work to assess the thermal performance of vernacular and modern case studies in the oases under investigation.

Springs in Egypt

Examples of springs in Egypt deal only with examples of natural springs producing potable water. None of the natural springs producing highly mineralized thermal water for therapeutical are considered. No water from natural springs in Egypt is bottled. Egyptian standards state that the total dissolved solids in potable water should not exceed 1000 ppm, except in Siwa, where the only available source for water for human consumption is from springs that have water containing more than 2000 ppm TDS. Six natural springs in Egypt provide typical examples for the Sinai and the Western Desert: Ain Furtaga in the southern pre-Cambrian province of Sinai Peninsula; Ain El Gudeirat in the sedimentary plateau of North Sinai; and Ain El Bishmo, Ain El Bousa, and Ain El Gabal in the Western Desert Oases of Bahariya, Kharga, and Dakhla. They discharge from the Nubian Sandstone aquifer system. The sixth spring, Ain El Arayes, is a spring in Siwa Oasis.

Evaluation of Environmental Isotopic and Salinar Composition of Groundwater in Oases of the Western Desert, Egypt

Abstract Representative water samples were collected from different oases in the western desert of Egypt to examine characteristics of Egyptian groundwater. Chemical data recognized two basic groundwater types; alkali bicarbonate and alkali chloride, where sodium has the highest concentration. For each region the median SD, δ18 0 and ionic strength of water calculated from their chemical analyses are recorded and plotted. Generally, the results of isotopic content measurements of the groundwaters from the different oases in the western desert indicate the fossile origin of these waters. The values of δD and δ18 0 of the western desert oases' waters are characteristic of old paleowaters from the Nubian sand aquifer. Modern sparse rainfall data suggest that any precipitation will exhibit moderate to large positive isotopic content enrichments and cannot be a source for these waters. They have been in no connection with the Nile water, moreover the change in isotopic composition is due to evaporation which is now ineffective at deeper levels.