Nubian Desert Research Articles

A craniometric study of the Medieval sample from Deraheib (Northern Sudan)

The history of North Africa has been always tightly connected to events occurring in Eurasia. Human migra-tions in both directions are well-documented in written sources and archaeological records. To gain a comprehen-sive understanding of historical processes, it is essential to study the remains of individuals who inhabited this region during various time periods. A lack of cranial metric data on the Medieval population of North Africa im-pedes thorough investigation of the population history of the region. This paper presents a craniometric study of the sample from the Southern necropolis at Deraheib. This study contributes to filling the existing void in the un-derstanding of the Medieval population of North Africa. According to written sources, the site was a center of gold mining, known as the city of al-Allaki, dated to the 9th to 15th centuries AD. The city attracted a diverse population seeking economic opportunities. Besides this, Al-Allaki served as an important point on the caravan route which was utilized by merchants and pilgrims traversing the Nubian Desert on their way to Jeddah. The study analyzes cranial metrics of a total of 23 individuals (14 male and 9 female) skulls recovered from the southern necropolis Deraheib sample and employs 55 linear dimensions, following Martin's/Howells craniometric protocol as well as some additional measurements. Statistical analyses were performed using the R language packages and the Multican software. Our results revealed heterogeneity of the sample in male and female parts of the sample at the intra-group level: an observation aligning with existing archaeological and historical evidence. The limited size of the sample warns against any firm conclusions regarding affinities of the Deraheib population. Our intergroup comparison has shown that the cranial sample from the Southern Necropolis of the Deraheib site displays morphological features that are more similar to neighboring Caucasoid populations rather than equatorial groups from East Africa.

Al‐Cu‐Fe alloys in the solar system: Going inside a Khatyrka‐like micrometeorite (KT01) from the Nubian Desert, Sudan

AbstractA recently described micrometeorite from the Nubian desert (Sudan) contains an exotic Al‐Cu‐Fe assemblage closely resembling that observed in the Khatyrka chondrite (Suttle et al., 2019; Science Reports 9:12426). We here extend previous investigations of the geochemical, mineralogical, and petrographic characteristics of the Sudan spherule by measuring oxygen isotope ratios in the silicate components and by nano‐scale transmission electron microscopy study of a focused ion beam foil that samples the contact between Al‐Cu alloys and silicates. O‐isotope work indicates an affinity to either OC or CR chondrites, while ruling out a CO or CM precursor. When combined with petrographic evidence we conclude that a CR chondrite parentage is the most likely origin for this micrometeorite. SEM and TEM studies reveal that the Al‐Cu alloys mainly consist of Al metal, stolperite (CuAl), and khatyrkite (CuAl2) together with inclusions in stolperite of a new nanometric, still unknown Al‐Cu phase with a likely nominal Cu3Al2 stoichiometry. At the interface between the alloy assemblage and the surrounding silicate, there is a thin layer (200 nm) of almost pure MgAl2O4 spinel along with well‐defined and almost perfectly spherical metallic droplets, predominantly iron in composition. The study yields additional evidence that Al‐Cu alloys, the likely precursors to quasicrystals in Khatyrka, occur naturally. Moreover, it implies the existence of multiple pathways leading to the association in reduced form of these two elements, one highly lithophile and the other strongly chalcophile.

Петроглифы Умм-Агаиба (Хукаб-Карара). По материалам Нубийской археологической экспедиции академии наук СССР. Часть 1. Племенные знаки

This article presents the research of petroglyphs discovered by Soviet archaeologists in 1962 and 1963 in course of epigraphic studies in Wadi al-Allaqi region within the framework of the archaeological expedition of the USSR Academy of Sciences. 200 hieroglyphic inscriptions were discovered in Umm-Agaib, copied and subsequently published. As for the petroglyphs, due to lack of time they were not reproduced and studied. However, the photos of the rocks in Umm-Agaib preserved in the archive of one of the expedition members, A.V. Vinogradov, allow us to make trace drawings of the petroglyphs, to study and publish them. Materials and methods. In this article we publish the so-called tribal brands (Arabic Wasm, pl. Wusum), used by the Bedouins of the Middle East (Iraq, Syria, the Arab Peninsula, Egypt, Sudan) primarily for branding camels. However, brands were also tribe symbols of sorts, and as such were often drawn on tents, clothing, or tattoos. Wasm was used by the Bedouins as a territorial marker, as well as to indicate caravan routes or the tribe’s migration. As such the brands were drawn on the rocks at the campsites. Results and discussion. This article attempts to determine the time period when tribal brands were drawn on the rocks of Umm-Agaib, as well as to answer the question of who could have left them: the Blemmyes who inhabited the Nubian desert in late Antiquity; the Arabs who migrated to the region of present-day Sudan in the 9th-11th centuries because of the active gold mining in Wadi al-Allaqi region and caravan trade that connected the Red Sea port of Aidhab with the Upper Egypt cities; or the Beja, indigenous inhabitants of the Nubian Desert. Conclusion. The author comes to the conclusion that at the current level of our knowledge of the brands left in the Nubian Desert, it’s impossible to accurately determine the time period when they were drawn. So far, we can talk about a wide time range from late Antiquity to the present.

Исследования Нубийской археолого-антропологической экспедиции НИИ и Музея антропологии МГУ в Центральном Атбае (2017–2022)

Materials and methods. This article is a collective research conducted by the members of the Nubian archaeological and anthropological expedition of the Research Institute and Museum of Anthropology of the Lomonosov Moscow State University. The article outlines the main results of the expedition's work over four field seasons at the Deraheib site, located at the headstream of Wadi al-Allaqi, in the northern part of the Nubian desert (Central Atbai) in the Republic of Sudan. From 2017 to 2022 The Nubian expedition excavated the Northern Fortress, Building 3 (Mosque) at the settlement of Deraheib, the Southern Necropolis; carried out an reconnaissance mission to the Onib ring structure. Results and discussion. Based on the study of the obtained archaeological materials (primarily the analysis of ceramics and textiles), as well as data from written sources, it was established that the medieval part of history of the monument covers the period between the 9th and 12th centuries. The archaeological site of Deraheib can be associated with the city of Al-Allaqi, mentioned in Arabic sources as a gold mining center in the Nubian desert, a trading city that was located on one of the caravan routes connecting the Red Sea port of Aidhab and the city of Aswan. The materials of the excavations of the Northern Fortress made it possible to advance a hypothesis that the building, erected in the 9th century, functioned more like a fortified castle of the local ruler rather than a fortress. The study of Building 3 allows us to say with confidence that it was a Friday mosque, founded at the beginning of the 10th century. Ongoing excavations in the Southern Necropolis have revealed Muslim burials (25 out of 31 investigated burials) and burials that are associated with the population that lived on the territory of Atbai in the Late Antique — Early Medieval period, known from classical sources as Blemmyes. A group of anthropologists obtained important data on the sex and age of the population of Deraheib, traces of daily activities and pathologies reflected in the skeleton. An important direction in the research of the MSU complex expedition is the study of the modern population of Central Atbai, primarily the Bisharin tribe of the Beja tribal union. The article outlines the main directions of these studies and preliminary results.

A cautionary signal from the Red Sea on the impact of increased dust activity on marine microbiota

BackgroundGlobal climate change together with growing desertification is leading to increased dust emissions to the atmosphere, drawing attention to possible impacts on marine ecosystems receiving dust deposition. Since microorganisms play important roles in maintaining marine homeostasis through nutrient cycling and carbon flow, detrimental changes in the composition of marine microbiota in response to increased dust input could negatively impact marine health, particularly so in seas located within the Global Dust Belt. Due to its strategic location between two deserts and unique characteristics, the Red Sea provides an attractive semi-enclosed “megacosm” to examine the impacts of large dust deposition on the vastly diverse microbiota in its exceptionally warm oligotrophic waters.ResultsWe used culture-independent metagenomic approaches to assess temporal changes in the Red Sea microbiota in response to two severe sandstorms, one originated in the Nubian Desert in the summer 2016 and a second one originated in the Libyan Desert in the spring 2017. Despite differences in sandstorm origin and meteorological conditions, both sandstorms shifted bacterial and Archaeal groups in a similar mode. In particular, the relative abundance of autotrophic bacteria declined while those of heterotrophic bacteria, particularly Bacteroidetes, and Archaea increased. The changes peaked within six days from the start of sandstorms, and the community recovered the original assemblage within one month.ConclusionOur results suggest that increased dust emission with expanding desertification could lead to undesirable impacts in ocean function, enhancing heterotrophic processes while reducing autotrophic ones, thereby affecting the marine food web in seas receiving dust deposition.

Строительные материалы в средневековой архитектуре археологического памятника Дерахейб (Судан)

The material for the article was samples of light gray rock with lighter and darker inclusions taken during the study of architectural structures of the archaeological site Deraheib (Sudan), which has been investigated since 2017 by the Nubian Archaeological and Anthropological Mission of the Research Institute and Museum of Anthropology of the Lomonosov Moscow State University (NAAM). This rock was used for making floor in Building 3 (Mosque) and as a bonding material in the walls of the Northern Fortress. Decorative architectural elements carved from the same rock were found during the study of the interior rooms of the Northern Fortress. Samples of this rock were taken into Russia by agreement with the National Corporation for Antiquities and Museums (NCAM) of the Republic of Sudan. The prepared thin sections were examined at the Research Institute and the Museum of Anthropology of the Lomonosov Moscow State University. Results. The analysis of thin sections showed that highly altered volcanic-metamorphic rocks, metamorphosed tuffs of acidic or alkaline composition, widespread in this region of Sudan, served as the material for pouring floors and for the making of a binder in the architectural structures of Deraheib, as well as for decorative architectural elements. Discussion. The conducted research indicates that the architects who erected buildings in Deraheib in the medieval period used locally available material, since it was very difficult to deliver building materials from the Nile Valley, taken into account the location of the monument almost in the center of the Nubian Desert. The tuff deposits at the site allowed the architects to build durable structures using local materials. The results of the study will allow to elaborate more accurate recommendations for the restoration of medieval architectural monuments of Deraheib.

Genetic Diversity and Population Structure of Medemia argun (Mart.) Wurttenb. ex H.Wendl. Based on Genome-Wide Markers

Medemia argun is a wild, dioecious palm, adapted to the harsh arid environment of the Nubian Desert in Sudan and southern Egypt. There is a concern about its conservation status, since little is known about its distribution, abundance, and genetic variation. M. argun grows on the floodplains of seasonal rivers (wadis). The continuing loss of suitable habitats in the Nubian Desert is threatening the survival of this species. We analyzed the genetic diversity, population genetic structure, and occurrence of M. argun populations to foster the development of conservation strategies for M. argun. Genotyping-by-sequencing (GBS) analyses were performed using a whole-genome profiling service. We found an overall low genetic diversity and moderate genetic structuring based on 40 single-nucleotide polymorphisms (SNPs) and 9,866 SilicoDArT markers. The expected heterozygosity of the total population (HT) equaled 0.036 and 0.127, and genetic differentiation among populations/groups (FST) was 0.052 and 0.092, based on SNP and SilicoDArT markers, respectively. Bayesian clustering analyses defined five genetic clusters that did not display any ancestral gene flow among each other. Based on SilicoDArT markers, the results of the analysis of molecular variance (AMOVA) confirmed the previously observed genetic differentiation among generation groups (23%; p < 0.01). Pairwise FST values indicated a genetic gap between old and young individuals. The observed low genetic diversity and its loss among generation groups, even under the detected high gene flow, show genetically vulnerable M. argun populations in the Nubian Desert in Sudan. To enrich and maintain genetic variability in these populations, conservation plans are required, including collection of seed material from genetically diverse populations and development of ex situ gene banks.

AEOLIAN SANDS IN NORTH AFRICA AND THE SOUTHWEST OF THE ARABIAN PENINSULA

Background. The majority of the world’s deserts were formed within the valleys and coasts of ancient alluvial rivers and lakes. The material carried across many hundreds and thousands of kilometres by the wind was mixing with sediments of various genetic types. In addition, due to the similar physical nature of the wind and water transport of sediments, the recognition of the aeolian environment can be problematic. Aim. Using innovative research approaches, to provide a qualitative structural description of sands; to identify and characterize factors contributing to the formation and preservation of a ferruginous film on grains; to establish the genesis of the transferred sediments, as well as the relationship with the parent rocks. Materials and methods. Samples for analysis were collected from aeolian deposits in three deserts: Rub al Khali (United Arab Emirates), Nubian desert (Egypt) and Grand Erg Oriental (Algeria). Particle size analysis was used to characterize samples in terms of three parameters (length, width, thickness). X-ray diffraction analysis was carried out using an ARL X’tra diffractometer (Switzerland). The collected samples were also studied using a binocular microscope in reflected light and a scanning electron microscope. Results. The mineral composition of the sands under study was examined. The graphs (histograms) of the size distribution of quartz grains (being the most common sand mineral in terms of size and frequency of occurrence) were plotted. The shape and nature of the grain surface were analysed. Conclusion. The frosting on aeolian sand grains can result not only from micro-cracking as the most common sign of wind transfer, but also from the presence of a calcite film on grains. Factors contributing to the formation and preservation of a ferruginous film (desert varnish) were identified. The conditions for the formation of aeolian sands, as well as the genesis of such sand sediments, were established.

How diamonds embedded in meteorites could offer a glimpse into the mantle of Mars

On October 7, 2008, a 13-foot-long asteroid burst through Earth’s atmosphere and exploded above Sudan’s Nubian Desert. Its arrival created a stir because it was the first time that an asteroid that had been tracked and studied in space had collided with our planet. Even more intriguing, the bulk of the fragments that landed on Earth, collectively referred to as Almahata Sitta—the Arabic name of the train station near their landing site—turned out to be carbon-rich meteorites containing graphite and diamonds. As it descended to Earth, the asteroid known as 2008 TC3 left this contrail, captured by a cellphone camera. The asteroid’s scattered fragments and their composition have been the subject of intense study. Image credit: Mohamed Elhassan Abdelatif Mahir (Noub NGO), Dr. Muawia H. Shaddad (Univ. Khartoum), and Dr. Peter Jenniskens (SETI Institute/NASA Ames). Such meteorites are called ureilites, and they usually contain tiny diamonds about 100 to 1,000 nanometers long. But a few of the Almahata Sitta meteorites had diamonds up to 100 times larger (1). “It was kind of an unusual sample,” says Meenakshi Wadhwa, director of the Center for Meteorite Studies at Arizona State University (ASU) in Tempe. It was thought that diamonds in ureilites formed when a massive asteroid collided with a planet, with the planet destroyed in the collision. The ensuing high temperatures and pressures would have turned the asteroid’s graphite into diamond. But a new theory suggests that the Almahata Sitta ureilites may have come from material ejected from Mars when it was barely a few million years old. If so, the meteorites and the diamonds in them could be giving us our first glimpse of the interior of another planet besides Earth. The Almahata Sitta diamonds pose many puzzles. First, they are so large that scientists have recently begun to question …

Meteorites hint at crowded early solar system

Tiny diamonds from a rare type of meteorite are evidence for a lost planet between the size of Mercury and Mars, according to new research (Nat. Commun. 2018, DOI: 10.1038/s41467-018-03808-6). The findings support a proposed picture of a crowded early solar system where collisions between planetlike bodies were common. In 2008, a car-sized asteroid exploded over Sudan, scattering meteorites known as Almahata Sitta across the Nubian Desert. Many of the meteorites belong to an unusual class called ureilites thought to come from a single, long-since-destroyed body in our solar system referred to as the ureilite planetary body (UPB). Ureilites contain a mix of iron and magnesium silicate minerals along with graphite and small diamonds. Scientists previously hypothesized three ways diamonds in ureilites could form: The shock that demolished the UPB could have transformed graphite into diamond; vapor deposition of hydrocarbon gases could have produced the minerals; or they could have

Genetic profiling of the critically endangered palm species Medemia argun using newly developed chloroplast DNA markers

ABSTRACTBackground: Medemia argun is a rare wild palm tree species. Its global existence is assumed to include the main population of about 1000 trees in the Nubian Desert of Sudan and some scattered individuals in southern Egypt. The species had previously been assumed to be extinct, but then reported to be extant about 20 years ago.Aims: To assess genetic variation and explore population genetic structure of M. argun, through development and analysis of microsatellite markers.Methods: The genome sequence mining approach was applied in order to identify microsatellites in the chloroplast genome of Bismarckia nobilis, a species closely related of M. argun. A set of 49 markers were designed, and their characteristics are now provided. Seven chloroplast DNA markers were developed for use in the genetic characterisation of this threatened species.Results: Five markers were found polymorphic in M. argun, which enabled the assessment of the genetic diversity of the species. Significant genetic differentiation was observed among generations and collection sites, accompanied by low genetic variation. The seven markers developed were polymorphic among the wild relatives Hyphaene thebaica and Borassus aethiopum.Conclusions: This is the first study to report molecular markers for M. argun. Our results suggest that the genetic consequences of population fragmentation in M. argun are beginning to be evident.

Fast characterization of C-glycoside acetophenones in Medemia argun male racemes (an Ancient Egyptian palm) using LC-MS analyses and computational study with their antioxidant effect

Medemia argun is an ancient endemic palm growing in Nubian Desert of Egypt and Sudan. Liquid chromatography coupled with mass spectrometry in negative ion mode (LC/ESI-MS) has proved to be a potent tool for rapid identification and characterization of complex phytochemicals in male racemes of M. argun. A total of seven compounds were tentatively identified comprising of two C-glycoside acetophenones, along with the known compounds one stilbene derivative and four known flavonol derivatives from 40% methanolic portion. The product ions of acetophenone derivatives [M−H]– were shown to be cross-ring cleavages of the hexoside moiety [M-(90/120)-H]– characteristic for C-glycoside linkage. The position of CC-linkage was elucidated by DFT study using the Fukui functions and descriptors. The results revealed that hexose was conjugated with aglycones at C3 or C5. In addition, the theoretical antioxidant activity of compounds 6 and 7 was evaluated by using Bond Dissociation Enthalpy (BDE).

Infrasound detection of meteors

Meteorites that penetrate the atmosphere generate infrasound waves of very low frequency content. These waves can be detected even at large distances. In this study, we analyzed the infrasound waves produced by three meteors.The October 7, 2008 TC3 meteor fell over the north Sudan Nubian Desert, the February 15, 2013 Russian fireball, and the February 6, 2016 Atlantic meteor near to the Brazil coast.The signals of these three meteors were detected by the infrasound sensors of the International Monitoring System (IMS) of the Comprehensive Test Ban Treaty Organization (CTBTO). The progressive Multi Channel Technique is applied to the signals in order to locate these infrasound sources. Correlation of the recorded signals in the collocated elements of each array enables to calculate the delays at the different array element relative to a reference one as a way to estimate the azimuth and velocity of the coming infrasound signals. The meteorite infrasound signals show a sudden change in pressure with azimuth due to its track variation at different heights in the atmosphere. Due to movement of the source, a change in azimuth with time occurs. Our deduced locations correlate well with those obtained from the catalogues of the IDC of the CTBTO.

Phenolic Compounds from the Fruits of Medemia argun, a Food and Medicinal Plant of Ancient Egypt

Medemia argun is a mysterious and little known monotypic fan palm from the Nubian Desert Oases of southern Egypt and northern Sudan. Its fruits have been found in the tombs from the 5th Dynasty (ca. 2500 BC) to Roman times (6-7th century AD), including the celebrated tomb of Tutankhamun. In ancient Egypt, the fruits of this palm were widely distributed and were highly valued, as confirmed by their frequent occurrence in offerings in the tombs. In order to elucidate the chemical composition of the phenolic fraction, phytochemical investigation of the BuOH extract of fruits was carried out to afford eight compounds (1-8), among which was the new 2,4-dihydroxy-6-methylacetophenone 2-0-β-D-glucopyranoside (1). With the aim to investigate if the high shelf life of M argun fruits could be related to the occurrence of antioxidant principles that were able to prevent oxidative reactions, the evaluation was carried out of the in vitro antioxidant activity by Trolox equivalent antioxidant capacity (TEAC) assay of the extract and isolated compounds.

The Contribution of Environmental Impact Assessment Studies to the Flora Biodiversity in Sudan

Environmental Impact Assessment Studies (EIA) for four developmental projects were chosen for this study viz-a-viz., oil and gas, river diversion, hydropower and gold mining. The EIA studies for these activities have been conducted in three different ecological regions: the flood region in the former southern Sudan, low rainfall Savannah and desert region. Trees, shrubs and herbaceous species were identified and recorded in each region. Species encountered for the first time, endangered, invasive and increasers were also reported. The EIA studies have produced lists of natural flora in areas which were difficult to access without the EIA missions. During the EIA study for Jonglei Canal project the new mono specific genus Suddia sagitifolia was discovered in the flood region as the only endemic aquatic plant in Sudan. Within the same region, the smallest floating plant in Sudan (Wollfia hyaline) was reported. The critically endangered “Argon Palm” (Medemia argun) was encountered in the Nubian Desert of the Red Sea State during a gold mining EIA study. The Seha (Belpharis persica), not reported to exist in desert conditions, has been found in the Great Desert west of the Nile during an EIA study for Kajbar Hydropower project. The paper calls for the publication of the above findings and highlights the need for further detailed studies in order to enhance knowledge of the Sudanese biodiversity status.

Neoproterozoic metamorphic events along the eastern margin of the East Sahara Ghost Craton at Sabaloka and Bayuda, Sudan: Petrology and texturally controlled in-situ monazite dating

Recent geodynamic models for the evolution of the East Sahara Ghost Craton (ESGC) propose delamination of the subcontinental lithospheric mantle due to the formation of Pan-African orogenic belts along its margins. To identify the behavior of the craton's basement during the Neoproterozoic we studied metapelitic rocks from the eastern margin of the craton at Sabaloka and Bayuda, both of which lie about 230km apart along the boundary with the Arabian-Nubian Shield and are considered to be parts of the ESGC. The results are compared to those published for the central part of the craton at Uweinat for a better understanding of the Neoproterozoic tectonic evolution of the craton as a whole.Petrology and texturally controlled in-situ monazite dating reveals that the Sabaloka granulites and the Bayuda metasediments experienced two different metamorphic events. The events at Sabaloka and Bayuda are neither synchronous nor similar in intensity and/or nature, with the events in Bayuda being older than those in Sabaloka and also of lower intensity. At Sabaloka, monazite inclusions in garnet record the timing of an early Neoproterozoic high temperature crustal thickening event at 780–720Ma, while monazite grains in coarse-grained cordierite–spinel symplectites indicate the timing of a Neoproterozoic high to ultra-high temperature overprint at ∼602Ma. Applying the same approach of monazite dating to the pelitic schists from the Dam El Tor fold-and-thrust-belt in the Kurmut Terrane at Bayuda, a crustal thickening event leading to amphibolite-facies metamorphism is dated at ∼890Ma. It was followed by low-grade metamorphism at ∼670Ma leading to recrystallization of matrix minerals. This study thus indicates that the nature and timing of Neoproterozoic tectonometamorphic events along the eastern margin of the ESGC were heterogeneous, both temporally and in their intensity. The ∼890Ma age obtained from the Kurmut Terrane metasediment provides, for the first time, a direct age of the amphibolite-facies metamorphism, slightly later than the magmatism during the Bayudian event dated at 920–900Ma in the Rahaba-Absol Terrane. We infer that tectonism in the juvenile oceanic arc and ophiolitic terranes of the Arabian Nubian Shield (ANS) in the east triggered the end of the passive margin stage of the ESGC and led to the subduction related magmatic–metamorphic Bayudian event. The passive margin stage of the craton further south at Sabaloka seems to have ended later at around 780–720Ma, which may have caused the first high temperature crustal thickening event there. Published magmatic formation ages of 810–806Ma from basalts and ophiolites indicate a rifting stage that formed oceanic re-entrants in the Bayuda and Nubian desert areas along the margin of the craton, subsequent to the Bayudian event. After collision with some of the eastern juvenile ANS terranes the oceanic re-entrants were closed, causing magmatism and a low-grade metamorphic overprint on the amphibolite-facies rocks dated here at ∼670Ma. At Sabaloka, the high-T to UHT granulite-facies decompression event at ∼602Ma and the widespread granitic magmatism all along the eastern margin between 650 and 570Ma was most likely due to the final collision of the ESGC and the ANS. The heterogeneity of Neoproterozoic tectonometamorphic events along the eastern margin of the ESGC thus indicates a local tectonic control on these metamorphic events.In contrast to the eastern margin, no evidence for a metamorphic event during the Neoproterozoic has been found in the center of the craton at Uweinat. The granulites at Uweinat record a Neorchean UHT metamorphism and a Paleoproterozoic UHT reworking. Therefore, it is more likely that the proposed delamination of the subcontinental lithospheric mantle of the entire ESGC was not synchronous and was caused by different orogenic events in different parts of the craton.

The impact of Merowe Dam on Simulium hamedense vector of onchocerciasis in Abu Hamed focus - Northern Sudan

BackgroundAbu Hamed, the northernmost onchocerciasis focus in the world, is located along the River Nile banks in the Nubian Desert. Hydroelectric dams can alter activity of black flies and may provide breeding sites for black fly. Merowe Dam, the largest hydropower project in Africa, was built west of Abu Hamed focus in 2009. The impact of the Dam on onchocerciasis and its black fly vectors in Abu Hamed focus was measured in this study.FindingsEntomological surveys for aquatic stages and adult Simulium hamedense were conducted before and after the inception of Merowe Dam in 2007/2008 and 2010/2011. There was no black fly breeding or adult activity in the previously known breeding sites upstream of the Merowe Dam with the western most breeding site found in AlSarsaf village near the center of the focus. No adult or aquatic stages of black flies were found downstream of the Dam.ConclusionsThe artificial lake of the Dam flooded all the breeding sites in the western region of the focus and no aquatic stages and/or adult black fly activity were established in the study area upstream of the Dam. The Dam seems to have positive impact on onchocerciasis and its black fly vectors in Abu Hamed focus. These outcomes of the Merowe Dam might have contributed to the recently declared interruption of onchocerciasis transmission in Abu Hamed focus. Continuous entomological surveys are needed to monitor presence of black fly vectors and its impact on the disease.

The Design of the Nubian Desert

The Design of the Nubian Desert

Variations in bird communities of the Saharan mountains

Characteristics and variations of the bird communities in the Saharan mountains were evaluated in five massifs from West to East: the Adrar of Mauritania, the Ahaggar in Algeria, the Adrar of the Iforas in north-eastern Mali, the Aïr Mountains in northern Niger, and the Red Sea Mountains in the Eastern Desert of Egypt. Bird censuses (n = 110) were conducted during dry seasons. A total of 139 species were recorded, of which 120 remained after elimination of occasional visitors and were used for analysis. Total richness and diversity increased from the most central and high Ahaggar towards the western, eastern and especially southern massifs. Among the resident communities the number of Saharo-Sindian species was higher in the central, eastern and western massifs, whereas Afrotropical species were more abundant in the southern ones. A principal component analysis distinguished three opposite poles of species linked with Adrar of the Iforas, Aïr and Red Sea mountains and cluster analysis led to the ordination of the five massifs along a longitudinal gradient from West to East. Avifaunal variations between the different Saharan mountains sampled led to a regional pattern in relation with faunistic affinities and it fitted with the three biogeographical subregions of the Saharan biome: Sahara, Sahel and Nubian Desert.

Characterization of barren, granitic soils from the Nubian Desert (SW Egypt) by 57Fe Mössbauer spectroscopy

Abstract 57Fe Mössbauer spectroscopy - a versatile technique involving the recoil-free, resonant absorption and emission of nuclear gamma (γ) rays by the iron-57 isotope in natural iron in solids - has been used to provide quantitative information about the mineral host, occupation sites and oxidation states of iron atoms in geological samples. This technique has been applied to the bulk chemistry of a barren soil (Soil A) derived from an aluminous-type granite and another barren soil (Soil B) derived from a sodic-type granite located ~ 100 kilometers apart in the Nubian Deseit in the currently hyper arid south-west of Egypt and which exhibit distinct chemical and mineral differences. The analyses indicate different mineral hosts for the iron in these samples, namely, vermiculite-chlorite plus some hematite in Soil A and hematite and goethite plus minor aegirines in Soil B. Each soil has distinct intensities of oxidized iron (89% for Soil A and 100% for Soil B) and these differences reflect changes in soil sources and processes.