Egyptian Red Sea Coast Research Articles

Crustal Structure in the Area of the Cannon Earthquakes of Abu Dabbab (Northern Red Sea, Egypt), from Seismic Tomography Inversion

Abstract Abu Dabbab seismogenic zone is located close to the Egyptian Red Sea coast. It is characterized by cannon earthquakes, long continued seismic activity, and frequent earthquake swarms. Earthquakes in this zone have occurred with high frequency over a long period of time in a confined linear zone that extends offshore in the Red Sea. A unique property is that earthquake signals can be heard by humans. Most previous studies suggested a magmatic origin for this activity. We perform a detailed earthquake tomography to image the crustal structure beneath Abu Dabbab and to explore the origin of its seismic activity and the cannon earthquakes. Based on the local and regional data, we construct a large‐scale seismic tomography model for the entire region and then enhance it for the local area of Abu Dabbab. We find the seismicity forms an arc‐shaped cluster that surrounds an aseismic block of high velocities and a low V P / V S ratio. According to the tomography results, we developed a new schematic geodynamic model proposing that the confined linear seismic zone in Abu Dabbab is due to the location of an active fault below a large, rigid, nondeformed block of Precambrian igneous rock, which reaches a depth of ∼10 km. The surface between this block and the moving parts of the fault are lubricated by fluids penetrating into the crust from the Red Sea as a result of combined strike‐slip and thrust displacements along the faults. These results reveal strong arguments for the tectonic origin of the seismicity associated with an important role of the fluid contents in Abu Dabbab area.

Distribution of soil organic carbon in the mangrove Avicennia marina (Forssk.) Vierh. along the Egyptian Red Sea Coast

The objectives of present study are: (1) to quantify the vertical distribution of the soil bulk density (SBD), soil organic carbon (SOC) content and SOC density in the soil of the mangrove forests in comparison with a reference site along the Egyptian Red Sea Coast; (2) to provide estimates of the carbon sequestration rate (CSR) and the carbon sequestration potential (CSP) of mangrove forests in Egypt; and (3) to establish a baseline data on SOC pools for future studies on SOC dynamics. Sampling was carried out in three stations along the Egyptian Red Sea Coast. The sampled station were classified to mangrove and reference (mud flat) stands. In each of the sampling station, five sampling sites were selected to assure representative samples to each of the mangrove and mud flat stands. Three soil cores were taken in each sampling site and were pooled together into one composite core per sampling site. In total, 120 soil samples were collected, i.e., one sample from each four soil layers (0–10, 10–20, 20–30 and 30–40 cm) at each of the 30 sampling sites (15 sampling sites per each of mangrove and mud flat stands). The mean distribution of SBD in the mangrove and mud flat stands increased significantly with depth. SOC content in the mangrove stands declined significantly with depth from 20.0 g C kg−1 at depth 0–10 cm to 11.4 g C kg−1 at depth 20–30 cm. SOC content in the mud flat stands declined significantly with depth from 9.0 g C kg−1 at depth 0–10 cm to 1.9 g C kg−1 at depth 30–40 cm. The stand type affected significantly the SOC pool, where the total mean of SOC pool of the mangrove stands (8.5 kg C m−2) was higher than that of the mud flat stands (2.6 kg C m−2). The average CSR of the mangrove stands (6.1 g C m−2 year−1) was higher than the mud flat stands (2.0 g C m−2 year−1). Based on the area of mangrove stands (525 km2) and CSR, the total CSP of mangroves in Egypt was 3.17 ± 0.05 Gg C year−1.

Assessment of Egypt’s Red Sea coastal sensitivity to climate change

A coastal sensitivity index (CSI) was developed to assess the response of the Red Sea coast in Egypt to climate change in terms of sea level rise and global warming. Six different variables pertaining to the intrinsic characteristics of the coast that extends to 1200 km were utilized, notably: coastal geomorphology, coastal slope, width of the coastal plain, shoreline exposure, fauna/flora and land use. Data have been extracted, manipulated and presented using remote sensing and GIS analysis. The resulting coastal sensitivity map depicts the susceptibility levels of the Red Sea coastal plain to climate change. The most severely sensitive segments (very high CSI) account for 31 % (365 km) of the coast. They occur across unconsolidated, flat, wide, exposed, ecologically effective and/or inhabited coasts. On the other hand, the least sensitive (low CSI) coastal segments total 245 km (20 %) and are mainly rocky, steep, narrow, barren and/or inaccessible shores. Eustatic sea level rise by 1 m should inundate a coastal area of 106 km2, whereas a sudden tsunami of 5 m height should overwhelm 724 km2, particularly at the southern section near Shalateen. Global warming of seawater should impact the coastal zone between Hurghada and Marsa Alam (270 km long) due to the occurrence of fringing coral reef systems. The coastal sensitivity index provides a synoptic overview that could help prioritize emergency plans and protection strategies to reduce the ramifications of climate change.

Environmental management and Egyptian tourism

This paper examines the growth of tourism and the subsequent issues related to environmental policy. Egypt has a substantial history of environmental policy but environmental degradation still occurs for a variety of reasons. This paper outlines the evolution of environmental policy in Egypt, and presents key limitations that hinder the implementation of these policies. These limitations are based on an examination of environmental policies that govern Red Sea tourism practice and development. These were determined by analysing laws and legislation, conducting in-depth, unstructured interviews with key informants, and through observation and recording along the Egyptian Red Sea coast. It was found that external and top-down initiation of environmental awareness, multiplicity of institutions and authorities, lack of a clear political voice for the environment, poorly-planned privatisation, and changing role of government impede the implementation of environmental policy.

Abundance and diversity of reef fish larvae in Mabahiss Bay, on the Egyptian Red Sea coast

Abundance and diversity of reef fish larvae in Mabahiss Bay, on the Egyptian Red Sea coast

Ultrastructure of the mouthparts and food habits of the Grapsid crab, Metopograpsus messor (Forskal, 1775) from different habitats of the Egyptian Red Sea Coasts.

Like all other decapods, the grapsid crab, Metopograpsus messor has mouth parts composed of six pairs of modified appendages. The present study revealed the structural significance of this complexity and the feeding habits of this species. Scanning electron microscope was used for examination of the mouth parts of the specimens collected from two different habitats. No differences were found neither in the structure of mouth parts nor in food analyses. The feeding habits showed that M. messor is opportunistic omnivore feeding on a wide variety of benthic organisms including algae, epifaunal animals as well as dead fish and other decayed animals in addition to higher plants particularly decomposed sea grass leaves and mangrove.

Spatial variation and environmental risk assessment of heavy metal in the surficial sediments along the Egyptian Red Sea coast

eight sites along the Egyptian Red Sea coast were investigated in order to evaluate the pollution status and environmental risk assessment of the study area. The results of the partitioning study showed that the average concentrations of the heavy metals analyzed in investigated sediment exhibited the following decreasing order Fe > Mn > Zn > Cr > Ni > Pb > Cu > Cd. The degree of surface sediment contamination was computed using Metal Pollution Index (MPI) and Geo-accumulation index (I geo). Metal Pollution Index showed that station 5 (Qusier Middle) suffered with metal pollutions. Association with adverse effects to marine organisms was determined using the classification of the sediments according to Sediment quality guidelines (SQGs). Sediment quality guidelines based on the consensus approach revealed that Pb and Cu had no adverse ecological effects.

Abundance and Diversity of Reef Fish Larvae in Mabahiss Bay , on the Egyptian Red Sea Coast

Abundance and Diversity of Reef Fish Larvae in Mabahiss Bay , on the Egyptian Red Sea Coast

The Roman and Islamic spice trade: New archaeological evidence

Ethnopharmacological relevanceTropical spices have long been utilized in traditional medicine and cuisine. New archaeological evidence highlights temporal changes in the nature and scale of the ancient spice trade and in the ancient usage of these plants. Furthermore, a study of their ‘materiality’ highlights that the impact of spices extends beyond their material properties. Here the botanical remains of spices recovered from archaeological excavations at a port active in the Roman and medieval Islamic spice trade are evaluated. Materials and methodsRecent excavations at Quseir al-Qadim, an ancient port located on the Red Sea coast of Egypt, have provided new evidence for the spice trade. Due to the arid conditions ancient botanical remains were preserved in abundance and these included spices, as well as a wide range of other food plants. Quseir al-Qadim was active as a transport hub during both the Roman and Islamic periods (ca. AD 1–250, known as Myos Hormos, and again during ca. AD 1050–1500, known as Kusayr), and the remains thus facilitate a study of temporal change in the trade and usage of these spices. Standard archaeobotanical methods were used to recover, identify and analyze these remains. ResultsAt least seven tropical spices were recovered from the excavations, as well as several other tropical imports, including black pepper (Piper nigrum), ginger (Zingiber officinale), cardamom (Elettaria cardamomum), turmeric (Curcuma sp.), fagara (cf. Tetradium ruticarpum), myrobalan (Terminalia bellirica and Terminalia chebula) and betelnut (Areca catechu). A marked contrast between the two chronological periods in the range of spices recovered points to changes in the nature and scale of the trade between the Roman and medieval Islamic periods, while differences in the contexts from which they were recovered help to identify temporal changes in the way in which the spices were utilized during those periods. ConclusionArchaeological and textual evidence suggest that in antiquity spices were used in ritual (funeral rites, offerings), in perfumery, and in medicinal remedies, with black pepper the only tropical spice regularly employed in cuisine. By the medieval period the culinary role of spices had grown significantly, both in the Middle East and in Europe, while retaining their importance in medicinal applications. In both time periods they were luxuries available only to the upper strata of society, but the material properties of spices and their elite status made them desirable to a wider section of society. In their pursuit of spices people became entangled in a meshwork of relationships, altered social realities and political power struggles. Globalization is one such entanglement, highlighting that the potency of spices goes far beyond their ability to stimulate our taste buds, delight our sense of smell and cure our ailments.

A New 8-Hydroxy Flavone O-Xyloside Sulfate and Antibacterial Activity from the Egyptian Seagrass Thalassia hemprichii

A new 8-hydroxy flavone O-xyloside sulfate, isoscutellarein 7-O-β-xyloside-2′′-O-sulfate, along with four known metabolites, were isolated and identified from seagrass, Thalassia hemprichii, collected from the Egyptian Red sea coast. The structures of the isolated compounds were established by chemical degradation and spectral analysis. The crude extract and the new compound displayed different potent antimicrobial activity against both Gram-positive and Gram-negative bacteria as well as fungi with MIC ranging from 0.1 to 10 μg/mL.

Egypt's Red Sea coast: phylogenetic analysis of cultured microbial consortia in industrialized sites.

The Red Sea possesses a unique geography, and its shores are rich in mangrove, macro-algal and coral reef ecosystems. Various sources of pollution affect Red Sea biota, including microbial life. We assessed the effects of industrialization on microbes along the Egyptian Red Sea coast at eight coastal sites and two lakes. The bacterial communities of sediment samples were analyzed using bacterial 16S rDNA pyrosequencing of V6-V4 hypervariable regions. The taxonomic assignment of 131,402 significant reads to major bacterial taxa revealed five main bacterial phyla dominating the sampled sites: Proteobacteria (68%), Firmicutes (13%), Fusobacteria (12%), Bacteriodetes (6%), and Spirochetes (0.03%). Further analysis revealed distinct bacterial consortia that primarily included (1) marine Vibrio spp.—suggesting a “marine Vibrio phenomenon”; (2) potential human pathogens; and (3) oil-degrading bacteria. We discuss two divergent microbial consortia that were sampled from Solar Lake West near Taba/Eilat and Saline Lake in Ras Muhammad; these consortia contained the highest abundance of human pathogens and no pathogens, respectively. Our results draw attention to the effects of industrialization on the Red Sea and suggest the need for further analysis to overcome the hazardous effects observed at the impacted sites.

A regional stratigraphic correlation for the upper Campanian phosphorites and associated rocks in Egypt and Jordan

Facies analyses and a sequence stratigraphical framework with regional correlation of the upper Campanian phosphate province are presented, based on three main sections located in Egypt (Gebel Duwi and Abu Tartur sections) and north Jordan (Umm Qais section). Fifteen facies types were grouped into: phosphate (FT1–5), carbonate (FT6–11) and siliciclastic (FT12–15) facies associations. The main component of phosphate rocks is pellets in situ and common reworked biogenic debris, especially in the upper phosphate beds (e.g. fish teeth and bones), which along with abundant Thalassinoides burrows suggests that the skeletal material was the main source for phosphates in Egypt; in contrast the common authigenic phosphatic grains (pristine) in Jordan reflect an upwelling regime. Based on age assignment as well as stratigraphical position, the phosphorite beds show great similarity that may suggests a similar origin and proximity during the period of deposition of the Duwi Formation of the Red Sea coast of Egypt and its equivalent, the Al-Hisa Phosphorite Formation in Jordan, which represents an early transgressive system tract of a depositional sequence. On the Abu Tartur plateau, the presence of sandy pyritic phosphatic grainstone (FT1) and glauconitic quartz arenite (FT12) in the middle part of the studied section, along with the absence of chert facies (FT14), reflects a more shallow marine depositional environment with increased fluvial sediment supply compared to those along the Red Sea coast and north Jordan.

Genetic barcoding confirms first breeding record of the Yellow Bittern, Ixobrychus sinensis, (Aves: Pelecaniformes, Ardeidae) in the Western Palearctic

We confirmed the first breeding record of the native Asian yellow bittern (Ixobrychus sinensis) in the Western Palearctic by genetic barcoding and morphometric analysis. In 2012 three small herons had been captured in Wadi Lahami at the western Red Sea coast of Egypt and these individuals had been tentatively determined as yellow bitterns. From blood samples of these birds we amplified and sequenced the barcoding marker (cytochrome-oxidase) and cytochrome-b and used sequences from own samples and further data inferred from GenBank for comparison. All three Egyptian specimens in question formed a monophyletic clade with sequences of I. sinensis and these were well separated from the sister species I. minutus in both phylogenetic reconstructions (p-distance, cytochrome-b: 9.6 %). A discriminant analysis based on six body-size parameters confirmed the assignment of these Egyptian specimens to I. sinensis. Along with this documentation we discuss phylogenetic relationships within Botaurinae and biogeographic aspects.

Pleistocene scleractinian corals from Marsa Alam area, Red Sea Coast, Egypt: systematics and biogeography

Coral reef terraces are investigated in five localities around Marsa Alam on the Egyptian Red Sea Coast. The reefal limestones and the alternating terrigenous clastics are assigned to the Pleistocene Samadai Formation. Sixty-one scleractinian coral species belonging to 25 genera and 10 families were identified. Thirteen scleractinian species, for the first time recorded from the Egyptian Red Sea coastal plain, are systematically studied. The stratigraphic distribution of these fossils is illustrated and discussed. Six species are extended to the Miocene and five other species are recorded from the Pliocene and still living in the present Red Sea and the Indo-Pacific. The geographic distributions of the identified coral species are illustrated on maps. These maps show that, all the identified coral species are distributed only throughout the Indo-Pacific realm, increasing from the central part westwards across the Indian Ocean to the Red Sea. There are four species that are restricted to the Red Sea, Arabian region and West Indian Ocean.

Zinc Oxide Doped Red Sea Egyptian Clay as a Varistor

Clay consists of about 50% SiO2 + 25% Al2O3 plus some other oxides with low abundance ratio like CaO, TiO2, Fe2O3, MgO and Mn2O3. Burning the clay at 700°C removes out the organic compounds and the mentioned oxides only remain. Our aim is to dope ZnO by the remaining oxides for varistors fabrication. Six types of clay were collected from Egyptian Red Sea Coast mines, after burning for 2 hrs the remaining oxides were mixed and ball milled with ZnO for 10 hrs according to the formula (100-Xn) ZnO +Xn, where n is the clay type and X is the ratio of the clay in grams, X takes the values 0.525 in 15 steps. Samples were pressed and sintered at three different temperatures (Tsin) 1200°C, 1300°C and 1400°C for 1 hr, and then studied via XRD, SEM, EDAX, J-E and C-V measurements. The obtained results were discussed in terms of the microstructure of the samples and the formation of Schottky barriers. Barrier height Ф, width W, interface state density Ns and donor state density Nd were calculated for the samples with highest nonlinearity α. It was found that the breakdown electric field Eo is related exponentially with the ratio of Zinc silicate phase whereas α scales with ratio of ZnO phase and the later increases linearly with Tsin. The electrical characteristics of the most promising sample were compared with those of ZnO samples doped pure SiO2 and Al2O3 obtained at the same preparation condition. This sample is comparable with the Japanese commercial varistor 5N220k Dc JVR.

The distribution of eared horse mussel, Modiolus auriculatus (KRAUSS, 1848) along the Red Sea coast of Egypt

A study on the ecology of the mussel Modiolus auriculatus that inhabits the inter-tidal rocky substrate of Hurghada area at the Red Sea coast of Egypt was carried out. A coastal survey had taken place during the period from February 2011 to January 2012; it covered the area between Ras Gharib (150km. North Hurghada City), of lat. 28° 21′ 43′′ and long. 33° 05′ 47′, and South El-Quseir of lat. 26° 05′ 53′′ and long. 34° 17′ 50′′. Eighteen sites were studied, and the surveyed species, M. auriculatus, was recorded in five stations out of those 18. The results of the survey also showed that the total number of individuals recorded at the station was 12,533 in five sites (Marine Biology station (NIOF), South El-Quseir, El-Quseir Harbor, North El-Quseir and Mangrove South Safaga); of which 12,133 of them were alive and 400 were dead. The examination of the field data sheets revealed that M. auriculatus was recorded at different types of habitats during the survey, and that each of these habitats had unique characters.

Flash Floods and Groundwater Recharge Potentials in Arid Land Alluvial Basins, Southern Red Sea Coast, Egypt

Flash flooding is one of the periodic geohazards in the southern Red Sea Coast. However, their freshwaters are the main source of recharging alluvial and fractured aquifers. This paper presents hydrological and geomorphologic classification of Wadi El-Gemal, Wadi Umm El-Abas, Wadi Abu Ghuson and Wadi Lahmi, along the southeastern Red Sea Coast in Egypt. The main goal is to find a relationship of flash floods and groundwater recharge potentials. Satellite imageries and topographic data were analysed via remote sensing and GIS techniques. The main four valleys’ orders range from six to seven. Wadi El-Gemal was the main focus of this study; it is characterized by high stream frequency, low stream density and coarse texture, reflecting influence of highly fractured Precambrian rocks. Most of the wadis have umbrella-shaped catchment areas, due to the influence of NW-SE Najd Fault System and late E-W strike-slip faults. The main wadis were divided into 45 sub-basins. 14 of the studied sub-basins flow into Wadi El-Gemal, 7 flow into Wadi Umm El-Abas, 10 are in Abu Ghuson, and rest of the basins flow into WadiLahmi. A conceptual model was used in this study, showing that most of the sub-basins have high flash flooding and low groundwater recharge potentials. However, only two sub-basins have low potential of flooding and high potential of groundwater recharge, whereas few sub-basins have moderate potential of groundwater recharge as well as flooding. For flash floods beneficiation and mitigation, construction of multifunctional embankment dams is imminent.

Comprehensive risk assessment of heavy metals in surface sediments along the Egyptian Red Sea coast

The contamination of heavy metals (Fe, Zn, Mn, Cu, Ni, Pb, Cd, Co, Cr, and Hg) in 16 surface sediment samples collected from the Suez Gulf, Aqaba Gulf and the Red Sea Proper was studied to evaluate their distribution and potential ecological risk. The concentrations of the studied metals decreased in the order of Fe>Mn>Zn>Cr>Ni>Co>Pb>Cu>Cd>Hg (3490.2, 115.77, 28.66, 18.47, 11.40, 9.70, 3.26, 1.94, 6.10, 0.02μg/g dry weight). Based on the effect-range classification (ERL–ERM, TEL–PEL, LEL–SEL), the studied heavy metals did not pose any environmental risks for all investigated stations except Marsa Alam and El-Quseir stations, which may pose an environmental risk for Cr and Ni. The ecological risk assessment for metals in surface sediments was evaluated using the metal pollution index (MPI), geoaccumulation index (Igeo), and potential ecological risk index (ERI). Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources.

Geotechnical Characteristics of Anhydrite/Gypsum Transformation in the Middle Miocene Evaporites, Red Sea Coast, Egypt

The Middle Miocene evaporites of Abu Dabbab Formation, north of Quseir City along the Red Sea coast of Egypt are composed mainly of thinly laminated, bedded and nodular anhydrite and microcrystalline gypsum especially in its lowermost part. Highly cracked inter-bedded clay, dolomite and stromatolite layers were recorded within the evaporite succession. The cracks in the inter-bedded clays are filled with evaporite materials indicating arid climatic conditions during exposure episodes. Swelling mechanisms in clay-evaporites include mechanical swelling due to hydration of clay minerals and transformation of the anhydrite into gypsum. Field observations as well as powder x-ray diffraction investigations have shown that anhydrite/gypsum modal ratio decreases gradually downward indicating that gypsum has transformed to anhydrite by solar heating. The clay minerals of the inter-bedded clay layers are dominated by smectite (46 %), illite–smectite mixed-layer (18 %), chlorite (13 %), palygorskite (9‘%), kaolinite (8 %), and illite (6 %). The liquid limit of the Abu Dabbab Formation (anhydrite and inter-bedded clays) is higher than 65 %, so considered as of very high swelling capabilities. Also, its swelling percentage was found to be (11–14 %), (28–35 %) and (58–65 %) for gypsum, clay and anhydrite, respectively. The swelling pressure was found to be (1.4–1.5 kg/cm2), (2.3–3.1 kg/cm2) and (4.7–5.1 kg/cm2) for gypsum, anhydrite and inter-bedded clay. The swelling pressure of gypsum is moderate and for both anhydrite and clay is high. The highly swelling capability of anhydrite and the inter-bedded clays causes geotechnical problems when got into contact with water. Alternating volume change due to phase transformation and solubility of calcium sulfate adds to the severity of problems associated with the host expansive clay strata.

Some Consideration on Overexploitation of Coral Reef Fish in Relation to Coral Reef Degradation in El-Tour, South Sinai, Egyptian Red Sea Coast

Some Consideration on Overexploitation of Coral Reef Fish in Relation to Coral Reef Degradation in El-Tour, South Sinai, Egyptian Red Sea Coast