Egyptian Red Sea Research Articles

Antimicrobial activity of some fungal isolates from Red Sea in Egypt

The study investigates the antimicrobial efficiency of fungi from the Red Sea in El-Quseir and Sharm El-Sheikh districts. The fungi’s active metabolites were tested for their antibacterial activity against pathogenic germs. The fungi were grown on nutritional agar media and malt extract agar medium. The extracts of marine fungi were also investigated for their cell death potential, using lung carcinoma cells as a cell line. The results of our study demonstrated the strong antimicrobial activity of marine fungi towards both Gramme positive and Gramme negative microorganisms, particularly against Serratia marcenscens and Salmonella. The ethyl acetate extract from El-Quseir (a sand source) and Sharm El-Sheikh (a water source) demonstrated the highest inhibition zones, measuring 37 mm and 35 mm, respectively. The normal cell line (MRC-5) was subjected to cytotoxic effects that demonstrated antibacterial and anticancer properties, while also exerting non-significant toxicity on active concentrations. Comparing petroleum ether, chloroformic, and methanolic extracts to ethyl acetate extract, and our results showed that the latter had the lowest antibacterial activity. Against medically used lung cancer cell lines, marine fungi shown antitumor activity.

Using ISSR markers to detect genetic variation for marine turtles populations in Egypt loggerhead (Caretta caretta) and green turtles (Chelonia mydas)

In Egypt, along the Mediterranean coast, the loggerhead (Caretta caretta) and green (Chelonia mydas) come during nesting season to lay their eggs or for food with a rare occurrence for the leatherback turtle (Dermochelys coriacea). In the Egyptian Red Sea there are five species that come to visit, the most common to observe are hawksbill (Eretmochelys imbricata) and green (Chelonia mydas). The goal of this study is to conduct some genetic and ecological analyses a) to generate new markers that include other segments of marine turtles’ genome, as a tool to investigate new areas of variation/polymorphism between, among, and within populations and individuals; b) determine genetic diversity between and within the Mediterranean and the Red Sea populations using (individuals from the same and different habitats using ISSR); and c) determine allele frequency. At the ecological level, this study aims to assess sea turtles' habitat and population distribution among different habitats in Egypt. Throughout the duration of this study, it was noted that there was a decrease in nesting areas attributable to the loss and fragmentation of habitats. Although there are some areas with no significant nesting prosperities it considered significant areas for foraging and highly important as migratory corridors, especially in the Mediterranean. The massive urbanization and unplanned touristic developments affect sea turtle habitat over the Egyptian Mediterranean coast. The Mediterranean coast showed demographic changes in the coastal regions. On the other hand, areas could still be valued with significant nesting areas for sea turtles, but an intense and regular monitoring programme should be established. The Red Sea needs a regular monitoring programme for better management conservation measures to be adopted. The polymorphism percentage resulting from ISSR marker was 45 and 36 for both loggerhead and green turtle populations in the Mediterranean, respectively; and 69 for the green turtle populations in the Red Sea.

Comparison of Chemical Composition and Bioactivities of Polysaccharides of Brown Seaweeds, the Red Sea, Egypt, Hurghada

Sulfated polysaccharides (SPs) from algae have been shown to be effective in a number of biological applications. Therefore, the chemical composition and different biological functions of various SPs were determined for three brown seaweed species from the Egyptian Red Sea: <i>Dictyopteris polypodioides, Polycladia myrica</i>, and <i>Turbinaria decurrens</i>. It has been found that the yield of crude SPs was higher than that of alginate and fucoidan with a range of 43.64% to 61.90%. Fucoidan, which has the maximum carbohydrate content of 56.89%, was found in <i>D. polypodioides.</i> The crude SPs of <i>P. myrica </i>had the greatest sulfate content of 22.44%. All functional groups of the examined samples were confirmed by the Fourier Transform Infrared spectrum (FTIR). Experimentally, three applicable assays were used to quantify the antioxidant activity of the extracted SPs depending on the method used, the type of polysaccharides, and algal species. The anti-diabetic activity of <i>T. decurrens</i>-crude SPs was highly active scoring 85.85% in the α-glucosidase assay. The anti-obesity activity showed the highest value (95.25%) for <i>T. decurrens</i>-fucoidan. Besides, <i>T. decurrens</i>-crude SPs showed the highest anti-arthritic activity (89.89%). In addition, a few positive records of antibacterial activity were detected. Furthermore, the most potent <i>T. decurrens</i>-crude SPs extract was tested for cytotoxicity against human liver cells and found to be safe. The activity of the isolated SPs and their chemical composition were shown to be correlated. Conclusively, the bioactivities recorded herein by the tested SPs pose promising medicinal applications towards developing a new therapeutic intervention.

Statistical Downscaling of Surface Air Temperature Projection over the Egyptian Red Sea Coast

Statistical Downscaling of Surface Air Temperature Projection over the Egyptian Red Sea Coast

Harnessing solar and wind power for sustainable seawater desalination: A multi-criteria geospatial suitability analysis

Water and energy sustainability are major concerns of the world's nations at present. This research introduces a geographical decision-making model for strategically selecting optimal locations for seawater reverse-osmosis desalination plants (SWRODPs). Furthermore, it assesses the best electrification approach, considering onshore wind turbine (WT) or solar photovoltaic (PV) power plants. A representative case-study of the Egyptian Red Sea Coast Region (ERSCR) is considered to validate the proposed model. The study delineates nineteen assessment criteria for building an informed selection of SWRODPs' potential locations. Seven experts with at least ten years of expertise in desalination and renewable technologies were selected to obtain accurate assessment criteria that imitate the real-life selection process. The group best-worth method (GBWM) was employed to ascertain optimal weights for the geospatial model criteria. The findings indicate that a mere 6.11 % of the total land area is deemed suitable, with the remaining 93.89 % classified as restricted. The suitable area is divided into different suitability classes in which about 65.85 % of the suitable area is found good for establishing the SWRODPs, while about 23.65 % of suitable land is found of moderate suitability. Besides, about 9.21 % and 0.03 % of suitable lands are considered very good and excellent suitability for implementing SWRODPs' projects. Moreover, the analysis pinpointed 8 % of the ERSCR (∼12,810 km2) as a highly suitable area for PV installation, predominantly within Qusir, Ras Sidr, Hurghada, and Ataqa districts. Concurrently, a scant 0.15 % (∼244 km2) is optimal for WT in the Qusir district. Further, the results offer proposals to the authorities and energy investors with about 50,200 km2 and 39,858 km2 of the ERSCR suitable for establishing SWRODPs powered by PV and WT, respectively. Overall, the research findings are anticipated to bolster the UN's sustainable development goals 6 and 7 and align with Egypt's Vision 2030.

Biochemical identification of some true halophytes using DNA Barcoding in the Egyptian Red Sea coast

Biochemical identification of some true halophytes using DNA Barcoding in the Egyptian Red Sea coast

The role of the Red Sea rift and the inherited geological structures in the seismo-volcanic activity along the rift flanks

The role of the Red Sea rift on the development and the discrepancy of the seismo-volcanic activity along its flanks is still a debate. Here we tried to resolve this debate by a high-resolution tomographic imaging of the northern Red Sea subsurface structures. For the first time, a large number of arrival time data from the Saudi and Egyptian seismic networks were used. The area comprises the Lunayyir volcanic field in the Saudi Arabia, the Abu-Dabbab seismogenic zone in the Egyptian Red Sea coast, and the Zabargad Shear Zone in the Red Sea. This study revealed clear images of the Red Sea rift-related structures along its flanks. The subsurface extension of the different shear and suture zones existing in the Arabian Nubian shield are well imaged. It is found that the Lunayyir seismo-volcanic activity is possibly controlled by the reactivation of the Yanbu suture zone that is associated with steeply northwestward dipping structure. The suture detachments were observed and identified across the Red Sea as low-V channels. The Egyptian Eastern Desert is found to be highly deformed with crustal-scaled low-V structures which were inherited from the early period of Gondwana collision. The NE-SW strike slip faults along the Red Sea were found to be a part of this deformation that are extended deeply in the crust. The Abu-Dabbab and Marsa-Alam areas were strongly influenced by this deformation with possible magma intrusions. This study provides new insights on the role of the Red Sea in the seismo-volcanic activity along its flanks.

Occurrence of trace elements in coastal seawater of the Egyptian Red Sea

Occurrence of trace elements in coastal seawater of the Egyptian Red Sea

Elemental composition and metal pollution in Egyptian Red Sea mangrove sediments: Characterization and origin

The present work was conducted to characterize the mangrove sediments along the Egyptian Red Sea in terms of elemental composition and to assess the extent of pollution and its sources. A total of 26 samples of mangrove sediments were collected from three different areas: Sharm El Madfea, Sowmaa Mangrove and Abu Fasi. The samples were analyzed using the inductively coupled plasma – mass spectrometry ICP–MS and atomic-emission spectrometry ICP-AES. Mass fractions of a total of 58 major and trace elements were determined in the mangrove samples. Univariate and multivariate statistical analyses were performed to determine the origin of trace and major elements in the mangrove sediments. The normalized values show that the elements above the background can be indicated in descending order as follows: P > Cd > Sr > Ca > U > Se > As > Sn > Cu > Sb > Pb > Mo > Ag. Several pollution indices were also calculated. Principal component analysis revealed three clusters of the studied sediment samples. The analysis of the ratio indicators shows that the origin of the sediments mostly falls near continental island arcs (CIA). The pollution indices show remarkable pollution levels and enriched elements. The data obtained can serve as baseline data for the sediments of the mangrove environment and can be used to study possible changes in the future.

Sunscreens and micro(nano)plastics: Are we aware of these threats to the Egyptian coral reefs?

During a snorkeling trip to Marsa Alam and Hamata (southern Red Sea Riviera, Egypt) I explored the coral reefs and the diverse marine habitats of fish and invertebrate species. The area invites recreational diving and snorkeling, but the beaches are littered with all sorts of solid waste (mainly fragmented plastics). Also, there are no local restrictions on sunscreen use. The development of tourism to the area raises questions about the environmental impact and how its further growth will have on coral reefs. Every year, 1.2 million tourists visit the Red Sea coast (about 3287 tourists per day) and release about 1.7 tons/month of sunscreen into the Red Sea. As an ecologist and editorial board member of Science of the Total Environment, I ask myself how we as scientists can increase public awareness and call for prompt actions to protect the coral reefs. The discussion underlines two major threats to the Egyptian coral reefs: sunscreen use and micro(nano)plastics waste. The discussion closes with possible solutions, future perspectives, and recommendations to protect the coral reefs ecosystem of the Egyptian Red Sea.

Flash Flood Hazard Assessment along the Red Sea Coast Using Remote Sensing and GIS Techniques

The Egyptian Red Sea coast is periodically exposed to flash floods that cause severe human and economic losses. That is due to its hydro-geomorphological characteristics. Therefore, identifying flash flood hazards in these areas is critically important. This research uses an integrated approach of remote sensing data and GIS techniques to assess flash flood hazards based on morphometric measurements. There are 12 drainage basins in the study area. These basins differ in their morphometric characteristics, and their main streams range between the 4th and 7th order. The morphometric parameter analysis indicates that three wadis are highly prone to flooding, five wadis are classified as moderate hazard, and four wadis are rated under low probability of flooding. The study area has a probability offlooding, which could cause serious environmental hazards. To protect the region from flash flood hazards and the great benefit of rainwater, the study recommended detention, crossing, diversion, and/or storage of the accumulated rainwater by building a number of dams or culverts along the main streams of wadis to minimize the flooding flow.

Evaluation of trace elements concentration using sediments and mussels as bioindicators and pollution indices in the Egyptian Red Sea

The current work was designed to evaluate the pollution status of the coastline region of the Egyptian Red Sea through monitoring the trace elements in sediments and mussels (Brachidontes variabilis and Modiolus auriculatus) that sampled during winter and summer 2019 from nineteen stations along the investigated area. The analyzed elements showed an annual mean of 20.21, 2.08, 4.79, 46.41, 11.35, 18.14, 128.93 and 12,520.07 μg/g (sediments), 1.02, 0.39, 3.35, 23.73, 0.59, 1.14, 1.43 and 81.94 μg/g (B. variabilis) and 1.39, 0.47, 1.70, 24.69, 0.77, 1.66, 2.16 and 119.80 μg/g (M. auriculatus) for Pb, Cd, Cu, Zn, Co, Ni, Mn and Fe, respectively. The summer recorded highest values of all studied elements in the mussels' species with significant temporal variations (p < 0.05) for the most investigated elements. The pollution indices like CF, PLI, MPI, Igeo and EF were calculated to evaluate the elements contamination degree in the examined areas.

A new species of Trimma of the T. taylori species group (Teleostei: Gobiidae) from the Red Sea, Indian Ocean.

A new species of Trimma is described from the Red Sea along the Saudi Arabian coast. Specimens and/or photographs of this species are available from the Egyptian Red Sea to Eritrea. These specimens, formerly identified as T. taylori, differ from all other samples from the Indo-Pacific currently identified as T. taylori in having 9 and 89 dorsal- and anal-fin rays respectively (vs. usually 10 and 10 rays), 13 pectoral-fin rays (vs. usually 14 rays), and cycloid scales covering the entire predorsal region from the upper base of the pectoral fin anterior to a convex line posterodorsally to just lateral to the base of the sixth first dorsal-fin spine (vs. predorsal region mostly or entirely covered with ctenoid scales). In addition, specimens from the Red Sea form a monophyletic lineage in a Maximum Likelihood analysis of the COI gene. In this tree, the new species is the sister group to a clade composed of three lineages. One is composed of specimens from the Maldives, which is the sister group of a single available specimen from the Seychelles. These two together are the sister group of specimens of a widespread western Pacific clade.

Development and Seasonal Variations of the Larvae of Three Mesopelagic Fishes near Coral Reefs in the Red Sea

This work aims to describe the larval stages and the seasonal variation in the abundance of three mesopelagic species whose larvae are surprisingly abundant near coral reef areas in the Red Sea. The larvae were collected monthly using a plankton net (500 µ) from three coastal coral reef areas surrounding Sharm El-Sheikh on the Egyptian Red Sea coast between January and December 2015. The identification of larvae was based on the morphological and meristic characteristics according to the available literature. The larvae of this species were divided into preflexion, flexion, and postflexion stages and they were also categorized according to their size into relevant size classes. Mesopelagic fishes were represented in the collection by four species belonging to four families: Vinciguerria mabahiss (Family: Phosichthyidae), Benthosema pterotum (Family: Myctophidae), Astronesthes martensii (Family: Stomiidae; subfamily: Astronesthinae), and Trichiurus sp. (Family: Trichiuridae). In general, a total of 3678 larvae were collected, of which 1191, constituting about 32% of the total fish larvae, belonged to mesopelagic species. The most abundant species was V. mabahiss, with 677 larvae that constituted 18% and 57% of the total larvae and mesopelagic fish larvae, respectively. The second most abundant species was B. pterotum, which was represented by 485 larvae (13% of the total larvae and 40% of the mesopelagic fish larvae). A. martensii was represented by the lowest number of larvae (29 larvae, 2%). Most larvae of the three species were small and in the preflexion stage, whereas larger larvae are absent. They are highly abundant in the cooler months of the year between November and April. The high number of preflexion larvae may indicate that the three mesopelagic species spawn in the colder times of the year.

Geometry and kinematics of the Middle to Late Miocene salt tectonics, central Egyptian Red Sea margin

The Red Sea basin includes a thick Middle to Late Miocene evaporitic succession that underwent halokinesis and caused intensive reshaping of the seafloor and the development of salt-tectonic structures. However, the geometry and kinematics of these structures are still poorly understood. This study uses 2D and 3D seismic surveys and well data of the northern Egyptian Red Sea to systematically describe the distribution and morphology of salt structures, discuss their initiation, and construct a kinematic model for their origin. Our results indicate that the massive salt layer developed into five major NW-SE to NNE-SSW trending salt walls, characterized by relatively irregular crests and moderately dipping flanks. In addition, several symmetrical and asymmetrical folds and two categories of normal faults (subsalt and suprasalt) have been recognized. Based on our observations, salt mobilization in the study area started in the Late Miocene, during the precipitation of layered evaporites, and continued until the present day. In the northern Egyptian Red Sea, seismic interpretation indicates that halokinesis was triggered by a combination of thin- and thick-skinned systems, where the latter played a major role. The salt layer was welded during the Quaternary as several sags and grabens developed above the salt diapirs. Thick-skinned physical models are compatible with our observations, supporting the impact of basement faulting on Red Sea diapirism.

Monitoring temporal changes in coastal mangroves to understand the impacts of climate change: Red Sea, Egypt

This paper focuses on the current state of mangroves in Egypt, analyses how climate change is affecting mangrove forests and suggests a conservation strategy to safeguard this valuable maritime resource. Mangroves in Egypt are primarily found in regions around the Red Sea, making them popular for ecotourism across the globe. A crucial breeding and feeding ground for many commercial fishery species, mangroves are a maritime habitat that is both economically and environmentally significant and a variety of living things call them home. Mangroves are one of the most threatened tropical and subtropical ecoregions in the world. These threats come from both natural and human sources, including oil spills, human waste runoff, herbicide use, and coastal development, all of which have the potential to harm the environment. Mangrove habitats are immediately impacted by salinity changes and rising sea levels brought on by climate change. This is unfortunate as mangroves are one of the most important global carbon sinks, and their loss due to climate change may accelerate sea level rise and ocean acidification, which will cause the extinction of numerous commercial fish species. A conservation strategy should be implemented to safeguard the mangroves around the Egyptian Red Sea by using mitigation techniques, creating marine protected zones near the mangroves, and consulting the owners of the mangrove stalks. Analysis of multi-temporal satellite imagery is one of the most significant methods to assist decision-makers and environmental planners in obtaining high-precision information about environmental and climatic changes. Analysis of satellite imagery is a valuable way to detect, monitor, assess and map the environmental, human, and natural activities that are threatening the growth of the mangrove forest ecosystem. Change detection analyses using satellite imagery were conducted to evaluate the effects of rapid coastal sustainable development, including human urban and tourism activities; the decline and destruction of large areas of the mangrove forest for animal feeding along camel trade roads; and the threat of natural impacts such as flash flooding, coastal and soil erosion or human impacts such as established desalination plants and other human activities along the coastal zone of the Egyptian Red Sea.

Identification of potential antiviral compounds from Egyptian Red Sea soft corals against Middle East respiratory syndrome coronavirus

The ongoing threat of Middle East respiratory syndrome coronavirus (MERS-CoV) underscores the importance of developing effective antiviral treatments. Current research was conducted to identify potential antiviral compounds from soft corals: Sinularia leptoclados, Sarcophyton ehrenbergi, Nephthea sp., Sarcophyton glaucum and Sarcophyton regulare. The antiviral activities of soft corals extracts were evaluated against MERS-CoV. Gas chromatography-mass spectrometry (GC-MS) was used to identify bioactive compounds. The molecular docking was performed to examine the identified compounds for their binding potentials towards three pathogenic factors of MERS-CoV: main protease, spike and non-structural protein 16/10 complex. The methanolic extract of soft coral Sarcophyton regulare exhibited the most promising activity with 50% inhibitory concentration (IC50) of 4.29 µg/ml and selective index (SI) of 112.2. Among the identified compounds in the active fraction, the molecular docking showed that two fatty acid esters: hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester and octadecanoic acid, 2-hydroxy-1 (hydroxymethyl) ethyl ester had promising docking scores.

Metagenomic and metatranscriptomic exploration of the Egyptian Red Sea sponge Theonella sp. associated microbial community.

Marine sponges associated microorganisms are considered to be prolific source of bioactive natural products. Omics-based techniques such as metagenomics and metatranscriptomics have been used as effective tools to discover natural products. In this study, we used integrated metagenomic and metatranscriptomic analysis of three samples of the Egyptian Red Sea sponge Theonella sp. microbiome to obtain a complete picture of its biosynthetic activity to produce bioactive compounds. Our data revealed high biodiversity of the Egyptian sponge microbiota represented by 38 bacterial phyla with Candidate Phylum Poribacteria as the most abundant phyla with an average of 27.5% of the microbial community. The analysis also revealed high biosynthetic activity of the sponge microbiome through detecting different types of biosynthetic gene clusters (BGCs) with predicted antibacterial, cytotoxic and inhibitory bioactivity and the majority of these clusters were found to be actively transcribed. The complete BGCs of the cytotoxic theonellamide and misakinolide were detected and found to be actively transcribed. The majority of the detected BGCs were predicted to be novel as they did not show any similarity with any known cluster in the MIBiG database.

Nutritional, bioactive compounds content, and antioxidant activity of brown seaweeds from the Red Sea.

Brown seaweeds are excellent sources of bioactive molecules with a wide range of pharmacological effects, whose content can vary depending on several factors, including the origin and the environment in which the algae grow. This study aimed to estimate 19 compounds regarding primary and secondary metabolites of eight brown macroalgal species from a clean Egyptian Red Sea coast. A proximate analysis, pigment, phenolic compounds, and vitamin contents were determined. In addition, the energy content and antioxidant activity were estimated to explore the potential application of algae as functional foods to encourage the species' commercialization. Based on the chemical composition, Polycladia myrica was the most valuable species, with a comparatively high protein content of 22.54%, lipid content of 5.21%, fucoxanthin content of 3.12 μg/g, β-carotene content of 0.55 mg/100 g, and carbohydrate content of 45.2%. This species also acts as a great source of vitamin C, flavonoids, tannins, phenol content and total antioxidant capacity. The antioxidant activity of the selected algae indicated that its phenol, vitamin and pigment contents were powerful antioxidant compounds based on the structure-activity relationships. This result was verified by the strong correlation in statistical analysis at the 95% confidence level. From a worldwide perspective and based on the obtained results, these brown species may be reinforced as an essential line in future foods.

GEOGRAPHIC DISTRIBUTION AND ENVIRONMENTAL SETTING OF CLAVULINA PSEUDOPARISENSIS ANAN AROUND THE ARABIAN PENINSULA

The recent agglutinated small benthic foraminiferal species Clavulina pseudoparisensis Anan are common in the five coastal areas around the Arabian Peninsula: the Egyptian Red Sea coast between Qusseir-Marsa Alam, the Saudi Arabian Red Sea coast in Jeddah, the north Socotra Island of Yemen, the Abu Dhabi coast of the United Arab Emirates (UAE), and the east coast of Qatar of the Arabian Gulf. The taxonomy is presented and discussed. The warmer environment of the Red Sea, and also the other studied areas, favor precipitation of organic binding material for the sand grains of the arenaceous tests, which favor the forms thriving in shallow and warm environment. The recorded C. pseudoparisensis in wide geographic distribution in the Red Sea, Arabian Sea, and Arabian Gulf around the Arabian Peninsula indicates an open marine environment between these localities.