Red Sea Coastal Area Research Articles

Assessment of CMIP6 models’ performances and projection of precipitation based on SSP scenarios over the MENAP region

Abstract Precipitation is the main component of the hydrological cycle. It has a significant effect on the ecosystem especially, irrigation and drainage system design and management, crop production, and flood and drought management. In this study, 11 global circulation models (GCMs) from Coupled Model Intercomparison Project phase 6 (CMIP6) were investigated under three shared socioeconomic pathway (SSP) scenarios for precipitation simulation and projection in the future period (2021–2050). Then, the results were compared with the base period (1985–2014). The research was conducted in the MENAP region. The evaluation of GCMs’ performances by the Taylor diagram, R2, MSE, MAE, and RMSE indices showed that among the 11 models, the MPI-ESM1-2-HR model with an average R2 and RMSE of 0.6 and 18.9, respectively, was more accurate than other models in precipitation simulation in the entire region. The projection of precipitation indicated that the precipitation will mainly decrease except in areas such as the Black Sea, Mediterranean, and Red Sea coastal areas as well as mountainous and higher altitude regions in the eastern part of the study area. In addition, highest decrease rates will happen in the Middle East countries, Afghanistan, Morocco, Algeria, and Sudan. Based on different scenarios in the MENAP region, precipitation will vary between −77.3 and + 51.1 mm compared to the base period. Moreover, the lowest and highest precipitation changes were estimated based on SSP1-2.6 and SSP5-8.5 scenarios. According to the various scenarios, the amount of precipitation in the future period will decrease compared to the historical period in most parts of the areas under study.

Bubble mobility in seawater during free-rise, bouncing, and coalescence with the seawater-air interface

The way bubbles in seawater interact with the seawater-air interfaces plays an important role in many naturally occurring processes. Here we use high-speed video imaging to investigate how millimeter-sized bubbles free-rise, bounce, and coalesce with the seawater-air interface in seawater samples collected from the Red Sea coastal area. The samples salinity and organics content are typical for the open oceans and seas. To evaluate the seawater-air interface mobility, which is one of the fundamental properties determining the bubble hydrodynamic interactions, we measure the free-rise velocity of the bubbles and their bouncing trajectories from the interface. Our experiments demonstrate that both the bubble interface and the pool seawater-air interface are fully mobile, indicating that the presence of high concentration of electrolytes and organics in the seawater does not affect the interfaces mobility during free-rise and bouncing for these bubble sizes. In contrast, the presence of electrolytes in the seawater is shown to increase the characteristic time for the final bubble coalescence with the interface from milliseconds to seconds. Whereas the delay of the bubble coalescence by the high concentration of the electrolyte is a well-known phenomenon, here we evaluate this effect for single bubbles in actual seawater samples to separate the effects of the electrolyte and organic components.

Evaluation of halophilic microalgae isolated from Rabigh Red Sea coastal area for biodiesel production: Screening and biochemical studies

In the present study, different water samples from Red Sea coastal area at Rabigh city, Saudi Arabia were studied for their dominant algal species. Microalgal isolation was carried out based on dilution method and morphologically examined using F/2 as a growth medium. Dry weight and main biochemical composition (protein, carbohydrates, lipids) of all species were performed at the end of the growth, and biodiesel characteristics were estimated. Nannochloropsis sp., Dunaliella sp., Tetraselmis sp., Prorocentrum sp., Chlorella sp., Nitzschia sp., Coscinodiscus sp., and Navicula sp. were the most dominant species in the collected water samples and were used for further evaluation. Nannochloropsis sp. surpassed all other isolates in concern of biomass production with the maximum recorded dry weight of 0.89 g L−1, followed by Dunaliella sp. (0.69 g L−1). The highest crude protein content was observed in Nitzschia sp. (38.21%) and Dunaliella sp. (18.01%), while Nannochloropsis sp. showed 13.38%, with the lowest recorded lipid content in Coscinodiscus sp. (10.09%). Based on the growth, lipid content, and biodiesel characteristics, the present study suggested Dunaliella sp. and Nitzschia sp. as promising candidates for further large-scale biodiesel production.

Zooplankton and meiobenthos diversity at the intertidal sandy shores of Jizan and Farasan coastal areas of Red Sea.

Distinctive studies were conducted for the identification of meiobenthos and zooplankton at Farasan Islands and Jizan sandy shores. The present work compares the meiobenthos and zooplankton communities at Alhsas sandy shore at Farasan Islands and As-Suways sandy shore at Jizan. Population density, species richness and Shannon-Weiner diversity index were determined for meiobenthos and zooplankton inhabiting both the studied sites. Water criteria; surface water temperature, pH and conductivity were determined for each investigated site. Eleven zooplankton species were defined at Alhsas sandy shore Farasan, nine species were identified at the littoral zone at As-Suways sandy shore, Jizan. Ten meiobenthos species were defined at Alhsas site, Farasan. Only eight meiobenthos species were defined at the intertidal zone of As-Suways site, Jizan. The results were discussed to highlight the effect of water criteria on the spatial distribution of zooplankton and meiobenthos at the investigated sites.

중세와 르네상스 지도의 오빌의 지리적 위치와 그 변화에 대한 연구

The purpose of this study is to investigate the geographic location of Ophir and its change on maps made during the Middle Ages and Renaissance. For this, maps produced in each period were investigated, and the maps were classified and analyzed by period and site. As a result of the analysis, it was confirmed that in the Middle Ages, the coastal area on the west side of the Indus River, the Ganges River basin, the Red Sea coastal area, and islands on the Red Sea were marked. It was also confirmed that during the Renaissance, the site moved to Hispaniola, Peru, the Spice Islands, and Sofala. In addition, Tarshish was marked in the west of Cathay in the Middle Ages, but in the Renaissance, it was confirmed that it was located in a place close to Ophir. Theological interpretations of Native Americans and knowledge gathered from locals by explorers also influenced Ophir’s positional markings. After 1600 Ophir disappeared from maps other than Bible maps.

Red Sea MODIS Estimates of Chlorophyll a and Phytoplankton Biomass Risks to Saudi Arabian Coastal Desalination Plants

Harmful algal blooms (HABs) and the high biomass associated with them have afflicted marine desalination plants along coastal regions around the world. Few studies of HABs have been conducted in the Red Sea, where desalination plants along the Saudi Arabian Red Sea coast provide drinking water for millions of people. This study was conducted along the Saudi Arabian Red Sea coast from 2014 to 2015 to assess the potential for using Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing of chlorophyll a (Chl a) or fluorescence line height (FLH) to identify risks for biofouling at these desalination plants. Ship-based surveys of phytoplankton were conducted along the Saudi Arabian coastline offshore of desalination plants at Jeddah, Al Shoaibah and Al Qunfudhuh to assess the density of phytoplankton populations and identify any potential HAB species. Ship-based surveys showed low to moderate concentrations of phytoplankton, averaging from 1800–10,000 cells L−1 at Jeddah, 2000–11,000 cells L−1 at Al Shoaibah and 1000–20,500 cells L−1 at Al Qunfudhuh. Sixteen different species of potentially toxigenic HABs were identified through these surveys. There was a good relationship between ship-based total phytoplankton counts and monthly averaged coastal MODIS Chl a (R2 = 0.49, root mean square error (RMSE) = 0.27 mg m−3) or FLH (R2 = 0.47, RMSE = 0.04 mW m−2 µm−1 sr−1) values. Monthly average near shore Chl a concentrations obtained using MODIS satellite imagery were much higher in the Red Sea coastal areas at Al Qunfudhuh (maximum of about 1.3 mg m−3) than at Jeddah or Al Shoaibah (maximum of about 0.4 and 0.5 mg m−3, respectively). Chlorophyll a concentrations were generally highest from the months of December to March, producing higher risks of biofouling desalination plants than in other months. Concentrations decreased significantly, on average, from April to September. Long-term (2005–2016) monthly averaged MODIS Chl a values were used to delineate four statistically distinct zones of differing HAB biomass across the entire Red Sea. Sinusoidal functions representing monthly variability were fit to satellite Chl a values in each zone (RMSE values from 0.691 to 0.07 mg m−3, from Zone 1 to 4). December to January mean values and annual amplitudes for Chl a in these four sinusoidal functions decreased from Zones 1–4. In general, the greatest risk of HABs to desalination occurs during winter months in Zone 1 (Southern Red Sea), while HAB risks to desalination plants in winter months are low to moderate in Zone 2 (South Central Red Sea), and negligible in Zones 3 (North Central) and 4 (Northern).

Integration of remotely sensed and seismicity data for geo-natural hazard assessment along the Red Sea Coast, Egypt

The flooding and seismic activity analysis clearly shows the urgent need for an evaluation planning program to mitigate hazard for the vital areas. The Red Sea coastal area is always exposed to the risk of flash floods and earthquakes; therefore, the management and determination of geo-hazard in these areas are critically important. A risk map was produced for the study area by integrated flash flooding and seismicity data. Several valuable data have been applied to accomplish this work which include ALOS-PALSAR, satellite images, and earthquake data. Seismic hazard assessment was performed using probabilistic earthquake hazard assessment; Results of the iso-acceleration maps and hazard curves for a return period of 475 years showed that the seismic hazard values increase from southern to northern parts. The morphometric parameter interpretations illustrate that 6 sub-basins (40% of total sub-basins) are of high-flooding hazardous, 5 sub-basins of moderate hazard (33.33%), and 4 of low hazard (26.66%). Finally, geo-hazard map results markedly increase from south to north in the study area. So, we recommend that some dams and channels should be constructed in vital sites along and at the end of the channel Wadi to protect it against flood hazards along the Red Sea Coast for long-term sustainable development without problems. These findings can be a potential guide for decision-makers in disaster geo-hazard reduction in this interest coastal area.

Evaluation of sediment contamination in the Red Sea coastal area combining multiple pollution indices and multivariate statistical techniques

In the recent years, the Red Sea coast of Yemen has been severely affected by intensive anthropogenic activities. The current study constitutes a thorough inquiry to evaluate the extent of heavy metals pollution in Yemen's Red Sea coast sediment and identifies the possible sources of pollution. The concentrations of five metals (copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), and nickel (Ni)) collected from nine sites along the Red Sea coast of Yemen were assessed using an atomic absorption spectrophotometer (ASS). Sediment quality indices, such as the sediment quality guidelines (SQGs), potential ecological risk (RI), contamination factor (CF), pollution load index (PLI), geoaccumulation index (Igeo), and modified degree of contamination (mCd) were computed. In addition, multivariate statistical techniques (principal component analysis (PCA), hierarchical cluster analysis, and Pearson's correlation analysis) were applied to identify the potential sources of metals. The mean concentrations of Cu, Zn, Cd, Pb, and Ni were 51.3, 61.9, 4.02, 9.9, and 33.4 mg/kg dry wt, respectively. The spatial distribution revealed that the metals concentrations were high at the middle zone and low southward of Hodeida city. According to the SQGs, the adverse biological effects of metals were occasionally associated with Cu and Cd, frequently associated with Ni, and not expected to occur with Zn and Pb. The RI indicated that the sediment of the studied sites pose low (RI < 50) to considerable (100 ≤ RI < 200) ecological risk. The mean effect range-median quotient (M-ERM-Q) indicated that the combination of the studied metals had the toxicity probability of 21% at all studied sites. Igeo and CF indicated that the metals concentrations were in the descending order of: Zn > Ni > Pb > Cd > Cu, whereas the PLI and mCd indicated that Ras Isa (Site 5) and Urj village (Site 6) were the most polluted sites. PCA, cluster analysis, and correlation analysis found that Cd, Pb, and Ni mostly originated from anthropogenic sources while Cu and Zn were mainly derived from natural sources. Thus, it is evident that the intensive anthropogenic activities had negative influence on metals accumulation in the sediment of the Red Sea coast of Yemen leading to detrimental effects to the whole ecosystem. These comprehensive findings provide valuable information and data for future monitoring studies regarding heavy metals pollution and sediment quality at the Red Sea coast of Yemen.

Antibacterial Silver Nanomaterial Synthesis From Mesoflavibacter zeaxanthinifaciens and Targeting Biofilm Formation.

Considering the significance of biological and eco-friendly nanomaterials, in the present study, we have synthesized silver nanoparticles from the exopolysaccharide of recently recovered bacterial strain CEES51 from the Red Sea coastal area of Jeddah, Saudi Arabia. 16S ribosomal RNA gene sequencing was used to characterize the isolated bacteria, and it was identified as Mesoflavibacter zeaxanthinifaciens and assigned an accession number MH707257.1 GenBank. The bacterial strain is an excellent exopolysaccharide producer and survived at hypersaline (30%) and high-temperature (50°C) conditions. The bacterial exopolysaccharides were employed for the fabrication of silver nanoparticles at room temperature. UV-visible spectrophotometer optimized the synthesized nanoparticles, and their size was determined by Nanophox particle size analyzer and dynamic light scattering. Additionally, the X-ray powder diffraction and Fourier-transform infrared spectroscopy studies also approved its crystalline nature and the involvement of organic functional groups in their formation. The synthesized nanomaterials were tested for their antibacterial and antibiofilm properties against pathogenic microorganisms Bacillus subtilis and methicillin-resistant Staphylococcus aureus. The antimicrobial property showed time, and dose-dependent response with a maximum of zone inhibition was observed at around 22 and 18 mm at a dose of 50 µg/well against B. subtilis and S. aureus and a minimum inhibitory concentration of 8 and 10 µg/ml, respectively. Furthermore, the synthesized silver nanoparticles possessed a substantial antibiofilm property and were also found to be biocompatible as depicted by red blood cell lysis assay and their interaction with peripheral blood mononuclear cells and human embryonic kidney 293 cells. Therefore, Mesoflavibacter zeaxanthinifaciens is found to be an excellent source for exopolysaccharide synthesis that assists in the silver nanoparticle production.

Automatic determination of shoreline at maximum retreating

Coastal zones are the most influenced areas by global sea level rising. One of the important coastal zones in Egypt is the Red Sea. Red Sea coastal area is an attractive touristic area, which still under development. For the high value of such areas, the position of the set-back construction line is required for well planning and development. This position influenced greatly by the position of the shoreline at the maximum retreating. This paper introduces an automatic approach for determining the shoreline at the maximum retreating. This approach depends on three types of information; 1) the location of the current shoreline, 2) the mean higher high-water level (MHHWL), and 3) the topography of the coastal area.A study area North of Hurghada, is selected to apply the introduced approach. The shoreline is extracted out of Landsat-8 images based on a combination of three factors; a modified normal difference water index, the reflectance values of the water bodies in specific bands within the shortwave infra-red spectrum, and the relation of the reflectance values of water bodies in the Green, Red, NIR, and SWIR bands. The higher high-water level is determined from near tidal gauge station that has collected data each 30 min since 2008, and the topography of the coastal area is determined by the Kinematic GPS technique. The extracted shoreline was assessed by comparing it to actual shoreline traced on the ground. The results show that the accuracy of the extracted shoreline is within 15 m of the actual shoreline.

MODIS Derived Sea Surface Salinity, Temperature, and Chlorophyll-a Data for Potential Fish Zone Mapping: West Red Sea Coastal Areas, Saudi Arabia.

In this study, a multi-linear regression model for potential fishing zone (PFZ) mapping along the Saudi Arabian Red Sea coasts of Yanbu’ al Bahr and Jeddah was developed, using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data derived parameters, such as sea surface salinity (SSS), sea surface temperature (SST), and chlorophyll-a (Chl-a). MODIS data was also used to validate the model. The model expanded on previous models by taking seasonal variances in PFZs into account, examining the impact of the summer, winter, monsoon, and inter-monsoon season on the selected oceanographic parameters in order to gain a deeper understanding of fish aggregation patterns. MODIS images were used to effectively extract SSS, SST, and Chl-a data for PFZ mapping. MODIS data were then used to perform multiple linear regression analysis in order to generate SSS, SST, and Chl-a estimates, with the estimates validated against in-situ data obtained from field visits completed at the time of the satellite passes. The proposed model demonstrates high potential for use in the Red Sea region, with a high level of congruence found between mapped PFZ areas and fish catch data (R2 = 0.91). Based on the results of this research, it is suggested that the proposed PFZ model is used to support fisheries in determining high potential fishing zones, allowing large areas of the Red Sea to be utilized over a short period. The proposed PFZ model can contribute significantly to the understanding of seasonal fishing activity and support the efficient, effective, and responsible use of resources within the fishing industry.

Distribution and assessment of heavy metals in the coastal area of the Red Sea, Egypt.

In order to evaluate the contamination state of the Red Sea coastal area, concentrations of heavy metals (Cu, Zn, Cd, Pb, Fe and Mn) were determined in sea water and surface sediments along the western side from Suez to Shalateen. The studied locations were selected to cover potential natural and anthropogenic sources of metal input in the Egyptian Red Sea. Levels of Cu, Zn, Cd, Pb, Fe and Mn in water were 0.85 - 2.61, 2.13 - 14.42, 1.24 - 4.51, 0.11 - 0.31, 8.44 - 33.71 and 0.30 - 0.62 µg/l; while in sediments were 25.67 - 100.77, 52.60 - 143.00, 21.20 - 63.43, 1.23 - 6.63, 11632 – 28321 and 291.43 - 803.80 µg/g, respectively. There were obvious positive correlations between Cu, Zn, Pb and Fe in water; while sediments showed positive correlations between Cd, Zn and Pb as well as between Fe and Mn. The obtained data were further subjected to Principal Component Analysis (PCA). The results lend support to the argument that specific geographical distribution of heavy metals in Red Sea could be related to different types of metal input. In Suez area, highest metal load in water and sediments was due to combined effects of wastes discharge and maritime activities. High contamination of Cd, Zn and Pb in sediments was associated with the shipping process of phosphate ore, while elevated Fe and Mn levels were principally associated with natural input of terrigenous sediments. The sediments indices of enrichment factor and geo-accumulation index showed high enrichment of Pb and Cd due to contamination from phosphate shipping; and the inflow with terrigenous sediments led to moderated to highly contamination with Fe and Mn.

The impact of eustasy, tectonics, and paleoclimate on the dolomitization of the syn-rift Neogene carbonate platforms in the Red Sea coastal area, Egypt

A very significant quantity of dolomites and dolomitic limestones of variable origins occurs in the syn-rift Neogene carbonate platforms of the NW Red Sea coast and the Gulf of Suez. These are more common in the Um Diheisi Member of the Ranga Formation (early Miocene), the Um Mahara Formation (middle Miocene), the Um Gheig Formation (late Miocene), and the Dashet El Dabaa Member of the Shagra Formation (Pliocene). Based on their stratigraphic distribution, petrography, and cathodoluminescent characteristics, as supported by geochemical data, syn-rift irregular morphotectonic relief, and the eustasy, four distinct types of dolomites have been identified and were interpreted as follows: 1) Syndepositional stratiform dolomicrite of the Um Diheisi Member occurred in structurally half graben restricted basins favoring structural sites of cyclic peritidal dolomitization that developed in response to sea transgression and then short-term sea level fall of each cycle period. 2) Regional replacive dolomite of the Um Mahara Formation involved mixing meteoric, marine, and hypersaline waters associated with the highstand sea level and then the repeated emergence of the platform and the temporal drowning with restricted marine waters. 3) Mixed syndepositional, replacive, and void-filling cement dolomites of the Um Gheig Formation, which suggest three dolomitization events:- i- an early, penecontemporaneous dolomite associated with highstand phases; ii- diagenetic dolomites formed by mixing meteoric and hypersaline reflux waters during lowstands and falling sea level, and iii- the latest dolomitization phase that occurred as dolomite cement involving hydrothermal fluids during the exposure periods. 4) Replacive dolomite of the Dashet El Dabaa Member, which involved mixtures of hypersaline and marine waters. Paleoclimate played an important role in the dolomitization of the Neogene sediments. An arid climate prevailed during the dolomite of the Um Diheisi Member and the early dolomitization phases of the Um Gheig Formation. A humid climate predominated in the replacive dolomite of the Um Mahara Formation, in which the meteoric groundwater allowed the dissolution of precursor limestones and subsequent formation of extensive bodies of dolomites. Arid conditions also prevailed during the dolomitization of the Dashet El Dabaa Member, as evidenced by the lack of dissolution and the abundance of well-preserved unstable feldspars.

Textural characteristics of sediments along the southern Red Sea coastal areas, Saudi Arabia

A lack of understanding exists of the origin and textural characteristics of Saudi Arabian Red Sea coastal sediments. This paper concerns the southern coastline of Jizan on the Saudi Red Sea. It is some 160 km long characterised by either narrow rocky headlands with intermittent pocket beaches or wide low-lying beaches dissected by wadis. Granulometric testing of samples from 135 locations showed that beach sand size was mainly very fine to medium grained (Mz = 3.93 O), sorting ranged from 1.65 to 0.41 and skewness values from −051 to 0.39, being mainly negative; dune sands were medium to fine grained (Mz = 1.13 O; average sorting 2.8), while skewness variations within dune samples indicated symmetrical to fine skewed values (бΙ = 0.55 to 0.89). Most foreshore samples were derived from wadis. Wadi mud levels can be high, e.g. Baysh (84%), and wadi Samrah (90%) with mean grain size ranging from very fine to medium sand (Mz = 3.9 O), sorting being well to poor (0.45 to 1.52) due to sediment influxes. Sabkha had a wide range of sand/mud and significantly higher carbonate percentages than other environments. Sediment source differences and littoral reworking contributed to grain size variation. The carbonate content varied between 1.5 and 31.5% due to hinterland contributions, and spatial analysis showed increasing quantities of carbonate minerals towards the south. On the wider geographical front, findings from Jizan are similar to those of the Northern United Arab Emirates (UAE), including sabkhas, being composed of sand, skeletal carbonate, fine fluvial material and wind-blown silt and clay components of wadi origin. Further work on the northeastern Red Sea edge can hopefully confirm these findings.

Seasonal dynamics in the relative density of aquatic flora along some coastal areas of the Red Sea, Tabuk, Saudi Arabia

Plants are the producers of all autotrophic ecosystems’ and are the base of the food chain taking energy from the sun and converting it into food for all other organisms through photosynthesis. Plants grow in certain places and seasons when the environmental factors are suitable for their germination, growth and developments that influence their diversity. Environmental factors can include abiotic factors such as temperature, light, moisture, soil nutrients; or biotic factors like competition from other plants or grazing by animals. Anthropogenic perturbations can also influence distribution patterns. Monitoring of ecological habitats and diversity of some aquatic flora along some coastal areas of Red Sea has been done to understand the dynamics of aquatic plants influenced by prevailing environmental and anthropogenic perturbations The results of this research showed that the summer season is the most suitable period for the study of aquatic plant diversity along the coastal sites of Red Sea. The aquatic flora had high relative density and diversity in April, May, June and July and these four months of the summer season are best for collection of aquatic plants from the selected coastal areas of Red Sea for medicinal purposes and ecological studies.

Aerosol optical depth trend over the Middle East

Abstract. We use the combined Dark Target/Deep Blue aerosol optical depth (AOD) satellite product of the moderate-resolution imaging spectroradiometer (MODIS) collection 6 to study trends over the Middle East between 2000 and 2015. Our analysis corroborates a previously identified positive AOD trend over large parts of the Middle East during the period 2001 to 2012. We relate the annual AOD to precipitation, soil moisture and surface winds to identify regions where these attributes are directly related to the AOD over Saudi Arabia, Iraq and Iran. Regarding precipitation and soil moisture, a relatively small area in and surrounding Iraq turns out to be of prime importance for the AOD over these countries. Regarding surface wind speed, the African Red Sea coastal area is relevant for the Saudi Arabian AOD. Using multiple linear regression we show that AOD trends and interannual variability can be attributed to soil moisture, precipitation and surface winds, being the main factors controlling the dust cycle. Our results confirm the dust driven AOD trends and variability, supported by a decreasing MODIS-derived Ångström exponent and a decreasing AERONET-derived fine mode fraction that accompany the AOD increase over Saudi Arabia. The positive AOD trend relates to a negative soil moisture trend. As a lower soil moisture translates into enhanced dust emissions, it is not needed to assume growing anthropogenic aerosol and aerosol precursor emissions to explain the observations. Instead, our results suggest that increasing temperature and decreasing relative humidity in the last decade have promoted soil drying, leading to increased dust emissions and AOD; consequently an AOD increase is expected due to climate change.

Wind resource characterization in the Arabian Peninsula

Wind energy is expected to contribute to alleviating the rise in energy demand in the Middle East that is driven by population growth and industrial development. However, variability and intermittency in the wind resource present significant challenges to grid integration of wind energy systems. These issues are rarely addressed in the literature of wind resource assessment in the Middle East due to sparse meteorological observations with varying record lengths. In this study, the wind field with consistent space–time resolution for over three decades at three hub heights (50m,80m, 140m) over the whole Arabian Peninsula is constructed using the Modern Era Retrospective-Analysis for Research and Applications (MERRA) dataset. The wind resource is assessed at a higher spatial resolution with metrics of temporal variations in the wind than in prior studies. Previously unrecognized locations of interest with high wind abundance and low variability and intermittency have been identified in this study and confirmed by recent on-site observations. In particular, the western mountains of Saudi Arabia experience more abundant wind resource than most Red Sea coastal areas. The wind resource is more variable in coastal areas along the Arabian Gulf than their Red Sea counterparts at a similar latitude. Persistent wind is found along the coast of the Arabian Gulf.

The use of biotic and abiotic components of Red Sea coastal areas as indicators of ecosystem health.

A biomonitoring study was conducted using some biotic (Pomadasys hasta and Lutjanus russellii fish) and abiotic (water and sediment) components of the Red Sea coast of Hodeida, Yemen Republic along two polluted sites (Al-Dawar beach and Urj village) in comparison to a reference site (Al-Nukhailah beach). The studied fish biomarkers included hepatosomatic index (HSI), condition factor (K), scaled mass index (SMI), catalase, glutathione-S-transferase (GST), malondialdehyde (MDA), total protein and albumin. In addition, metals (Fe, Cu, Zn, Pb and Cd) concentrations in water and sediment were measured and sediment pollution assessment was carried out using contamination factor (CF), geoaccumulation index (Igeo), pollution load index (PLI) and enrichment factor (EF). The studied metals concentration in water and sediment samples showed significant increase among the polluted sites in comparison to the reference site. Sediment pollution assessment generally confirmed that Urj village was the most contaminated site followed by Al-Dawar beach. Catalase, GST and MDA proved to be the most responsive biomarkers with increased values of GST and MDA at sites influenced by agricultural, urban and industrial activities while catalase, HSI, K, SMI, total protein and albumin showed the opposite trend. This study recommends monitoring of sediment Igeo and EF values as well as SMI, catalase, GST and MDA as sensitive indicators of different anthropogenic activities and their effects on aquatic ecosystems under complex and different gradients of metal pollution. In addition, P. hasta proved to be more sensitive towards the detected pollution condition.

Heavy metals contamination and distribution of benthic foraminifera from the Red Sea coastal area, Jeddah, Saudi Arabia

Summary The distribution of benthic foraminifera was studied in two stations in the coastal area, located around Jeddah, Red Sea coast, Saudi Arabia. Thirty-three species belonging to 15 genera, 14 families and three suborders were recorded in twenty samples. Some foraminiferal tests display abnormalities in their coiling, general shape of chambers and apertures. On the other hand, concentrations of Fe, Mn, Zn, Cu, Pb, Ni, Cr, and Cd were measured in the tests of the two most common living species of benthic foraminifera (Sorites marginalis and Peneroplis planatus). Significant spatial differences in the metal concentrations of benthic foraminifera were recorded at the two sites. Benthic foraminifera yielded significantly high concentrations of Fe, Mn, Pb and Cu, which may attribute to anthropogenic activities at the studied coastal areas. The anthropogenic activities have a considerable impact, besides other factors, in the abnormalities of foraminiferal test.

Performance assessment of prepared polyamide thin film composite membrane for desalination of saline groundwater at Mersa Alam-Ras Banas, Red Sea Coast, Egypt

This study aims to enhance the performance of the flat sheet thin-film composite (TFC) polyamide–polysulfone reverse osmosis (RO) membranes. Composite RO membranes with high salt rejection were fabricated by treating a porous polysulfone (PS) support sequentially with a di-amine and then with a polyfunctional acid chloride, thereby forming a thin film of polyamide (PA) on the PS support. In order to establish conditions for the development of suitable thin-film composite (PS/TFC) membranes, various parametric studies were carried out which included varying the concentration of reactants, reaction time, curing temperature, and curing time for thin-film formation by the interfacial polymerization technique. By suitable combination of these factors, 2.0 wt.% MPD, 0.5 wt.% TMC, 60-s reaction time, 80°C curing temperature, and curing time 10 min., a desired thin film of PA with improved performance for groundwater desalination could be obtained. Further, a combination of scanning electron microscopy (SEM), attenuated total reflectance infrared (ATR-IR), X-ray diffraction (XRD) was utilized to confirm the existence and to examine the morphology of the PS/TFC membrane. Pilot-scale RO filtration unit was used to study the performance of the fabricated membranes for desalinating brackish, saline groundwater of Red Sea coastal area. Salt rejections percent for various feeds were found to be in the range of 90.6–98.5.