Papers by Nayrah Shaltout
4th The international conference on renewable energy research and applications (ICRERA 2015)
2015 International Conference on Renewable Energy Research and Applications (ICRERA), 2015
Sensitivity of the grooved carpet shell clam, Ruditapes decussatus (Linnaeus, 1758), to ocean acidification
Arabian Journal of Geosciences
Potential of Marine Biota and Bio-waste Materials as Feedstock for Biofuel Production
CRC Press eBooks, Aug 30, 2022
Frontiers in Marine Science
Ocean acidification (OA) is a serious consequence of climate change with complex organism-to-ecos... more Ocean acidification (OA) is a serious consequence of climate change with complex organism-to-ecosystem effects that have been observed through field observations but are mainly derived from experimental studies. Although OA trends and the resulting biological impacts are likely exacerbated in the semi-enclosed and highly populated Mediterranean Sea, some fundamental knowledge gaps still exist. These gaps are at tributed to both the uneven capacity for OA research that exists between Mediterranean countries, as well as to the subtle and long-term biological, physical and chemical interactions that define OA impacts. In this paper, we systematically analyzed the different aspects of OA research in the Mediterranean region based on two sources: the United Nation’s International Atomic Energy Agency’s (IAEA) Ocean Acidification International Coordination Center (OA-ICC) database, and an extensive survey. Our analysis shows that 1) there is an uneven geographic capacity in OA research, a...
3 Abstract: Persistent organic pollutants (POPs) continue to receive widespread attention as harm... more 3 Abstract: Persistent organic pollutants (POPs) continue to receive widespread attention as harmful contaminants in the global environment. Thirteen samples of marine surface sediment were collected from El-Mex Bay and its neighbourhood during October 2010 to determine the prevailing concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) and their impact on Mediterranean Seawaters. These compounds demonstrated markedly different distribution patterns, reflecting different domestic, agricultural and industrial usage in the area. DDTs were the major pollutant, that exhibited values <0.60-228.60 ng/g, representing 95.8% of OCPs, but their individual metabolites showed different contributions. Ratios of DDT/(DDE + DDD) in sediments indicate recent inputs of DDT into El-Mex marine environment. PCBs exhibited values <1.0-216.6 ng/g, showing high concentrations at sample locations closer to industrial areas with intensive shipping activities. Sedimen...
International Journal of Approximate Reasoning, 2021
The green algae Ulva faciata was subjected to different physical pretreatments comprising thermal... more The green algae Ulva faciata was subjected to different physical pretreatments comprising thermal and mechanical techniques at different experimental conditions to state the most appropriate method of cell disruption for increasing the quantity of the extracted lipid and hence improve the quality of the produced biodiesel with low cost. Thermal pretreatment was autoclaving of either wet or dry algal biomass, while mechanical pretreatments include microwave and ultrasonication at different time intervals. The control was the alga without pretreatment extracted at optimum conditions: 60 min, 55oC, shaking speed at 250 rpm, < 0.16 mm particle size with 25:1 v/w solvent to solid ratio. The results showed that the quantity of extracted lipids in case of using all physical pretreatments increased the Total fatty acids yield significantly by about 2-folds of the control for wet algae in hydrothermal treatment with optimum time of treatment 40 minutes, and 1.4 folds for dry algae in ther...
Inorganic carbon cycle in Alexandria Coastal water
The book illustrates the water quality of El-Mex Bay, Alexandria, Egyptian Mediterranean Coast. T... more The book illustrates the water quality of El-Mex Bay, Alexandria, Egyptian Mediterranean Coast. The book also investigate the Carbon Biogeochemical Cycle in this highly active area. The air sea carbon dioxide flux and the total emission of carbon dioxide were calculated. Also the role of biological pump and changes in pK with different salinity gradients of the Bay were also investigated. The effect of different land based sources on carbon budget and organic carbon distribution also discussed
Spatiotemporal distribution of some dissolved salts and minerals in Lake Edku connected to Mediterranean Sea: in relation to different pollutant inputs
Environmental Monitoring and Assessment, 2021
Regarding the generally accepted view of the minerals formed in solving the problem of ecosystem ... more Regarding the generally accepted view of the minerals formed in solving the problem of ecosystem pollution, this research aims to track the role of seasonal minerals in overcoming widespread pollution problems in Lake Edku. At eleven locations inside Lake Edku and three locations in the outside the water inlets, some physical and chemical parameters that affect the formation of minerals and salts were detected seasonally. As a result of human activities from 1972 to 2020, the applied remote sensing technology showed a decrease in the area of Edku Lake by 13.3%. The saturation index (SI) of twelve minerals formed in fifty-six seasonal water samples collected from fourteen locations inside and outside the lake was estimated. The saturation index (SI) of anhydrite (ANH), gypsum (GYP), calcium phosphate (CP), magnesium phosphate (MP), calcite (CAL), aragonite (ARG), dolomite (DOL), magnesite (MGS), fluorapatite (FAP), hydroxyapatite (HAP), octacalcium phosphate (OCP), and carbonate-fluorapatite (CFAP) was calculated. The presented SI values of apatite and phosphate minerals including FAP (SI 30.63–65.65), CFAP (SI 28.14–40.02), HAP (SI 24.83–31.81), Ca3(PO4)2 (SI 23.99–25.95), OCP (SI 19.96–25.47), and Mg3(PO4)2 (SI 15.80–17.46) were high. Palmer-Roger’s diagram and piper ternary diagram models reflected the abundance of NaCl in lake water with 30, 40, 46, and 75% in winter, spring, summer, and autumn, respectively. Using correlation matrix, multiple stepwise regression and cluster analysis for statistical analysis, the relationship between sedimentary minerals and outflow and drainage, as well as the role of sedimentary minerals in reducing pollution in the lake area, was outlined.
A comparative study of biosynthesized marine natural-product nanoparticles as antifouling biocides
Oceanologia, 2021
Abstract In this study, biosynthesized nanoparticles using chitosan, Ulva fasciata, and Avicennia... more Abstract In this study, biosynthesized nanoparticles using chitosan, Ulva fasciata, and Avicennia marina leaves extracts (A, B, and C, respectively), were evaluated as paint additives to control marine fouling on different substrates. These biocidal nanoparticle compounds were prepared using a green biosynthesis method. Their characterizations were conducted using Fourier-Transform Infrared spectroscopy and Transmission electron microscopy. Each nanoparticle compound was mixed with a prepared paint, resulting in three formulations for each (e.g. 1C, 2C, 3C), containing 20%, 40%, and 60% by weight. Painted PVC, wood, and steel with these nine paints, and the control were immersed in seawater for different periods. After two months of immersion, the least number of fouling species, (one species) was recorded on both the wood and steel panels that were coated with paint (1C). Meanwhile, after four months, the least numbers of fouling (four and six species) were recorded on wood and steel panels that were coated with paint (3C). After around seven months of immersion, the least numbers of fouling species (five and ten) were recorded on wood and steel panels that were coated with paints (1C and 3C), respectively. The steel panel coated with (3C), harbored ∼2% of the total number of barnacles found on the control, after 7 months of immersion. The superior antifouling agent efficiency of extract (C) nanoparticles can be attributed to its constituents of polyphenols, ammonium compounds, and high concentrations of alcohols, besides the presence of both aromatic and aliphatic amide and amide derivatives.
Egyptian Journal of Aquatic Biology and Fisheries, 2020
Chemical pretreatment of Ulva fasciata cell wall for enhancing biodiesel yield __________________... more Chemical pretreatment of Ulva fasciata cell wall for enhancing biodiesel yield _________________________________________________________________________________________
Egyptian Journal of Aquatic Biology and Fisheries, 2020
Microalgae are recognized as a promising source for biofuel production, which is known as a renew... more Microalgae are recognized as a promising source for biofuel production, which is known as a renewable source of energy. This study was conducted to optimize the biodiesel production quantitatively and qualitatively by the microalga, Nannochloropsis oculata upon culturing on two different culture media (F/2 and Boussiba media) as a comparative study through stress in the main culture compositions by 1) Treating with different salinity concentrations (20, 40 and 60psu), 2) Depleting from phosphorus (P) and nitrogen (N) sources for the two media. After different treatments, the growth rate, protein, carbohydrate, lipid, and fatty acids contents were determined. The algal analysis cleared that increasing salinity to 60psu in F/2 medium and 40psu on the Boussiba medium led to increasing the number of N. oculata cells with the maximum protein and carbohydrate contents at late exponential phase. At lower salinity, there were no significant differences in total protein content while carbohydrate contents showed slight variations, and its minimum values were obtained at (N) starved medium. Total lipid and total fatty acids content were higher in N. oculata cultured on F/2 medium than on Boussiba medium at different treatments and achieved its maximum when cultured on N-starved > P-depleted > Salt-stressed 60psu, respectively. The highest physical properties of the produced biodiesel represented in the degree of unsaturation (SD), iodine values (IV), Cetane number (CN), and oxidation stability were recorded in N. oculata cultured on higher salinities and Ndepleted conditions in the two media. Using higher salinities up to 40psu (available in the natural seawater), N-depletion or P-depletion in F/2 medium for achieving highly economical results in the production of N. oculata microalga. Biodiesel produced from N. oculata oil can be considered as a potential candidate for commercial sources.
Egyptian Journal of Aquatic Biology and Fisheries, 2019
Egyptian Journal of Aquatic Biology and Fisheries, 2019
In this investigation, optimization experiments were carried on lipid extraction and biodiesel pr... more In this investigation, optimization experiments were carried on lipid extraction and biodiesel production parameters from Ulva fasciata as a potential feed stock. This study was carried by running one to one optimization model. The results showed that, the highest yield and the best quality of biodiesel was achieved at the optimum condition of <0.16 mm algal particle size, 55 o C extraction temperature, 25:1 v/w solvent to solid ratio, 60 min extraction time and 250 rpm shaking speed, using chloroform: methanol: H 2 O (2: 2: 1) solvent mixture. The recorded lipid yield was 28.84 mg g-1 with total fatty acids ΣTFAs content 1148.94 µg g-1 , saturated fatty acids ΣSFAs=979.43 µg g-1 , monounsaturated ΣMUFAs=136.98 µg g-1 and polyunsaturated ΣPUFAs fatty acids =32.53 µg g-1. The quality of the produced biodiesel at these optimum conditions was determined by its physicochemical properties which showed a very high quality. Cetane number (CN) was 73.21, while kinematic viscosity (υ), density (ρ), higher heating value (HHV) and iodine value (IV) were 4.68 mm 2 s-1 , 0.87 g cm-3 , 39.85 MJ kg-1 and 18.48 gI 2 100g-1 fat, respectively. Other properties such as degree of unsaturation (DU), saponification value (SV) and long chain saturation factor (LCSF) recorded 17.58, 200.66mg KOHg-1 and 23.06, respectively. On the other hand, Linolenic acid (C18:3) % and Polyunsaturated fatty acid methyl esters containing ≥ 4 double bonds % recorded 0.68% and 0.98%, respectively. The initial extraction rate (h) was 6.169 ml g-1 min-1 ; the extraction capacity (Cs) was 31.036 g ml-1 ; the second order extraction constant (k) was 0.0064 ml g-1 min-1 and the coefficient of determination (R 2
American Journal of Environmental Sciences, 2015
A qualitative and quantitative study on the epiphytic microalgae and epiphytic zooplankton were c... more A qualitative and quantitative study on the epiphytic microalgae and epiphytic zooplankton were conducted in order to follow up their community structures on seaweeds in relation to some physicochemical variables in the coastal waters of the Eastern Harbor of Alexandria. Water and macroalgal samples were collected seasonally during two years successively: Winter, summer, autumn (2012) and spring (2013). The collected seaweeds were Ulva fasciata (green alga), Corallina mediterranea, Corallina officinalis, Gelidium sp., Pterocladiella capillacea, Hypnea musciformis and Grateloupia doryphora (red algae). The studied water quality parameters were pH, salinity, dissolved oxygen, oxidizable organic matter and nutrient salts. The abundance of epiphytes were significantly different between morphotypes (two-way ANOVA), p≤0.05; ranking the branched thalli as the first preference for microalgal epihytes, sheet-like thalli with a smooth surface as the second one, while the lowest rank was for the mucilaginous species. The same result was found for epiphytic zooplankton. The results of the statistics revealed insignificant seasonal variations in the epiphytic microalgae and very weak correlations between the abundance of microalgae and the physico-chemical parameters. In contrast, there were significant differences for epiphytic zooplanktonic seasonal variations. Whereas, the zooplankton count was correlated preferably with environmental water salinity, followed by nutrients.
American Journal of Environmental Sciences, 2015
In this study, fatty acids profile was determined in four algal species; namely Ulva fasciata (Ch... more In this study, fatty acids profile was determined in four algal species; namely Ulva fasciata (Chlorophyta), Corallina mediterranea, Corallina officinalis and Pterocladiella capillacea (Rhodophyta) which were collected from two sites (Abu-Qir Bay and Eastern Harbor) located on the Egyptian Mediterranean Sea during the four seasons in the period (2011-2012). In addition, nutrient content in the algal species (total nitrogen and phosphorus) and the environmental conditions of the ambient sea water were measured to find out their effect on the algal fatty acids content. The nitrogen content in algal species was almost equal in both sites. In contrast, the phosphorus content was higher in Abu-Qir (0.33-1.71%) than in Eastern Harbor (0.21-0.74%). The fatty acids profile showed different correlations with water's physico-chemical properties. The fatty acids profile of the four algal species revealed high content of SFAs against MUFA and PUFA in both sites. Consequently, the algae were screened to define the suitable site, season and species for the highest quality and quantity of biodiesel production. Biodiesel physical properties; the Degree of Unsaturation (DU), Long Chain Saturation Factor (LCSF), Cold Filter Plugging Point (CFPP), Iodine Value (IV), Saponification Value (SV), the Cetane Number (CN), Kinematic viscosity (υ), density (ρ), the Higher Heating Value (HHV), C18:3% (wt%) and double bond Db ≥4(wt%) were calculated. All the investigated algae showed biodiesel properties that follow the standard values set for optimum biodiesel, with the green alga U. faciata collected from Abu-Qir during winter, as the best choice for producing biodiesel; whereas, the extracted fatty acids from Corallina officinalis is more suitable to be used for production of blenders, which can be added to the petroleum diesel in order to increase its quality, oxidative stability and octane number.
Life Science Journal
The direct effect of an elevated CO 2 concentration range (280, 385, 550, 750 and 1050 µatm) on t... more The direct effect of an elevated CO 2 concentration range (280, 385, 550, 750 and 1050 µatm) on the marine bacterial counts and dominancy of species were examined. Our results demonstrated that the variation in glucose consumption corresponding to the incubation period (h) of bacterial community structure showed that glucose degradation as a carbon source for bacteria is in good consistency with the total bacterial count pattern. Glucose uptake and oxygen consumption are increased by increasing the temperature from 28 to 35C and also by increasing pCO 2 from nowadays pCO 2 (385µatm) to (1050 µatm). The highest consumption of glucose and oxygen was recorded in consistence with the dominancy of glucose degrading bacteria. The dominant bacterial species isolated from the Eastern Harbor, Alexandria, Egypt were counted and genetically identified. The total bacterial count (CFU/ml) increased linearly with increasing different pCO 2 at 35°C from 280 and 1050, respectively. Total bacterial count (CFU/ml) at different pCO 2 increased linearly with the incubation temperature (28-35°C). There were seven bacterial isolates from the Eastern Harbor with codes (HW1-HW7). They were affiliated according to their 16S rDNA to Bacillus cereus HW1, Psychrobacter maritimus HW2, Shima marina HW3, Pseudoalteromonas atlantica HW4, Bacillus horikoshii HW5, Oceanicola marinus HW6 and Oceanicola nanhaiensis HW7, respectively. Oceanicola nanhaiensis HW7 exhibited fluctuation in hydrolytic activities against several carbon sources. The highest activity was for lipase followed by agarase, while the lowest activity was for cellulase. This It is also concluded that ocean acidification will impact bacterial organic matter degradation by changing reaction velocities of extracellular enzymes.
The Egyptian Journal of Aquatic Research, 2014
The impacts of different CO 2 concentrations on the growth, physiology and ultrastructure of nonc... more The impacts of different CO 2 concentrations on the growth, physiology and ultrastructure of noncalcifying microalga Chaetoceros gracilis F.Schu¨tt (Diatom) were studied. We incubated Ch. gracilis under different CO 2 concentrations, preindustrial and current ambient atmospheric concentrations (285 and 385 latm, respectively) or predicted year-2100 CO 2 levels (550, 750 and 1050 latm) in continuous culture conditions. The growth of Ch. gracilis measured as cell number was decreased by increasing the pCO 2 concentration from nowadays concentration (385 latm) to 1050 latm. The lowest percentage changes of oxidizable organic matter, nitrite, nitrate, phosphate and silicate were recorded at a higher pCO 2 (1050 latm), and this is in consistence with the lowest recorded cell number indicating unsuitable conditions for the growth of Ch. gracilis. The minimum cell numbers obtained at higher levels of CO 2 clearly demonstrate that, low improvement occurred when the carbon level was raised. This was confirmed by a highly negative correlation between cell number and carbon dioxide partial pressure (r = À0.742, p 6 0.05). On the other hand, highest growth rate at pCO 2 = 385 latm was also confirmed by the maximum uptake of nutrient salts (NO 3 = 68.96 lmol.l À1 , PO 4 = 29.75 lmol.l À1 , Si 2 O 3 = 36.99 lmol.l À1). Total protein, carbohydrate and lipid composition showed significant differences (p 6 0.05) at different carbon dioxide concentrations during the exponential growth phase (day 8). Transmission Electron Microscopy of Ch. gracilis showed enlargement of the cell, chloroplast damage, disorganization and disintegration of thylakoid membranes; cell lysis occurs at a higher CO 2 concentration (1050 latm). It is concluded from this regression equation and from the results that the growth of Ch. gracilis is expected to decrease by increasing pCO 2 and increasing ocean acidification.
The Egyptian Journal of Aquatic Research, 2015
The seasonal fluoride distribution in surface waters along Lake Edku and in the supplying land dr... more The seasonal fluoride distribution in surface waters along Lake Edku and in the supplying land drains, as well as its effect on the formation of carbonated and fluoridated minerals were investigated. The data revealed that fluoride's content was affected by the chlorinity value of two feeding sources of water in Lake Edku, which were the seawater from El-Maadiya inlet and drainage water from land drains. Fluoride in surface water showed average contents of 0.62-1.59, 0.44-1.53, 0.13-1.07 and 0.23-1.17 mg/l in winter, spring, summer and autumn, respectively, with an annual average concentration of 0.8 ± 0.1 mg/l. The annual average of the saturation index (SI) of carbonated (calcite, aragonite and dolomite) and fluorapatite minerals along Lake Edku had values that exceeded the unity and referred to the over saturation of the lake water in respect to these minerals. In contrast, the average annual SI of fluorite and sellaı¨te gave values lower than unity. That indicated the under saturation in respect to these two minerals. The high saturation index values for fluorapatite may be related to the low solubility of calcite in apatite supernatants in alkaline conditions. Interestingly, the formation of the fluorapatite mineral leaves a small concentration of it, and that protects Lake Edku's ecosystem from the destructive impact of fluoride pollution.
Physico-Chemical Characteristics of Different Water Types in El-Mex Bay, Alexandria, Egypt
Proceedings of OCEANS 2005 MTS/IEEE
ABSTRACT
Desalination and Water Treatment, 2014
Uploads
Papers by Nayrah Shaltout