Egyptian Coastal Waters Research Articles

Microplastics Pollution in Aquatic Environment: A Review of Abundance, Distribution, and Composition in the Egyptian Coastal Waters

Microplastics Pollution in Aquatic Environment: A Review of Abundance, Distribution, and Composition in the Egyptian Coastal Waters

Toxic phenolic compounds in the Egyptian coastal waters of Alexandria:spatial distribution,source identification,and ecological risk assessment

ABSTRACT Poor published data are available for the detections of toxic phenolic compounds in the Egyptian Mediterranean Coast. Seasonal and spatial distributions of eight driven toxic phenolic compounds in coastal waters of Alexandria from ten different locations, situated between Abu Qir bay and Eastern Harbor during July, December (2018), and February, April (2019), were investigated to determine contamination status, possible sources, and ecological risks in the study area. For that purpose, a method was optimized for derivatization and detection of methylphenols, chlorophenols, and nitrophenols in water samples using GC-MS. This analytical method was validated using matrix spikes, indicating detection limits (0.02–0.5 µg/ml) and good recoveries (70–120%). Ranges of phenol concentrations in water samples were as follows: phenol (<LOD-109.2 ng/l), 2,4-DMP (<LOD-117.68 ng/l), 2-nitophenol (<LOD −87.09 ng/l), 2,4 dichlorophenol (19.93–66.30 ng/l), pentachlorophenol (13.50–60.08 ng/l), 2-chlorophenol (13.23–91.43 ng/l), 2,4,6-trichlorophenol (12.9–46.04 ng/l), and 4-chloro-3-methylphenol (15.2–52.3 ng/l). Methylphenols were the major group detected followed by nitrophenols and chlorophenols. Results of the risk assessment revealed that concentrations of the studied phenols were within the safe limits and lower than Surface Water Toxicity Reference Values (TRVs), giving no indication of pollution. Multivariate statistical analysis with different physicochemical parameters of water indicated the greatly variable behavior of phenolic compounds, and the exact sources of these compounds are difficult to identify since no major point sources of pollution are known in the area of study.

Antifungal Potential of the Bioactive Constituents in Extracts of the Mostly Untapped Brown Seaweed Hormophysa cuneiformis from The Egyptian Coastal Waters

MYCOSES and plant fungal pathogens are limiting factors highly affecting public health and crop production. Some fungal strains have been documented to be resistant to the commonly used drugs. Therefore, finding out new and pivotal antifungal drugs is becoming a global priority. Herein, we evaluated the in vitro antifungal activities of different crude polar (methanol and ethyl acetate) and non-polar (chloroform and petroleum ether) extracts of the mostly untapped brown seaweed Hormophysa cuneiformis (order Fucales, Phaeophyceae), in the Egyptian coastal waters, against eight pathogenic fungi: Aspergillus flavus, A. fumigatus, Candida albicans and Trichosporonas ahii (as human pathogens), and Alternaria alternata, Cladosporium herbarum, Fusarium oxysporum and Penicillium digitatum (as plant pathogens). The agar well diffusion assay was applied. Our findings showed that the chloroform extract only exhibited a potential antifungal activity against all tested fungal isolates, particularly T. asahii, C. albicans, A. fumigatus and C. herbarum, while the other extracts had relatively no remarkable effects. The minimum inhibitory concentrations (MICs) ranged between 0.78 and 6.25μg.ml-1 and these values are very close to those of the standard antifungal drug amphotericin B (0.63–5μg.ml-1). GC–MS analysis of the crude chloroform extract revealed 45 different bioactive compounds, mainly including 18 different species of saturated, monounsaturated and polyunsaturated fatty acids (71.48%) and some essential oils. The major constituents were arachidonic (C20:4, ω–6; 16.18%), oleic (C18:1, ω–9; 15.61%), palmitic (C16:0; 9.18%) and dihomo-γ-linolenic (C20:3, ω–6; 8.97%) fatty acids.

Biochemical composition of some Egyptian seaweeds with potent nutritive and antioxidant properties

The present study investigated the biochemical composition of three seaweeds; Ulva fasciata (Chlorophyta), Sargassum linifolium (Phaeophyta) and Corallina officinalis (Rhodophyta). Total chlorophyll content was maximum in U. fasciata (34.06mg/g dry wt.) while carotenoid content was the highest in C. officinalis (3.8 mg/g dry wt.). The uppermost level of carbohydrates was (27.98% of dry wt.) in C. officinalis and proteins were maximum (14.89%) in S. linifolium. Aspartic, glutamic, alanine, leucine and proline were common amino acids in the three tested species. The polyunsaturated ω6 and ω3 essential fatty acids were recorded in S. linifolium (3.28%) and in U. fasciata (3.18%). The results showed that U. fasciata contained the highest amounts of lipids (2.96%), phenols (11.95mgGA/g dry wt.), flavonoid (7.04 mgCA/g dry wt.) and ascorbic acid (4.11mg/100g), respectively. β-Carotene was maximum (3940.12 IU/100 g) in C. officinalis. DPPH antioxidant activities were the highest in U. fasciata (81.3%) followed by S. linifolium (79.8%) then C. officinalis (72.6%). Among the 12 analyzed minerals, most of them were high in S. linifolium in which ion quotient ratio was the smallest (0.343). Since these algal species are common in the Egyptian coastal waters, their biochemical composition and antioxidant activities made them promising candidates for nutritional, pharmaceutical and medicinal applications.

DNA Barcoding Uncover Cryptic Diversity in Goat Fishes (Family: Mullidae) Across the Egyptian Coastal Waters.

Despite ongoing efforts to protect species and ecosystems in the egyptian costs of the Red Sea and Mediterranean Sea, habitat degradation, overfishing and pollution have posed serious challenges to marine natural resources. In spite of the accumulated knowledge on the systematics of commercial fishes in Egypt recent results suggested that we are far from having a complete picture of egyptian fish diversity. The accurate identification of species is a very important component in many fields of biological research and conservation efforts. The high level of expertise and time consuming process needed means a loss in biodiversity. Successful species identification is now frequently based on a combination of approaches including morphometrics and the sequencing of the mitochondrial COI gene known as the DNA barcoding. This study employed COI sequencing alongside traditional taxonomic identification methods and uncovered cryptic diversity within the goat fish species of Family Mullidae, four species collected from both the Red Sea and the Mediterranean Sea. Upeneus pori, Upeneus vittatus, Mullus surmuletus and Mullus barbatus samples from the Red Sea and the Mediterranean were clustered separately in a NJ tree indicating the possibility of the presence of cryptic species complex. All species could be differentiated by their COI sequence.

Benthic bloom of cyanobacteria associated with fish mortality in Alexandria waters

A survey of the potentially harmful epiphytic microalgae along the coast of Alexandria was initiated since 2005 following an incident of mass mortality of the bottom feeding fish, Siganus rivulatus in the Eastern Harbour of Alexandria. S. rivulatus is known to feed on macroalgae specially Ulva sp.A total number of 132 samples were collected seasonally along Alexandria coast, from spring 2005 to summer 2010. Six cyanobacteria species are recorded; Oscillatoria acutissima, Oscillatoria nigroviridis, Oscillatoria limosa, Oscillatoria sp., Lyngbya sp. and Planktothrix c.f. agardhii. The causative organism responsible for the massive fish mortality is O. acutissima; with a standing crop reaching 1.07×106filamentsg−1wetwt.The qualitative observations showed that Oscillatoria spp. seem to prefer green macroalgae as host to red and brown algae. The correlation between O. acutissima, O. nigroviridis and Ulva spp. showed to be significant (p=0.002). While, no significant correlation was found between the other four species and the macroalgal species tested. The two species O. acutissima and O. nigroviridis as a result, were perennial and widespread during the present study.In the Egyptian coastal waters earlier dramatic events of harmful algae occurred on several occasions due to planktonic blooms of dinoflagellates. It is the first time that fish mortality is observed due to benthic cyanobacteria particularly O. acutissima. Our current work focuses on the possible impacts of cyanobacterial species on coastal food webs.

Microbial pollution indicators along the Egyptian coastal waters of Suez and Aqaba Gulfs and Red Sea

Nowadays, the Egyptian coasts of the Aqaba and Suez Gulfs, and the Red Sea proper, are under the direct effects of many recreational resorts, urban agglomeration, marine shipping, activity of the phosphate industry, fishing ports, and limited freshwater and sewage surfaces. Therefore, the water, especially those used for recreational activities, must be of a very good quality to be able to increase the national income. To investigate the conventional water-quality bacteria, total coliforms (TC), Escherichia coli (EC), and fecal streptococci (FS), in the Egyptian coastal waters of Suez and Aqaba Gulfs and the Red Sea. A total of 2372 surface water samples were collected from 42 sampling sites during 12 years (1998-2009) to detect and estimate TC, EC, and FS using the membrane filtration method. On the basis of the national and international bacterial standards, 540 samples (22.8%) out of 2372 were found to exceed the guide values (positive samples) and were not accepted for marine recreational purposes. During the course of the study, Suez Gulf showed the highest positive records of 54 and 96 for TC and EC, respectively, whereas FS recorded 94 and 88 positive samples in the Red Sea and Suez Gulf, respectively. The lowest positive records were found in 1998 and 2009, whereas the highest were in 2000 and 2002-2004. The highest polluted sampling sites were recorded in Su7 (Suez Gulf), Aq2 (Aqaba Gulf), and Re15 (Red Sea), and were generally affected by sewage disposal and/or anthropogenic influences. The most polluted sites were in the Suez Gulf, reaching 238 sites, followed by 194 sites in the Red Sea, whereas the Aqaba Gulf had only 108 polluted sites. Moreover, the most polluted sample locations throughout the study were Su7, Aq2, and Re15, without implementation of corrective actions from authorized organizations. The data of the current study must be taken into consideration by the government for a safer and cleaner seawater in the eastern Egyptian coasts, especially those in which critical limitations in terms of microbial pollution are found.

Parasitic copepods on immigrant and native clupeid fishes caught in Egyptian coastal waters off Alexandria

Three species of parasitic copepods, one each from the siphonostomatoid families Lernanthropidae and Lernaeopodidae and one from the cyclopoid family Bomolochidae, are redescribed based on material collected from the gills of four fish species belonging to the family Clupeidae caught from coastal waters off Alexandria, Egypt. The recorded parasites are: Mitrapus oblongus (Pillai, 1964), found on Etrumeus teres (Dekay), an immigrant species from the Red Sea, and on Sardinella aurita Valenciennes, a native Mediterranean species; Clavellisa ilishae Pillai, 1962 found only on S. aurita; and Nothobomolochus fradei Marques, 1965 found on Herklotsichthys punctatus (Rüppell), an immigrant species from the Red Sea, and on Sardina pilchardus (Walbaum), a native Mediterranean species. The first two of these copepods have been reported before on clupeid hosts from the Indian Ocean. The third was known from the eastern South Atlantic and the Arabian Gulf. None of the copepods has previously been recorded in the Mediterranean. All of the parasites reported here constitute new records for these hosts. Two of the hosts are Erythrean (=Lessepsian) immigrants and were caught in Mediterranean waters off the Egyptian coast. The original description of N. fradei (Marques, 1965) is inadequate by modern standards. This species is fully described here for the first time. The male of M. oblongus was briefly described by Pillai (1964), but its mouthparts are described in detail here for the first time.

Simulation of oil spills near environmentally sensitive areas in Egyptian coastal waters

AbstractOil spills in Egyptian coastal waters have a direct impact on the national economy because of the potential environmental damage, and the corresponding negative effect on tourism. Computer simulations of oil spills were performed for four environmentally sensitive areas along Egyptian coasts using an existing oil spill model that incorporates the important variables and processes affecting oil transport in seawater. The expected slick trajectory and variation of oil properties with time were calculated for a proposed spill scenario at each site. Water current maps, the most critical model input parameter with respect to spill trajectory, were developed for each location. The simulations demonstrated that the most important oil property affecting spill response decisions and operations is the emulsion viscosity, in that it indicates when, where, and how responders can intervene for cleanup.

Adsorption-desorption of phosphate on airborne dust and riverborne particulates in East Mediterranean seawater.

The potential importance of adsorption-desorption behavior of phosphorus (P) on the East Mediterranean (E. Med) P cycle was investigated. Contrasting adsorption behavior between Saharan dust (SD) and Nile particulate matter (Nile PM) was observed. SD was a source of P to the region, which released an average of 3.3 +/- 0.3 micromolP/g into the surface seawater and showed no adsorption ability under the conditions close to the E. Med deep water. Saharan dust is therefore unlikely to be the reason for P limitation in the region. By contrast, Nile PM acted dual roles of a sink and source of P in different waters (surface seawater, deep seawater, and river water). A new crossover-type adsorption-desorption model explained the contrasting adsorption behavior and the dual nature of natural particles. The model indicates that when natural particles are transported between different waters, they can be a sink (adsorption) or a source (desorption) of phosphorus depending on the "specific concentration (lambda)", which is the ratio between the aqueous P concentration and the zero equilibrium P concentration (EPC0). EPC0 refers to the solute concentration value where the adsorption isotherm crosses over the aqueous concentration axis. When lambda > 1, adsorption occurs, whereas when lambda < 1, desorption occurs. The model added a general development to the methodology of adsorption isotherm, where, for the first time, effects of solute concentration, solid concentration, and aqueous medium (EPC0) on the adsorption and desorption of P in natural waters were simultaneously described by a single equation. Using the model, it was quantitatively reconstructed that particles emitted during the pre-1964 Nile floods could be a major source of P to Egyptian coastal waters (up to 4800 tonsP/yr), greater than the dissolved P flux (approximately 3200 tonsP/yr), but a trapper of dissolved phosphate in E. Med deep waters.

Changes in the Condition Index and Chemical Contents of Venerupis (decussata decussate L.) from the Egyptian Coastal Waters.

Changes in the condition index and chemical contents of adult and young aged exotic Manila Venerupis (decussata decussata L.) have been studied. Animals were collected monthly from El-Mex Bay during the period from April 1993 to April 1994. Monthly variations in total lipid, phospholipid, triglyceride, free fatty acids (FFA), phosphorus, potassium and magnesium were determined in animals of different sizes. Their average values being; 20.93%, 10.54%, 1.04%, 1.26%, 4.23 mg/g, 3.26 mg/g and 1.71 mg/g dry weight for the corresponding parameters respectively. Mostly, there was a fall in the condition index associated with considerable rise in total lipid and their constituents (Phospholipid, FFA and triglycerides). Venerupis tissues are of extremly high lipid and relatively high phospholipids, it constitutes about 49% of the roe lipid comparing to about 6% FFA and 5% triglycerides and consequently low cholestrol content. It has very low Iodine value, mostly within the average of 27.8 to 31.85, and is characterized by low density and low unsaturated lipids. Fluctuations in the lipid content of the animals followed the relative change in food intake throughout the year and the state of maturation. A marked reduction in lipid and some of its constituents was associated with lowering temperature in winter, as the result of the reduction in feeding activity. The major period of spawning occurred from June through September, and is accompanied by lipid metabolism. P and K were found to promote the growth rate and increased with increasing the condition index and showed high bioaccumulation rate, in contrast to Mg.

Abundance and diversity of surface zooplankton in the Gulf of Aqaba, Red Sea, Egypt

Surface zooplankton were studied in Egyptian coastal waters of the Gulf of Aqaba, from bimonthly samples from July 1994 to May 1995. Species diversity, numerical abundance and dynam- ics were analysed for each taxon, at six sites, inside three Protectorates. A total of 62 taxa and species were identified. At all sites, copepods were predominant in the standing crop with an average of 1945 ind. m~3 and formed -75.5%, numerically, of the total zooplankton community. The meroplanktonic larvae occupied the second rank and they constituted -19.7% of the total zooplankton. Seasonally, the main peak of zooplankton abundance was recorded in winter (January) with an average of 3510 ind. m~3, while September was characterized by the lowest density (1906 ind. m~3). The relatively higher diversity values were recorded at Ras Mohammed Protectorate and a progressive decline in diversity was observed northward.

Toxicity and bioaccumulation of heavy metals to some marine biota from the Egyptian coastal waters

Abstract Exposure of Isopoda (Idotea baltica) to different concentration levels of metals has enabled the identification of the mode of metal accumulation adopted by this species. The toxicity of inorganic tin was studied at different concentration levels between 1–135 ppm. The acute lethality of tin to the species was examined and found to be 24 hLCM = 96 ppm and 17 hLC50 = 115 ppm. The maximum allowable concentration of tin being 125 mg/m3 and threshold level was 1891 mg/m3. Tin was also found to hamper the growth of the animals. The toxicity and bioaccumulation of Cr, Co and Ni were studied individually and in paired and triad combinations in the animals. They showed net accumulation of dissolved metals at different concentration levels, between 1 and 150 ppm. Their toxicity increased with increasing metal concentration and exposure time, until an asymptotic was reached. Some indications of metal regulation were also observed, Laboratory results were confirmed to field conditions, and it was realized t...