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Spatial and seasonal variations in the nutritional composition of the dominant seaweed species were assessed at three sites during 2017 from Hurghada and Safaga of the Red Sea coast. Results showed that six species were dominant and had the highest coverage during the year of study. The proximate composition of these seaweeds showed as a significant difference among sites and seasons and the correlation with the environmental parameters were established. Total carbohydrates were higher and more varied among seasons (12.1- 41.9% dry wt.). Carbohydrate levels were positively correlated with seawater temperature, pH value, and salinity. Total soluble protein of these seaweeds was varied significantly between seasons (3.2-8.3 % dry wt.) with the highest values in winter while there is no a significant difference between the sites. The protein levels were positively correlated with dissolved nitrate and silicate but negatively correlated with water temperature. Total lipid content of the tested seaweeds was varied between 1.1 % dry wt. during winter and 0.6 % dry wt. during spring and it was significantly correlated with nitrite and pH value. Fibers content of the tested seaweeds were varied among the sites and seasons (26.5-53.5 % dry wt.). While, Ash content was not varied among the sites and seasons.

This study aims to provide a recent seabed characteristic of ridges along the eastern coast of Alexandria on the Egyptian Mediterranean Sea. Side scan sonar was used for acoustic imaging and Quester Tangent Corporation (QTC) VIEW for acoustic signal survey. ROV was applied to detailed video survey and sediment sampling to provide ground truth data. The integration between acoustic signal classes and the acoustic images can divided the study area into three acoustic categories; 1) weak backscatter corresponds to very fine sand to silt sediments, 2) strong backscatter confined to coarse to medium sand, and 3) isolated reflections, which appear widespread along the whole study area and represent two discrete parallel discontinuous hard limestone ridges. These discrete parallel ridges are found to be trending parallel to the coastline. A seabed feature map for the study area is obtained from the integration of output results of side scan sonar backscatter analysis with the QTC acoustic classification and ground-truthing using ROV and grab sampler. The high resolution of acoustic image help to detect the variation of the wavelength and amplitude of sand ripples in the study area. Keywords: Mediterranean Sea, Alexandria coast, Acoustic survey, Side scan sonar, Seabed features, Backscatter

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 physico-chemical 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.

This review describes the phytoplankton species in the Egyptian waters of the Red Sea and some surrounding habitats namely; Gulf of Suez, Aqaba Gulf and Suez Canal as well as the species abundance during the period from 1990 to 2010. Although many reviews on the phytoplankton species had been done for some areas of the world, a clear and concise list of the phytoplankton species for Red Sea waters (Egypt) has recently not documented. Aim of this Review: This review aims to provide a checklist of phytoplankton species found as their names and abundance appear in the cited literature, as well as their current valid, accepted names and their common synonyms. This will allow for a better understanding of the presumed phytoplankton species documented around the areas of Red Sea waters (Egypt). Place and Duration of Study: The phytoplankton species reported in this review are collected from the different published sources that represent the years spanning 19902010.

Phytoplankton community structure and some environmental parameters in the coastal water of the north western part of the Red Sea were studied seasonally during 2013. A total of 145 species were recorded with clear dominance of Bacillariophyceae, which formed about 76.4% of the total phytoplankton counts with annual average of 3654 cell/L and Dinophyceae (14.63%) with annual average of 700 cell/L. Other algal classes; like Cyanophyceae, Chlorophyceae, Euglenophy- ceae and Silicoflagellates sustained low counts, forming collectively about 9.0% of the total abun- dance of phytoplankton. Autumn was the most productive season recording an average of 5916 unit/L, followed by spring (average of 5282 unit/L) and winter (average of 4329 unit/L), while summer showed the lowest counts (average of 3607 unit/L). The species diversity fluctuated between 3.36 in the summer and 3.97 in autumn, with an annual average of 3.76. The physico-chemical properties of surface water exhibited seasonal and spatial variations. The dissolved nitrate (0.07-2.27 lM), ammonium (1.82-8.80 lM), reactive silicate (0.41-5.22 lM) and water salinity (39.9-42.9&) were the most effective factors that controlled the seasonal fluctuations of phytoplankton during 2013. The multiple regression model was: phytoplankton counts = 28,564 + 0.69 NO3 + 0.284 NH4 � 0.13 SiO4 � 0.30 Salinity (M.R. = 0.91, N = 24 and p < 0.07). This equation could be applied in the future to predict the total phytoplankton counts in the coastal waters of the northern part of the Red Sea, Egypt. a 2014 Hosting by Elsevier B.V. on behalf of National Institute of Oceanography and Fisheries. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Chaetoceros simplex Ostenfeld of marine diatoms was isolated and purified from the sub-surface waters of the north-western part of the Red Sea, Egypt (Hurgada). The isolated grown cells are exposed to different concentrations of nitrate and phosphate to estimate their effects on the growth and some metabolic activities of the organism. In general, the results indicated thatconcentrations of 100 μM nitrate and 5μM phosphate stimulated the algal growth by 60% and 32%, respectively in the 8 th day of culture. While, the values of 300 μM nitrate and 50 μM phosphate exhibited a decrease in the algal growth by 44% and 49%, respectively as compared with the control culture. The photosynthetic pigments (Chl-a, Chl-c and Carotenoids), total soluble proteins and carbohydrates of Chaetoceros simplex followed a similar pattern of change to that of growth in response to different treatments of nitrate and phosphate. While, the addition of different treatments of nitrate and phosphate to F/2 medium decreased the total lipids of C. simplex. Statistical analysis of the data indicated that 5 μM phosphates and 50 μM nitrates were the highly significant and most effective concentrations that positively affect most of different metabolic activities of Chaetoceros simplex . Thus, Chaetoceros simplex culture could be used as larval feed or other purposes cultured using 50 μM nitrate and 5μM phosphate .

Water samples were seasonally collected from 12 stations of the eastern coast of Suez Gulf during autumn of 2012 and winter, spring, and summer of 2013 in order to investigate phytoplankton community structure in relation to some physicochemical parameters. The study area harbored a diversified phytoplankton community (138 species), belonging to 67 genera. Four algal groups were represented and classified as Bacillariophyceae (90 species), Dinophyceae (28 species), Cyanophyceae (16 species), and Chlorophyceae (4 species). The results indicated a relative high occurrence of some species namely.; Pleurotaenium trabecula of green algae; Chaetoceros lorenzianus, Proboscia alata var. gracillima, Pseudosolenia calcar-avis, and Pseudo-nitzschia pungens of diatoms; Trichodesmium erythraeum and Pseudoanabaena limnetica of cyanophytes. Most of other algal species were fairly distributed at the selected stations of the study area. The total abundance of phytoplankton was relatively low (average of 2989 unit/L) in the eastern coast of Suez Gulf, as compared its western coast and the northern part of the Red Sea. The diversity of phytoplankton species was relatively high (2.35–3.82 nats) with an annual average of 3.22 nats in the present study. The results concluded that most of eastern coast of Suez Gulf is still healthy, relatively unpolluted, and oligotrophic area, which is clearly achieved by the low values of dissolved phosphate (0.025–0.3 μM), nitrate (0.18–1.26 μM), and dissolved ammonium (0.81–5.36 μM). Even if the occurrence of potentially harmful algae species was low, the study area should be monitored continuously. The dissolved oxygen ranged between 1.77 and 8.41 mg/L and pH values between 7.6 and 8.41. The multiple regression analysis showed that the dissolved nitrate and pH values were the most effective factors that controlled the seasonal fluctuations of phytoplankton along the eastern coast of Suez Gulf during 2012–2013.

Phytoplankton standing crop and species composition in Suez Bay were studied and discussed in relation to the environmental physico-chemical parameters during 2002-2003. A total of 80 species and varieties were recorded and identified at the selected stations of the bay'/Of them 47 species and 29 genera of diatoms; 19 species and 11 genera of dinoflagellat es; seven species of cyanophytes within four genera; six species of chlorophytes among four genera and one species of chrysophytes. Two main phytoplankton peaks were recorded during spring and autumn seasons (average of 15,676 and 15,376 unit.!/1 respectively). The diatom species responsible of these peaks were, Nitzschia pungens var. atlantica, Asierionellajapomca, Skeletonema costatum, Chaetoceros decipiens and Gyrosigma attenuatitm. The species diversity showed a minimum value at the sewage treating company (ABB station) ranging from 2.17-3.36 nats. While, the highest diversity values were recorded at the unpolluted station, Aiyoon Mousa (VI) and varied from 2.74-3.61 nats. The results revealed regional and seasonal inverse correlation between diversity and phytoplankton standing crop in Suez Bay and it is regarded as a pollution habitat. The results of N:P ratio indicated that Suez Bay is generally P-limited, mainly due to the high load of nitrogenous compounds specially ammonia, which formed about 60.7:1 % of the total inorganic nitrogen, followed by nitrate (33.7 %) and:nitrite (5.57 %). Dissolved inorganic phosphate recorded with annual average of 0.98 pmoIX"1. Generally, the level of nutrient salts indicated that Suez Bay is in the eutrophic state.

Surface water and phytoplankton samples were seasonally collected from different 18 stations covering about nine harbors along the Northern Red Sea during 2014-2015. The phytoplankton community was represented by 146 species belonging to 57 genera. These species are classified as 86 species of diatoms, 39 dinoflagellates, 15 cyanophytes, three of euglenophytes, two species of chlorophytes and one of silicoflagellates. The diatoms were the leading and most dominated group, forming about 81 % of the total phytoplankton abundance. The highest occurrence of phytoplankton was observed at the stations and harbors near the northern part of the Suez Gulf (Suez Bay), due to the partial treated sewage discharged from ABB Company, and low fractions of petroleum hydrocarbons derived from some petroleum companies. Whereas, other harbors located in the Gulf of Aqaba and eastern coast of Suez Gulf were the lowest productive sites. The highest abundance of phytoplankton during winter, 2015 was associated with highest values of dissolved oxygen (3.35-10.39 mgO 2 /l) and dissolved nitrate (0.170 -1.262 µmole/l). The species diversity of phytoplankton (annual average of 2.47 nats) showed its minimum during spring at Adabiya inside harbor, which may reflect a relative high pollution state at this area. The stepwise multiple regression analysis revealed that mainly dissolved nitrate followed by water temperature and pH values were the most effective variables that controlled the seasonal fluctuations of phytoplankton at the different sites of the study area during 2014-2015. However, the existence of some toxic phytoplankton species in the present study suggests careful consumption of fisheries resources at the different harbors of the study area and frequent monitoring for Harmful Algal Blooms (HABs) is required.