الفهرس 
Chemical analysisOnly 14 pages are availabe for public view
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Abstract
Suez Bay (Egypt) is an important shipping route for oil tankers and other ships traveling through the Suez Canal. It‘s relatively shallow depth and quiet waves give it the advantage to be the main spawning and nursery ground for the most of fish population from the Gulf of Suez. Mixed pollutants are easily disposed through the direct discharge and dumping into the western boundary of the bay (studied area). The discharged waters vary from raw sewage, oil spills, and industrial effluents to garbage which has tremendous impacts on the marine environment. In general, the importance of discharged water inputs is obvious; it is a central feature in the definition of bay system. These factors are ultimately considered strong stressors on phytoplankton development. The present study is based on seasonal sampling collection during a year cycle operated at nine stations that were chosen to represent different habitats, among them a site assumed relatively less influenced by any particular pollution source is proposed a reference station. Meanwhile, a shallow fixed sampling station was occupied weekly during the productive period in autumn and winter to explore short-term variability. Weekly and seasonally changes were proved important time-scales for calculating efficiency in field study. Phytoplankton properties and accompanied seawater characteristics of this economically important marine ecosystem were the focus of the study. Generally, the bay is characterized by distinct spatial and temporal environmental heterogeneity and biological parameters as well, which might be considered to a much extent a direct impact of pollution stress. The knowledge gained, even at short-time and small-scale is essential to develop appropriate conservation and management strategies in such large ecosystem, and highlights on the priority for improved area and source of pollution for instance, and provide recommendations for the future of proposed projects aiming to improve the national economy. The study is an attempt to understand the complex abiotic-biotic interactions where these variables were monitored simultaneously. The measured abiotic regulating factors indicated the bay highly dynamic, harsh and it was hard to define a particular regulating factor. The composition and the amount of phytoplankton communities were deeply affected by environmental conditions. Water temperature reflected clear seasonality, limited regional and temporal differences during the same day of collection and surprising no signs for thermal pollution was found despite the presence of power stations for instances. Temperature as positively related with NO2 and SiO4 concentrations seems of limited direct contribution to phytoplankton abundance and community in the bay. Salinity affected by discharged water input of different origins exhibited a wide range of variation, the lowest mean salinity level at the reference station, indicating an eutrophication symptom and it seems influencing phytoplankton community structure. However, it was hard to consider salinity a useful criterion or tool for eutrophication and water quality assessment in the bay. The pH values reflect the alkaline nature of the water, except for the acidic industrial influence appeared once during the short-term collection. The pH values go in parallel with salinity variations, and a positive significant correlation was found with the dinoflagellates patchiness, which stress the pH criterion for eutrophication and water quality in the bay. The water transparency showed a sharp decrease in Secchi depth with the phytoplankton proliferation and subsequently a reduction in the depth of the euphotic zone. Despite the weak insignificant relationship between transparency and abundance and biomass variation, transparency seems to have some effects on the environmental condition as a detector of cultural eutrophication in the bay. The sea water Summary 314 was well oxygenated, explaining ―fair/poor‖ and ―good/fair status, and hypoxia events never occur. However, the extreme dissolved oxygen (DO) values observed irregularly during the short-term sampling indicate the bay faces ecological risk, needs quick improvement. The variations in Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) gave uncertain results about organic pollution in the bay. However, the inverse correlation found between DO and BOD indicates degradation of the organic matter, and the BOD:COD ratio was found to be reliable and useful indicator to relate organic matter content in the bay waters. The nutrients dynamics impacted phytoplankton structure and production and its influence in eutrophication development and pressure water quality assessment was obvious. Discharged run-off from different sources greatly affected the chemical composition of the water drove the system towards eutrophication. The study at different stations of different environmental characters declares clearly influence of anthropogenic eutrophication pressure and degradation of seawater quality that modulated the structural properties of the phytoplankton assemblages, heterogeneous temporal and regional patterns of community structure, diversity, abundance, and biomass. The concentration of available nutrients seems one of the decisive factors controlling phytoplankton growth. However, for different reasons the solo monitoring of nutrient levels was not solely effective in quantifying anthropogenic pressure. Ammonia was by far the most abundant form of inorganic nitrogen, and phosphate was potentially limiting to abundance and biomass relative to nitrogen. The ratio continuously fluctuated in the bay and represents a potential variable to assess eutrophication and expresses the power of multifactor on community structure. The calculated values according to Karydis et al. (1983) of nutrient eutrophication index (I) based on annual mean of NH4, NO3 and PO4 indicate mesotrophic condition for the three nutrient elements at most of the stations, and the oligotrophic Summary 315 status was very limited in time and space. The total annual mean value of the present heavy metals concentrations in Suez Bay increased to almost double value recorded by Hamed et al. (2003). The metals concentration could be arranged in the following sequence: iron > zinc > copper > lead > nickel > cadmium > manganese> chromium, in partial agreement with the previous author. Based on the total load of the eight metals, the seasons could be arranged in the following sequence: spring >summer >winter >autumn.