Spatial and Temporal Variations of Phytoplankton Communities and Environmental Conditions Along the Coastal Area of Alexandria

Abstract

This paper studied the spatial and temporal variations of phytoplankton communities and environmental conditions. This study focuses on the Spatio-temporal distribution of phytoplankton community structure and environmental conditions (physical conditions, and nutrient availability) along Alexandria coastal area (from Abu Qir in the east to eastern harbor in the west) over one year 2013-2014. The study results gave a signal of the area is light to moderate polluted and emphasized the need of use phytoplankton community as index of water quality. A total of 153 phytoplankton taxa were identified belonging to73 genera (6 Classes); Bacillariophyceae, Dinophyceae, Cyanophyceae, Chlorophyceae, Euglenophyceae and Silicoflagellata. Bacillariophyceae recorded the main bulk, while the others were limited and showed an indication of pollution. The total average density (60.7x103units l-1) was mainly a reflection of the trends in counts of Bacillariophyceae (58.03x103units l-1). Species diversity (H’) ranged between 0.21 and 3.59. The most obvious impact of the previously described physical and chemical features is on the distribution of phytoplankton biomass derived from Chl-a concentration (ranged; 0.92-4.27µgL-1). The concentrations of the nutrient salts displayed significant seasonal variation. The results revealed that the values of salinity, DO, temperature and pH were in the ranges: from (35.34 to 38.28 ‰), (4.77 and 11.13 mgl-1), (18.20 and 27.5 °C), and (7.53 to 8.12), respectively In general, the results indicated that the amounts of ammonia decreased as follows: winter < spring < autumn < summer (ranged; 0.14-5.16 µM), while nitrate were as follows: spring < autumn < summer < winter (ranged; 3.69 -19.66 µM), and the PO4-P content were arranged as follows: spring < autumn < winter < summer (ranged; 0.13 -0.79 µM).