الفهرس | Only 14 pages are availabe for public view |
Abstract Plants including algae respond quickly to environmental changes and hence their growth and species composition are more likely to indicate the quality of water mass in which they are found (Gannon and Stemberger, 1978 and Gharib 1998). Aquatic ecosystems may exhibit variable physical and chemical characteristics and consequently variable pbytoplanktonic composition. I. The increase of nutrients (especially nitrogen and phosphorous) in water bodies may be the main factors for increasing eutrophication (Rast and Lee 1978; Round 1981; Kobbia 1982; Stirm 1988; Galal 1989; Chisholm 1992 and Abdallah et al1995 a and b). However eutrophication of water bodies was accelerated by the discharge of domestic and industrial efiluents (prased 1982; Umamaheswara Roa & Mohanch and 1988 and EI-Sherif 1993 a and b). Variation in nutrient concentration not only affect the growth and species composition of phytoplankton but also has a marked effect on the biochemical composition as indicated by Sakshaug (1977); Barlow (1980); El-Sherif (1993b) and Abdallah et al (1995b). When sufficient nutrients are available the chlorophyll, ATP & protein carbohydrate ratios are high due to the active production of chlorophyll a, A TP & protein (Barlow 1982). |