الفهرس 
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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).