الفهرس 
Introduction
Effect on phytoplankton speciesOnly 14 pages are availabe for public view
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Abstract
While phytoplankton are primary producers and play an important role in the food chain, the present investigation comprises the effect of environmental conditions as well as the stimulatory and inhibitory actions of some selected macrophytes on phytoplankton communities inhabiting the area of study at El- Quanater El Khayria (River Nile, Egypt) were studied
Physico-chemical chracteristics:
During the period of investigation the changes in air and water temperature take place in a wide range. The highest air temperature value 34.9 ± 0.07 °C was recorded during summer at site 4 and the lowest value 18.40 ± 0.00°C was recorded in winter at the same site. The maximum value of water temperature (31.50 ± 0.07 °C) was recorded in summer at site 3, while the minimum (14.8 ± 0.14 °C) was recorded in
winter samples at site 2. pH values decreased to a minimum 6.93 during spring at site
3 and started to increase again during summer reached 8.48 at site 4. The highest electrical conductivity values were recorded in winter (ranged between 342.00 ± 2.83 at site 4 and 326.50 ±2.12 µmohs at site 3), while the minimum value of 123.50 ± 0.71
µmohs was recorded during spring at site 4. The depths ranged from a maximum of
2.50 ± 0.00 m at site 4 in winter to a minimum of 0.85 ± 0.07 m at site 2 in spring. The maximum values of Secchi depth were recorded at site 1 in autumn, while the minimum value was found at site 2 in spring. The lowest value of dissolved oxygen of
5.04 ± 0.02 mgL-1 was recorded in summer at site 2 and the highest value 12.08 ± 0.11 mgL-1 in autumn at site 3. Carbonate was not present during autumn and winter in all samples collected from site 1, 2 and 4. Bicarbonate contents increased in spring
compared with the situation in the other seasons. Ammonium (NH4 - N) values ranged between a minimum of 23.91 ± 0.06 µgL-1 at site 1 in spring and a maximum of 75.67
± 15.20 µgL-1 at site 4 in summer. The highest nitrite value of 16.59 ± 0.16 µgL-1 was recorded at site 3 in summer, while the lowest nitrite value of 10.29 ± 0.03 µgL-1 at site 1 in winter. The maximum nitrate value of 391.58±0.53 µgL-1 was observed at sit 3 during winter, while its lowest value of 43.57±8.73 µgL-1 was recorded at site 4 in
spring. Orthophosphate values varied from a minimum of 17.97±0.36 µgL-1 at site 3
(during autumn) to a maximum of 129.74± 0.56 µgL-1 at site 2 (during winter).
The Silicate values fluctuated between 0.32 ± 0.05 mgL-1 (at site 1 during summer) and 1.17 ± 0.09 mgL-1 ( at site 2 during the same season).e