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vol-35EPIPELIC AND PHYTOPLANKTON ASSEMBLAGES CLOSE TO
TWO NILE ISLETS AT GREAT CAIRO
MOHAMAD SAAD ABD EL-KARIM
National Institute of Oceanography and Fisheries
Keywords: Epipelic, Phytoplankton, Environmental characters, Nile islet,
ABSTRACT
The epipelon and phytoplankton at two Nile islets were seasonally samples during
2007. Four stations two more human impacted and two less impacted at El-Zahb and ElWaraq islet were sampled. The epipelic microalgae were more regular in their distribution
compared with phytoplankton between the more nad less impacted stations. Total epipelon,
different groups and diversity were negatively correlated with TP during winter, whereas
density of total epipelon and diatoms were negatively correlated with TP during autumn but
with less intensity compared with winter. The phytoplankton assemblages showed high
significant positive correlation with the different nutrient salts throughout the year. This
response of phytoplankton communities towards these conditions in spite of their high
increase indicated that this disturbance still in the intermediate strength that can not damage
the phytoplankton populations. The microalgal diversity and abundance were compared
with corresponding values at two reference sites at the River Nile mouth at Aswan. In
average, biodiversity index was lower than the corresponding values at both reference sites.
The Ecological Quality Ratio (EQR) resulted in the ratio of 0.76 which indicated an
Ecological status of good level. On the other hand, based on the phytoplankton abundance,
EQR were 6.8 and 10.4 for the River Nile at Aswan City and Aswan Reservoir,
respectively, these ratios revealed a poor ecological status.
