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vol-26IMPACT OF POLLUTION ON PHYTOPlANKTON COMMUNITY
STRUCTURE Il\’ lAKE EDKU, EGYPT.
By
ZAGHLOUL, F. A. * and HUSSEIN, N. R.
*National Institute ojOceanography and Fisheries Alexandria. Eg;pt.
Key words: Ph~1oplank”1on,Diyersity, Habitat structure relationship. Lake Edk”U.
ABSTRACT
Phytoplankton community structure, diversity index and some hydrographic
conditions were investigated seasonally in Lake Edku during the year 2000.
Results showed that the studied area is considered to be eutrophic. Levels of
nutrients measured are all significantly higher than those found in the same area
in the last few years.
A total of 61 species were identified comprising 15 Chlorophyceae which
formed 553% by number to the total phytoplankton standing crop, 25
Bacillariophyceae (33.7%), 8 Euglenophyceae (8.8°;’0), 11 Cyanobacteria (1.9%)
and 2 Dinophyceae (0.3%). The dominant species was the chlorophycean
Carteria sp., (a new record for the lake), which contributed 47.0% by number to
the total phytoplankton standing crop, Nitzschia spp. (14.8%) and Cyclotella
meneghiniana (12. 1%).
The phytoplankton standing crop in Lake Edku during the year 2000 showed
a remarkable decrease as compared with the previous records (in 1995-1996l.
Furthermore the present study has indicated high level of eutrophication,
accompanying the change in community composition and dominance, as
Chlorophyceae became predominant instead ofBacillariophyceae
