MONTHLY VARIATIONS OF THE EPIPELIC AGAL COMMUNITIESIN AL-AaRAS TOURIST ISLAND LAKE , BAGHDAD - IRAQ

Abstract

Three sites at the Al-aaras tourist island lake were selected to study the physicochemical
characters and epipelic algal communities . Monthly samples for 12 month
were taken starting January 2009 . It was found that the lake is alkaline , well
oxygenated ,oligohaline with low electrical conductivity and hard water . The
concentration of reactive nitrite ( NO3) were available and low concentration of
reactive phosphate ( PO 4 ) . A total of 67 taxa were identified dominated by
Bacillariophyceae ( 65.7 % ) followed by Cyanophyceae ( 16.4 % ) and
Chlorophyceae ( 13.4 % ) . Clear seasonal variations in the total density of epipelic
algae were found at different studied sites with a binomial pattern at spring and
autumn . The total cell number was ranged between 0.09 x 10 4 – 14.0 x 10 4 Cell
/ cm² . Almost similar binomial peaks also found in Bacillariophyceae , out of 11
taxa identified of Cyanophyceae , 6 were belong to Oscillatoria . While
Scenedesmus quadricauda was composed of high cell number of Chlorophyceae .