Study of Zooplankton communities and its relation to some physicochemical parameters Karoon 4 reservoir

This study was located at Karoon 4 reservoir, down-stream of Armand and Bazoft rivers (Southwest of Iran). Water samples were collected from March 2012 to February 2013 in three selected silts. Environmental parameters and chlorophyll a concentration were measured, as well as identification and abundance of zooplankton communities was studied. According to this study, 4 phyla of zooplankton was identified, include Rotifera, Protozoa, Cladocera and Copepoda. Overall 43 species were identified at four seasons. Most abundance was related to the phyla Rotifera (27 species), Copepoda (7 species), Cladocera (5 species) and Protozoa (4 species) respectively. The results showed, the maximum rate of chlorophyll a concentration was measured in the warm and minimum of this, was measured in the cold months. Al groups of zooplankton phyla without copepod, showed the minimum abundance at winter. The rate of chlorophyll a concentration, amount of phosphate and zooplankton indicator species, showed an oligotrophic condition in the lake of karoon 4 dam. As the results, we have the positive significant correlate between all groups of zooplanktons abundance and temperature, as well as chlorophyll a concentration (P<0.01). Whereas, there is negative correlation and not significant between DO and zooplankton communities (P>0.05).