Evaluation of vertical and horizontal changes in community structure of zooplankton in a deep dam lake


Abstract: The purpose of this study was to describe the horizontal and vertical distributions of the zooplankton community structure in Karakaya Dam Lake. Rotifers were numerically dominant (81.89%) in the community during the study period; they were followed by Copepoda (10.32%) and Cladocera (7.79%). In the metalimnetic maximum oxygen zone between 5 and 10 m, cladocerans made up 70.1% of the total number of zooplankton in June and 27.3% of the total number of zooplankton in November. Oxygen values decreased at 10 and 15 m in September and November. While the abundance of rotifers and cladocerans decreased as well, cyclopoids increased (60% of total zooplankton at 10 m). Nitrogen and soluble reactive phosphate were at low concentrations. Relationships among zooplankton, abundance, and environmental factors were analyzed using the unweighted pair-group method using arithmetic averages (UPGMA) and canonical correspondence analysis (CCA). UPGMA cluster analysis was used to illustrate unimodal species distribution by classification into 2 groups. Eigenvalues of axes clarified 42.7% of the cumulative variance in species data and 62.9% of the relationship between species and environmental data in the CCA. Many zooplankton species, rather tolerant to different environmental conditions, are good indicators for water quality and can be used for the biomonitoring of water ecosystems.

Keywords: Canonic ordination, spatial distribution, population dynamics, water quality, Karakaya Dam Lake, upper Euphrates River

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