Assessment of distribution and abundance of phytoplankton communities in Atrak River- North Khorasan Province
Subject Areas : New Technologies in Aquaculture Development
Keywords: Phytoplankton, Atrak River, Keywords: Ecology, North Khorasan Province,
Abstract :
Abstract Present study is carried out in 10 sampling sites from July 2007 to June 2008. Sampling stations were chosen according to the result of the Atrak River survey that was done along the river before the study gets started. Samples were collected twice per month from each site. 100 lit of water were filtered with plankton net (20 µ mesh size). The phytoplankton that were identified from samples are as follows: Chlorella, Stigeoclonium, Ankistrodesmus, Closterium, Gyrosigma, Eremosphara, Oscillatoria, Anabaena, Chlamydomonas, Diatoma, Nitzschia, Navicula, Oocystis, Meridion. Results indicate that Chlorella had the most frequency (n=1055) and Meridion had the least (n=120). Also sampling site number 6 (Najaf-abad Dam) had the highest phytoplankton frequency (n=753) and sampling station number 3 had the minimum (n=389). Overall, the results demonstrate a low diversity of phytoplankton and also low number of specimens in total sampling (n=5852). Therefore, one can come to conclusion that the population of phytoplankton in the Atrak River from the density and frequency point of view is not considerable.
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