The quantitative survey of Bacierioplankton In Anzali Lagoon Water (50 stations) was accomplished in a few month period with attention to physical, chemical and biological specifictions, so as to be able to use the results as the indicator for trophic quality assessment of the lagoon. During the measurment the average number of the bacterioplankton in the lagoon was 5.76 million / cm3 and the alteration range in different areas was between 4_10 and 7.69 million 1 cm3. The areas containing much planktonic and macrophytic plants or more organic compounds, had more abundant bacterioplankton. The obtained values for the bacterioplankton in this study is specifically for abundant hydrological ecosystems, and the number of the bacterioplankton shows the eutrophy of the Anzali Lagoon in compare with hydrologocal environments of the other districts, specially the temperate districts......
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