Comparative Study on Plankton Abundance and Diversity among the Three Villages of Southwest Region in Bangladesh

Abstract

The study was conducted at the water bodies of three villages namely Southkhali, Nolian and Southkadamtala located near the coastal belt of Sundarban mangrove forest to compare abundance and diversity of phytoplankton and zooplankton among the three villages and between the inside and outside of the embankment. In each village plankton samples were collected from three study areas both the inside and outside of the embankment. A total of32 phytoplankton species from outside of the embankment and 25 species from inside of the embankment were identified. The identified phytoplanktons were under the class Chlorophyceae, Bacillariophyceae, Cyanophyceae, Dinophyceae and Euglenophyceae. Among them Bacillariophyceae was the most dominant class (44.13%). The average phytoplankton abundance was varied from 480 to 2630 ind/I Phytoplankton abundance was most dominant in Southkadamtala study area (2630 ind/I) and lowest (480 ind/I) in Nolian study area. In case of zooplankton, a total of 27 species from outside of the embankment and 20 species from inside of the embankment were identified. The identified zooplanktons were under the class Rotifera, Copepoda, Branchiopoda, Bivalvia, Crustacea, Hydrozoa, Polycheate and Clitellata. Among the classes, Copepoda was the most abundant (56.25% ). The average zooplankton abundance varied from 600 to 1908 ind/I. Plankton abundance was recorded highest in inside of the embankment except Southkadamtala. Among the study areas Southkhali study area both outside and inside of the embankment was most diversified for both phytoplankton and zooplankton. Diversity indices such as Shannon-Wiener diversity (H) ranged from 1.86 to 2.69 whereas evenness (J) ranged from .86 to .99, Simpson's diversity (D) ranged from .048 to .169, Margalef index (Da) ranged from 1.46 to 5.05, Menhinicks index (Dmn) ranged from 1.3 to 3.25 in the study areas. According to the diversity index, plankton diversity in the study areas were moderately high. The information obtained from this study can contribute for planning in conducting further research. In addition, the study can also help to manage the aquatic ecosystem.