Water quality assessments of the river Gorveshwari in Dinajpur, Bangladesh

A study was carried out to assess planktonic community with some physico-chemical parameters of the Gorveshwari river in Dinajpur district of Bangladesh. Fortnight water samplings were performed at four sites. Findings revealed that water temperature, water level and transparency were within the optimal ranges- 14.33-31.23°C, 1.38-3.97 m and 43.32- 88.67cm respectively. The values of dissolved oxygen, pH, total alkalinity and total dissolved solids were found to vary 7.16 -9.32 ppm, 6.37-8.93, 28.07- 39.56 ppm and 59.87-133.74 ppm in the four sampling sites respectively. From plankton analysis, 36 genera of plankton were identified of which 27 genera were phytoplankton groups and 9 genera were zooplankton. Among them, Chlorophyceae ranked the first position with highest abundance 3.11±0.12×103cells/L. Euglenophyceae was recorded as the minor group of phytoplankton both in number and density. On the other hand, abundance of Rotifera was found to be higher in number (0.95±0.04×103cells/L), while, Crustacean larvae was noticed as scarcer group throughout the study period. Moreover, from correlation analysis it was observed that the abundance of total phytoplankton and total plankton were negatively correlated with water temperature and transparency where positively correlated with water level, pH, dissolved oxygen, total dissolved solids and total alkalinity. This study concludes that the fish production suitability of Gorveshwari river is within productive range though some anthropogenic activities affecting the aquatic biodiversity were also observed throughout the sampling period.