Spatial and temporal pattern of zooplankton assemblage in response to Limnological factors of river, Yamuna

Abstract

Zooplankton plays a key role in maintaining aquatic ecosystem quality and is closely related with the community structure. During the present investigation, the zooplankton samples were collected from the three different sampling stations of River Yamuna for a period of one year from April 2012 to March 2013. The physico-chemical parameters of water such as temperature, transparency, velocity, turbidity, conductivity, pH, total alkalinity, total hardness, calcium, magnesium, dissolved oxygen, biological oxygen demand, phosphate and nitrate. The temperature ranged from 17.0±2.59 oC to 18.58±2.90oC and pH showed slightly alkaline nature. Sampling station, I registered a maximum dissolved oxygen concentration of 11.41±0.775 mg/l and minimum nutrient concentration. A total of 29 genera of zooplankton belonged to four different taxonomic groups were identified. Among these 10 genera belonged to protozoa, 11 genera belonged to rotifera, 6 genera belonged to copepod and 2 genera belonged to ostracoda. The zooplankton density was highest at sampling site I with maximum number of individuals belonging to all the four group. Rotifera formed the dominant group followed protozoa, copepoda and ostracoda. Daphnia, Asplanchna and Paramecium was reported with highest number of individuals during the entire study period. The total zooplanktonic richness generally indicated favorable environmental conditions and these were characterized by tolerant of widely fluctuating environmental conditions. Pearson correlation coefficient and Shannon- Weiner diversity index (H’) was calculated.