Study of Limnological Status of Two Selected Floodplain Wetlands of West Bengal

Abstract

Limnology is the study of all aquatic systems, both lentic and lotic fresh, fresh, and saline including lakes, wetlands, marshes, bogs, ponds, reservoirs, streams, rivers, oceans, etc. about their physical, chemical, and biological characteristics. Among this phytoplankton, Zooplankton, periphyton, benthos are a minute aquatic free-floating microscopic organism, which acts as a larger food source of larval and higher vertebrates and invertebrates including carnivorous and omnivorous fishes. They are related to the growth of juvenile fishes and are also play important role in the transfer of energy from the primary phytoplankton to higher trophic levels. The plankton community fluctuates according to the physicochemical parameters and the relative environment of the water body especially the Rotifers as they are known to change immediately along with the change in water quality . Realizing the importance of floodplain wetlands and the paucity of literature on the limnology of this ecosystem present investigation was carried out in two floodplain wetlands having characteristics of open (Kole beel, an ox-bow lake formed near Somra Bazar in Hooghly district), and closed beel Suguna beel situated in Nadia District of West Bengal) system during the period 2011–2013. The physicochemical parameters of the investigated beels' water and soil were, for the most part, favorable for planktonic development. It has an alkaline pH of 7.5–8.4 and is alkaline. The dissolved oxygen content and Secchi Disc transparency values indicate that the water is in excellent condition. The water was moderately hard, with only trace amounts of nutrients present. Seasonal fluctuations in the water column were apparent, and they were mainly attributable to replenished supplies and volume. The plankton population of the studied ecosystem was made up of a mixed and healthy population of diverse fauna. The greatest diversity was observed during the winter season, when favorable temperature, dissolved oxygen, and other physicochemical parameters of water, as well as optimal solar penetration, coincided. In a closed system (Suguna), the richness of planktonic structure resulted in higher fish production (1570.05 kg/ha/yr) than in an open system (Kole) (384.4 kg/ha/yr). The status of floodplain wetlands was determined to be eutrophic based on various Physico-chemical and biological parameters.

Zooplankton Productivity Evaluation of Lentic and Lotic Ecosystem

“…The zooplankton community is quite susceptible to changes in the environment. Therefore, they are of ecological relevance because changes in their abundance, species diversity, or community composition can give key signs of environmental change or disturbance [10].…”

“…Limnology is the study of all aquatic systems, both lentic and lotic fresh, fresh, and saline including lakes, wetlands, marshes, bogs, ponds, reservoirs, streams, rivers, oceans, etc. about their physical, chemical, and biological characteristics [10].…”

“…Primary productivity is inversely related to the nutrient concentration, indicating that when the nutrient status is low, both primary productivity and fish output decline. There is only one primary production peak in reservoirs during the summer or early summer, according to numerous researchers who have examined the primary productivity of water bodies in different places and at different times of the year [10].…”

Comparative analysis of bloom phytoplankton community composition and environmental factors in selected lentic ecosystems of Assam, India

“…The changes in the faunal community are caused by changes in the quality of water in the floodplain. Fish and primary production suffers from a lack of nutrition (Ziauddin, 2021). Wetlands near rivers, for example, control phytoplankton productivity, which is the foundation of the trophic chain and indicates water quality.…”