Seasonal variation in diversity, abundance and assemblage pattern of phytoplankton influenced by hydrological parameters in a seasonally open subtropical wetland of India

Abstract

The study aims to investigate the seasonal variations of phytoplankton in Kitaman tal (wetland) in Kushinagar district, Uttar Pradesh, India. Between 2021 and 2023, a thorough analysis identified 121 phytoplankton species. The species were categorised into six phyla, including Bacillariophyta, Charophyta, Chlorophyta, Cryptista, Cyanobacteriophyta, and Euglenophyta. Species richness was highest in the summer season, followed by the monsoon and winter seasons. The seasonal variations in density ranged from 3.25 x 105 to 1.78 x 106 in summer, 3.99 x 105 to 5.48 x 106 in monsoon, and 3.36 x 105 to 4.14 x 106 in winter. The monsoon season had the lowest density, while the summer season had the highest density. Water temperature, pH, Cl-, dissolved oxygen, specific conductivity, total dissolved solids, silicate, and chl-a varied significantly (p < 0.05) across different seasons. The Redundancy Analysis (RDA) model revealed a positive influence of Bacillariophyta and the overall phytoplankton by dissolved organic matter, phosphate, and silicate. Kitaman Tal has a rich diversity of phytoplankton, supporting important fisheries vital to the livelihoods of fishermen.