Benthic Diatom as an Indicator for River Health Assessment in Vindhyan Lotic Ecosystem, Central India

Abstract

The health of the ecosystem of a central Indian river from the Neolithic era was evaluated. The Belan River, approximately 180 km long and in the pristine north-central region of the Vindhyan ranges, was sampled seasonally at five distinct stations from November 2021 to October 2022. Diatom samples were collected by scraping a 3x3 cm area of substratum (stones) to a depth of 30.48 cm. The most abundant taxa observed at Station S1 were Aulacoseira granulata, Cymbella affinis, and C. tumida in winter, summer, and monsoon seasons, respectively. At Station S2, C. affinis was the predominant taxon only during summer, with none detected in the winter or monsoon seasons. At Station S3, Navicula radiosa and Melosira varians were the most abundant taxa in winter and summer, respectively, with no presence in the monsoon season. The prevalent taxa varied at Stations S3 and S4 as well. Characteristic variations of taxa were noted across different stations and seasons. Cluster analysis revealed that S1 and S2 were grouped as upper zones, while S4 and S5 were categorised as lower zones, with S3 being distinctly separate. The health assessment indicated that the river was either minimally polluted or not polluted at most stations, suggesting that it remains pristine, mainly due to the sparse human settlement and absence of industrial development along its length.