Analysing the physicochemical dynamics and biodiversity patterns in bhimtal, nainital, and Sariyatal lakes

Abstract Lakes, as essential lentic ecosystems, undergo dynamic changes influenced by exogenic factors. The delicate balance of lakes is prone to disruption due to various factors. Therefore, it is of paramount significance that these crucial ecosystems are studied thoroughly. The present study delves into the physicochemical properties-temperature, pH, dissolved oxygen, conductivity, total dissolved solids, and transparency- along with diversity indices such as Shannon-Wiener diversity, Pielou’s evenness, and species richness, based on phytoplankton, in three candidate lakes of the Kumaun region i.e., Nainital, Bhimtal, and Sadiyatal. A comparative analysis was done for littoral and limnetic zones for the ecological indices by utilizing PCA to unveil potential similarities among the lakes. Results highlight distinct dissimilarities, rooted in geography, and altitude. Unexpectedly high temperatures and low dissolved oxygen is observed in Nainital while Bhimtal represents resilience due to its relatively large size and better transparency. Sadiyatal is observed thriving with highest species richness possibly due minimal human interventions. Littoral zones exhibited higher species diversity, driven by nutrient availability and macrophyte interactions, whereas the limnetic zone was dominated by planktonic species adapted to open-water conditions. This study presents novel insights into the intricate interactions between physicochemical attributes and phytoplankton dynamics, significantly advancing the understanding of these lake ecosystems.