Water Quality Analysis and Its Impact on Biodiversity in Freshwater Ecosystems

Abstract

Freshwater ecosystems are among the most biodiverse and vulnerable habitats on Earth, yet they are increasingly threatened by pollution and declining water quality. This study investigates the relationship between key water quality parameters and aquatic biodiversity in five freshwater sites with varying degrees of anthropogenic disturbance. Utilizing a quantitative, field-based approach, the research measures physicochemical indicators such as dissolved oxygen (DO), biological oxygen demand (BOD), pH, turbidity, nitrate, phosphate, and heavy metal concentrations, alongside biological assessments of phytoplankton, zooplankton, and benthic macroinvertebrates. Results reveal a strong positive correlation between DO and species richness, while high levels of BOD, nitrate, and heavy metals are significantly associated with reduced biodiversity and the dominance of pollution-tolerant species. Statistical analyses, including correlation tests, Principal Component Analysis (PCA), and Cluster Analysis, further confirm the influence of water quality on community structure. The study concludes that degraded water quality directly compromises freshwater biodiversity and ecosystem function. It emphasizes the importance of integrated watershed management, ecological monitoring, and policy enforcement to protect aquatic life and ensure long-term ecological sustainability.