Water Quality and Pollution Dynamics in Freshwater Ecosystems Under Climate Change

Freshwater systems are critically endangered by a synergy of increasing anthropogenic stress and climate-induced vulnerability. The objective of this study was to assess this critical feedback loop that will exacerbate the rate and magnitude of pollutant loading into the aquatic ecosystem as temperature rises and precipitation regimes are disrupted. Increased water temperatures have decreased the solubility of oxygen while at the same time increasing microbial metabolic rates, which, combined with episodic extreme hydrology, would then flush industrial and agricultural pollutants into the waterway much faster than they can be naturally buffered. It investigated this feedback in the Cauvery River Basin, Southern India, through three years of regular sampling from 12 stations and monitoring levels of nitrogen, phosphorus, and dissolved oxygen, and related these measurements to climate fluctuations. It found that precipitation intensity caused by climatic factors is the most sensitive predictor of pollutant loading, especially in the downstream, anthropogenically loaded urbanized regions. This demonstrates a potentially irreversible trend in degradation and endangerment to the fisheries, biodiversity, and human water resources of the basin, demanding intervention. As such, it proposes that the implementation of climate-adaptive infrastructure for existing water quality monitoring will ameliorate these pulse loadings. Stakeholders who consider their local basins within the context of larger Sustainable Development Goals will increase resilience to the ever-increasing fluctuations of the climate and increase their system’s ability to provide vital services to people who have become critically dependent on them in the most vulnerable environments globally.