Exploring water quality and pCO2 dynamics in major rivers of Uttarakhand, India

Rivers receive substantial amounts of organic carbon from adjacent terrestrial areas, transforming into carbon dioxide (CO₂) emissions and contributing to global warming and climate change. The riverine emissions are discussed globally and yet less explored. Notably, anthropogenic land use can influence riverine CO₂ emissions, leading to significant uncertainty in estimation. With the increased rates of population and industries, the GHG emissions from rivers are expected to worsen soon. Therefore, effective river management is essential to mitigate emissions and restore river ecosystems. The present study examined the relationship between water quality and CO₂ emission of rivers in the Uttarakhand state of India. The partial pressure of CO₂ (pCO₂) showed obvious spatial variation ranging from ~235 to 12,000 µatm with a mean value of 1860 µatm. Besides, pH, Biochemical Oxygen Demand (BOD), and Alkalinity emerged as significant predictors of pCO₂ (R²=0.95). Moreover, pCO₂ also had a strong positive correlation with BOD, Chemical Oxygen Demand (COD), phosphate, and nitrate. This study reveals the significant influence of pH, BOD, and Alkalinity on pCO₂ levels, underscoring the complex relationship between water quality and carbon dynamics in studied rivers. The correlation also emphasizes the impact of anthropogenic influences on CO₂ emissions in major rivers of Uttarakhand, providing valuable insights into the complex nature of carbon dynamics in studied rivers. The strong correlation between water parameters and anthropogenic activities highlights the need for targeted riverine ecosystem management and restoration interventions.