High Concentration of Sulphate Coupled with Climate Warming Generates Ecosystem Feedback Under Sub-Oxic Conditions at Sediment-Water Interface in the Ganga River.

Here, we quantified sediment phosphorus (P) release in relation to concentrations of dissolved oxygen (DO) and sulphate, and increase in temperature in a major river of India subjected to long-term human perturbations. We found a substantial increase in sediment P release, an ecosystem feedback, at higher concentrations of sulphate, more towards the lower end of DO concentrations. A 2°C warming increased sediment P release upto 25.21% and caused a drop in DO level by 16%. Our findings reconcile the observed sulphate-driven changes in sediment P release across systems, and provide first experimental evidence of warming-induced increases. Our results imply that aquatic ecosystems will undergo self-fertilizing effect as the planet warming interacts with other human perturbations. This has implications for eutrophication linkages and ecosystem functioning.