A new paper in the Proceedings of the National Academies shows that nutrient-rich discharge greatly enhances the biological pump mechanism of carbon sequestration. The sequestration happens as the discharge plume enters deep water off the continental shelf, where excess iron, phosphorous, and silica stimulate diatoms and nitrogen-fixing diazotrophs. The measured carbon sequestration rates are very high in the area of the discharge plume.
Read the paper in PNAS (free download).
Read an article from the National Science Foundation.