"Nutrient load characterization from integrated source data for the Lower Mississippi River," by J. E. Bollinger, L. J. Steinberg, A. J. Englande, J.P. Crews, J. M. Hughes, C. Velasco, K. H. Watanabe, W. R. Hartley, C. M. Swalm, J. M. Mendler, L. E. White, and W. J. George - Discussion