The authors regret that, during analyses of various data sets, we inadvertently used TKN (Total Kjeldahl Nitrogen) in place of TN (Total Nitrogen) for the Maumee River tributary. We now present the corrected data from the original Fig. 5 (as Fig. 5 (corrected) in this article) which demonstrates that our initial conclusions discussed within the paragraph where Fig. 5 is referenced in the paper were exaggerated. To generate this information, TKN from the data set cited in the original text (which includes organic forms of N as well as ammonia) was augmented with NO3 + NO2 estimates from the same data set to generate a revised TN estimate.