Abstract
We used stream chemistry and hydrogeomorphology data from 549 stream and 447 river sites to estimate NO3-N removal in the Upper Mississippi, Missouri, and Ohio Rivers. We used two N removal models to predict NO3-N input and removal. NO3-N input ranged from 0.01 to 338 kg km-1d-1 in the Upper Mississippi River to <0.01-54 kg km-1d-1 in the Missouri River. Cumulative river network NO3-N input was 98700-101676 Mg year-1 in the Ohio River, 85961-89288 Mg year-1 in the Upper Mississippi River, and 59463-61541 Mg year-1 in the Missouri River. NO3-N output was highest in the Upper Mississippi River (0.01-329 kg km-1d-1), followed by the Ohio and Missouri Rivers (<0.01-236 kg km-1d-1) sub-basins. Cumulative river network NO3-N output was 97499 Mg year-1 for the Ohio River, 84361 Mg year-1 for the Upper Mississippi River, and 59200 Mg year-1 for the Missouri River. Proportional NO3-N removal (PNR) based on the two models ranged from <0.01 to 0.28. NO3-N removal was inversely correlated with stream order, and ranged from <0.01 to 8.57 kg km-1d-1 in the Upper Mississippi River to <0.001-1.43 kg km-1d-1 in the Missouri River. Cumulative river network NO3-N removal predicted by the two models was: Upper Mississippi River 4152 and 4152 Mg year-1, Ohio River 3743 and 378 Mg year-1, and Missouri River 2277 and 197 Mg year-1. PNR removal was negatively correlated with both stream order (r= -0.80-0.87) and the percent of the catchment in agriculture (r= -0.38-0.76).
Original language | English (US) |
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Pages (from-to) | 183-194 |
Number of pages | 12 |
Journal | Biogeochemistry |
Volume | 102 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 2011 |
Keywords
- Mississippi River basin
- Nitrogen removal
- River networks