TY - JOUR
T1 - Is the River a Chemostat?
T2 - Scale Versus Land Use Controls on Nitrate Concentration-Discharge Dynamics in the Upper Mississippi River Basin
AU - Marinos, Richard E.
AU - Van Meter, Kimberly J.
AU - Basu, Nandita B.
N1 - Funding Information:
We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) [STPGP 494652–2016]. Data are available via Hydroshare ( https://doi.org/10.4211/hs.d5676355cbd94b79a2e58f8089040a40 ).
Publisher Copyright:
©2020. American Geophysical Union. All Rights Reserved.
PY - 2020/8/28
Y1 - 2020/8/28
N2 - The Upper Mississippi River Basin is the largest source of reactive nitrogen (N) to the Gulf of Mexico. Concentration-discharge (C-Q) relationships offer a means to understand both the terrestrial sources that generate this reactive N and the in-stream processes that transform it. Progress has been made on identifying land use controls on C-Q dynamics. However, the impact of basin size and river network structure on C-Q relationships is not well characterized. Here, we show, using high-resolution nitrate concentration data, that tile drainage is a dominant control on C-Q dynamics, with increasing drainage density contributing to more chemostatic C-Q behavior. We further find that concentration variability increases, relative to discharge variability, with increasing basin size across six orders of magnitude, and this pattern is attributed to different spatial correlation structures for C and Q. Our results show how land use and river network structure jointly control riverine N export.
AB - The Upper Mississippi River Basin is the largest source of reactive nitrogen (N) to the Gulf of Mexico. Concentration-discharge (C-Q) relationships offer a means to understand both the terrestrial sources that generate this reactive N and the in-stream processes that transform it. Progress has been made on identifying land use controls on C-Q dynamics. However, the impact of basin size and river network structure on C-Q relationships is not well characterized. Here, we show, using high-resolution nitrate concentration data, that tile drainage is a dominant control on C-Q dynamics, with increasing drainage density contributing to more chemostatic C-Q behavior. We further find that concentration variability increases, relative to discharge variability, with increasing basin size across six orders of magnitude, and this pattern is attributed to different spatial correlation structures for C and Q. Our results show how land use and river network structure jointly control riverine N export.
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U2 - 10.1029/2020GL087051
DO - 10.1029/2020GL087051
M3 - Article
AN - SCOPUS:85089896819
VL - 47
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 16
M1 - e2020GL087051
ER -