Record Details
Coupling multiscale observations to evaluate hyporheic nitrate removal at the reach scale
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Coupling multiscale observations to evaluate hyporheic nitrate removal at the reach scale |
| Names |
Zarnetske, Jay P.
(creator) Haggerty, Roy (creator) Wondzell, Steven M. (creator) |
| Date Issued | 2015-03 (iso8601) |
| Note | To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The article is copyrighted by the Society for Freshwater Science and published by the University of Chicago Press. It can be found at: http://www.jstor.org/action/showPublication?journalCode=fresscie. |
| Abstract | Excess NO₃⁻ in streams is a growing and persistent problem for both inland and coastal ecosystems, and denitrification is the primary removal process for NO₃⁻. Hyporheic zones can have high denitrification potentials, but their role in reach- and network-scale NO₃⁻ removal is unknown because it is difficult to estimate. We used independent and complementary multiscale measurements of denitrification and total NO₃⁻ uptake to quantify the role of hyporheic NO₃⁻ removal in a 303-m reach of a 3rd-order agricultural stream in western Oregon, USA. We characterized the reach-scale NO₃⁻ dynamics with steady-state ¹⁵N-NO₃⁻ tracer-addition experiments and solute-transport modeling, and measured the hyporheic conditions via in-situ biogeochemical and groundwater modeling. We also developed a method to link these independent multiscale measurements. Hyporheic NO₃⁻ removal (rate coefficient λ[subscript HZ] = 0.007/h) accounted for 17% of the observed total reach NO₃⁻ uptake and 32% of the reach denitrification estimated from the ¹⁵N experiments. The primary limitations on hyporheic denitrification at the reach scale were availability of labile dissolved organic C and the restricted size of the hyporheic zone caused by anthropogenic channelization (sediment thickness ≤ 1.5 m). Linking multiscale methods made estimates possible for hyporheic influence on stream NO₃⁻ dynamics. However, it also demonstrated that the traditional reach-scale tracer experimental designs and subsequent transport modeling cannot be used alone to directly investigate the role of the hyporheic zone on reach-scale water and solute dynamics. |
| Genre | Article |
| Topic | surface-water–groundwater interaction |
| Identifier | Zarnetske, J. P., Haggerty, R., & Wondzell, S. M. (2015). Coupling multiscale observations to evaluate hyporheic nitrate removal at the reach scale. Freshwater Science, 34(1), 172-186. doi:10.1086/680011 |
