Journal article
Nitrate uptake in an agricultural stream estimated from high-frequency, in-situ sensors
Environmental monitoring and assessment, Vol.190(4), pp.226-16
04/01/2018
DOI: 10.1007/s10661-018-6599-1
PMID: 29550885
Abstract
Real-time, continuous, in situ water quality sensors were deployed on a fourth-order Iowa (U.S.) stream draining an agricultural watershed to evaluate key in-stream processes affecting concentrations of nitrate during a 24-day late summer (Aug-Sep) period. Overall, nitrate-nitrogen (NO3-N) concentrations declined 0.11 mg L-1 km(-1), or about 1.9% km(-1) and 35% in total across 18 km. We also calculated stream metabolic rates using in situ dissolved oxygen data and determined stream biotic N demand to be 108117 mg m(-2) day(-1). From this, we estimate that 11% of the NO3-N concentration decline measured between two in-situ sensors separated by 2 km was a result of biotic NO3-N demand, while groundwater NO3-N data and estimates of groundwater flow contributions indicate that dilution was responsible for 53%. Because the concentration decline extends linearly across the entire 18 km of stream length, these processes seem consistent throughout the basin downstream of the most upstream sensor site. The nitrate-dissolved oxygen relationship between the two sites separated by 2 km, calculations of biotic NO3-N demand, and diurnal variations in NO3-N concentration all indicate that denitrification by an-aerobes is removing less NO3-N than that assimilated by aquatic organisms unable to fix nitrogen for their life processes, and thus the large majority of the NO3-N entering this stream is not retained or removed, but rather transported downstream.
Details
- Title: Subtitle
- Nitrate uptake in an agricultural stream estimated from high-frequency, in-situ sensors
- Creators
- Christopher S. Jones - Univ Iowa, IIHR Hydrosci & Engn, 306 C Maxwell Stanley Hydraul Lab, Iowa City, IA 52242 USASea-won Kim - University of IowaThomas F. Wilton - Iowa Department of Natural ResourcesKeith E. Schilling - United States Geological SurveyCaroline A. Davis - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Environmental monitoring and assessment, Vol.190(4), pp.226-16
- Publisher
- Springer Nature
- DOI
- 10.1007/s10661-018-6599-1
- PMID
- 29550885
- ISSN
- 0167-6369
- eISSN
- 1573-2959
- Number of pages
- 16
- Language
- English
- Date published
- 04/01/2018
- Academic Unit
- Earth and Environmental Sciences; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984383907402771
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