Journal article
Effects of storm size and frequency on nitrogen retention, denitrification, and N2O production in bioretention swale mesocosms
Biogeochemistry, Vol.134(3), pp.353-370
08/01/2017
Handle:
https://hdl.handle.net/2376/124064
Abstract
Reported nitrogen (N) retention efficiencies for bioretention swales vary widely, but reasons for this are not well-understood, in part because almost no studies have measured (or characterized controls on) bioretention swale denitrification. Here, we apply a novel N-2:Ar-based approach, in coordination with more established approaches, to estimate denitrification rates and compare bioretention N dynamics during artificial storms of two sizes (3.05 and 5.08 cm days(-1)) and following 4 inter-storm periods (initial storm with no prior storm, 1-, 7-, and 13-days). Denitrification rates during storms occurring after 7-days (520 +/- 150 mu mol N m(-2) h(-1)) were significantly higher than those during an initialization storm (13 +/- 34 mu mol N m(-2) h(-1)) or during a storm occurring one day after a previous storm (-63 +/- 65 mu mol N m(-2) h(-1)). No significant differences in N processing were observed between 3.05 and 5.08 cm days(-1) storms. Somewhat surprisingly, in all experiments [O-2] remained near saturated, and N2O emissions were very low or undetectable. Mesocosms were largely a net sink for dissolved inorganic N (DIN) and a net source of dissolved organic N (DON). Denitrification was neither a dominant nor consistent pathway for N removal, accounting for a maximum of 23 +/- 11% of DIN removal. Future research should continue to evaluate N assimilation as a N removal pathway in bioretention swales, as well as characterize N dynamics during unsaturated conditions associated with smaller rain events and during periods between the large storms examined here.
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Details
- Title
- Effects of storm size and frequency on nitrogen retention, denitrification, and N2O production in bioretention swale mesocosms
- Creators
- Richard A Norton - Washington State UniversityJohn A Harrison - Washington State University VancouverC. Kent Keller - Washington State UniversityKevan B Moffett - Washington State University
- Publication Details
- Biogeochemistry, Vol.134(3), pp.353-370
- Academic Unit
- Environment, School of the (CAS); Harrison Research Group: Global Change and Watershed Biochemistry
- Publisher
- SPRINGER
- Number of pages
- 18
- Grant note
- National Science Foundation ULTRA-Ex Portland Vancouver Rotary Club USGS 104(b) / Washington Water Research Center grant Robert Lane Fellowship Washington State University Vancouver
- Identifiers
- 99900667908701842
- Language
- English
- Resource Type
- Journal article