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DOI	10.1007/s10533-020-00674-7
	Experimental shifts of hydrologic residence time in a sandy urban stream sediment–water interface alter nitrate removal and nitrous oxide fluxes
	Hampton T.B.; Zarnetske J.P.; Briggs M.A.; MahmoodPoor Dehkordy F.; Singha K.; Day-Lewis F.D.; Harvey J.W.; Chowdhury S.R.; Lane J.W.
发表日期	2020
ISSN	0168-2563
起始页码	195
结束页码	219
卷号	149 期号:2
英文摘要	The sediment–water interfaces (SWI) of streams serve as important biogeochemical hotspots in watersheds and contribute to whole-catchment reactive nitrogen budgets and water-quality conditions. Recently, the SWI has been identified as an important source of nitrous oxide (N2O) produced in streams, with SWI residence time among the principal controls on its production. Here, we conducted a series of controlled manipulations of SWI exchange in an urban stream that has high dissolved N2O concentrations and where we concurrently evaluated less-mobile porosity dynamics. Our experiments took place within isolated portions of two sediment types: a coarse sandy stream bed resulting from excess road-sand application in the watershed, and a coarse sand mixed with clay and organic particles. In these manipulation experiments we systematically varied SWI vertical-flux rates and residence times to evaluate their effect on the fate of nitrate and production rates of N2O. Our experiments demonstrate that the fate and transport of nitrate and N2O production are influenced by hydrologic flux rates through SWI sediments and associated residence times. Specifically, we show that manipulations of hydrologic flux systematically shifted the depth of the bulk oxic–anoxic interface in the sediments, and that nitrate removal increased with residence time. Our results also support the emerging hypothesis of a ‘Goldilocks’ timescale for the production of nitrous oxide, when transport and reaction timescales favor incomplete denitrification. Areal N2O production rates were up to threefold higher during an intermediate residence-time experiment, compared to shorter or longer residence times. In our companion study we documented that the studied sediments were dominated by a long-residence-time less-mobile porosity domain, which could explain why we observed N2O production even in bulk-oxic sediments. Overall, we have experimentally demonstrated that changes to SWI hydrologic residence times and SWI substrate associated with urbanization can change the biogeochemical function of the river corridor. © 2020, Springer Nature Switzerland AG.
英文关键词	Denitrification; Nitrogen; Nitrous oxide; Nutrient cycling; Sediment–water interface; Urban biogeochemistry
语种	英语
scopus关键词	biogeochemistry; hydrogeochemistry; hydrological modeling; hypothesis testing; nitrous oxide; porosity; residence time; sediment-water interface; timescale
来源期刊	Biogeochemistry
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/153131
作者单位	Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, United States; Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada; Earth System Processes Division, Hydrogeophysics Branch, U.S. Geological Survey, Storrs, CT, United States; Department of Civil and Environmental Engineering, University of Connecticut, Storrs, CT, United States; Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States; Hydrologic Science and Engineering Program, Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO, United States; Earth Surface Processes Division, Water Cycle Branch, U.S. Geological Survey, Reston, VA, United States
推荐引用方式 GB/T 7714	Hampton T.B.,Zarnetske J.P.,Briggs M.A.,等. Experimental shifts of hydrologic residence time in a sandy urban stream sediment–water interface alter nitrate removal and nitrous oxide fluxes[J],2020,149(2).
APA	Hampton T.B..,Zarnetske J.P..,Briggs M.A..,MahmoodPoor Dehkordy F..,Singha K..,...&Lane J.W..(2020).Experimental shifts of hydrologic residence time in a sandy urban stream sediment–water interface alter nitrate removal and nitrous oxide fluxes.Biogeochemistry,149(2).
MLA	Hampton T.B.,et al."Experimental shifts of hydrologic residence time in a sandy urban stream sediment–water interface alter nitrate removal and nitrous oxide fluxes".Biogeochemistry 149.2(2020).