气候变化领域集成服务门户(CCPortal): Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery

CCPortal

DOI	10.1088/1748-9326/ab751b
	Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery
	Schmadel N.M.; Harvey J.W.; Alexander R.B.; Boyer E.W.; Schwarz G.E.; Gomez-Velez J.D.; Scott D.; Konrad C.P.
发表日期	2020
ISSN	17489318
卷号	15 期号:4
英文摘要	River corridors store, convey, and process nutrients from terrestrial and upstream sources, regulating delivery from headwaters to estuaries. A consequence of chronic excess nitrogen loading, as supported by theory and field studies in specific watersheds, is saturation of the biogeochemically-mediated nitrogen removal processes that weakens the capacity of the river corridor to remove nitrogen. Regional nitrogen models typically assume that removal capacity exhibits first-order behavior, scaling positively and linearly with increasing concentration, which may bias the estimation of where and at what rate nitrogen is removed by river corridors. Here we estimate the nitrogen concentration saturation threshold and its effects on annual nitrogen export from the Northeastern United States, revealing an average 42% concentration-induced reduction in headwater removal capacity. The weakened capacity caused an average 10% increase in the predicted delivery of riverine nitrogen from urban and agricultural watersheds compared to estimates using first-order process assumptions. Our results suggest that nitrogen removal may fall below a first-order rate process as riverine concentration increases above a threshold of 0.5 mg N l-1. Threshold behavior indicates that even modest mitigation of nitrogen concentration in river corridors above the threshold can cause a self-reinforcing boost to nitrogen removal. © 2020 The Author(s). Published by IOP Publishing Ltd.
英文关键词	Headwaters; Nitrogen concentration saturation; Regional nitrogen budget; River corridor
语种	英语
scopus关键词	Agricultural robots; Rivers; Watersheds; Agricultural watersheds; First-order process; First-order rates; Nitrogen concentrations; Nitrogen removal process; Riverine nitrogens; Self reinforcing; Threshold behavior; Nitrogen removal; agricultural emission; biogeochemistry; coastal zone; concentration (composition); headwater; nitrogen; nutrient enrichment; pollutant removal; saturation; United States
来源期刊	Environmental Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154074
作者单位	Us Geological Survey, Earth System Processes Division, Reston, VA, United States; Us Geological Survey, Integrated Modeling and Prediction Division, Reston, VA, United States; Department of Ecosystem Science and Management, Penn State, State College, PA, United States; Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, United States; Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA, United States; Us Geological Survey, Washington Water Science Center, Tacoma, WA, United States
推荐引用方式 GB/T 7714	Schmadel N.M.,Harvey J.W.,Alexander R.B.,et al. Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery[J],2020,15(4).
APA	Schmadel N.M..,Harvey J.W..,Alexander R.B..,Boyer E.W..,Schwarz G.E..,...&Konrad C.P..(2020).Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery.Environmental Research Letters,15(4).
MLA	Schmadel N.M.,et al."Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery".Environmental Research Letters 15.4(2020).