Constraining the role of iron in environmental nitrogen transformations. Dual stable isotope systematics of abiotic NO<sub>2</sub>- reduction by Fe(II) and its production of N<sub>2</sub>O

doi:10.2172/1214871

GSTDTAP > 地球科学

DOI	10.2172/1214871
报告编号	SC0006681
来源ID	OSTI ID: 1214871
	Constraining the role of iron in environmental nitrogen transformations. Dual stable isotope systematics of abiotic NO₂- reduction by Fe(II) and its production of N₂O
	Johnston, David; Wankel, Scott David; Buchwald, Carolyn; Hansel, Colleen
	2015-09-16
出版年	2015
页数	43
语种	英语
国家	美国
领域	地球科学
英文摘要	Redox reactions involving nitrogen and iron have been shown to have important implications for mobilization of priority contaminants. Thus, an understanding of the linkages between their biogeochemical cycling is critical for predicting subsurface mobilization of radionuclides such as uranium. Despite mounting evidence for biogeochemical interactions between iron and nitrogen, our understanding of their environmental importance remains limited. Here we present an investigation of abiotic nitrite (NO₂^-) reduction by Fe(II) or âchemodenitrification,â and its relevance to the production of nitrous oxide (N₂O), specifically focusing on dual (N and O) isotope systematics under a variety of environmentally relevant conditions. We observe a range of kinetic isotope effects that are regulated by reaction rates, with faster rates at higher pH (~8), higher concentrations of Fe(II) and in the presence of mineral surfaces. A clear non-linear relationship between rate constant and kinetic isotope effects of NO₂^- reduction was evident (with larger isotope effects at slower rates) and is interpreted as reflecting the dynamics of Fe(II)-N reaction intermediates. N and O isotopic composition of product N₂O also suggests a complex network of parallel and/or competing pathways. Our findings suggest that NO₂^- reduction by Fe(II) may represent an important abiotic source of environmental N₂O, especially in iron-rich environments experiencing dynamic redox variations. This study provides a multi-compound, multi-isotope framework for evaluating the environmental occurrence of abiotic NO₂^- reduction and N₂O formation, helping future studies constrain the relative roles of abiotic and biological N₂O production pathways.
英文关键词	nitrogen iron redox stable isotope nitrous oxide nitrite
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来源平台	US Department of Energy (DOE)
引用统计
文献类型	科技报告
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/6842
专题	地球科学
推荐引用方式 GB/T 7714	Johnston, David,Wankel, Scott David,Buchwald, Carolyn,et al. Constraining the role of iron in environmental nitrogen transformations. Dual stable isotope systematics of abiotic NO₂- reduction by Fe(II) and its production of N₂O,2015.