气候变化领域集成服务门户(CCPortal): Upper Midwest lakes are supersaturated with N2

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DOI	10.1073/pnas.1921689117
	Upper Midwest lakes are supersaturated with N2
	Loeks-Johnson B.M.; Cotner J.B.
发表日期	2020
ISSN	0027-8424
起始页码	17063
结束页码	17067
卷号	117 期号:29
英文摘要	Little is known about the exchange of gaseous nitrogen (N2) with the atmosphere in freshwater systems. Although the exchange of N2, driven by excess or deficiencies relative to saturation values, has little relevance to the atmospheric N2 pool due to its large size, it does play an important role in freshwater and marine nitrogen (N) cycling. N-fixation converts N2 to ammonia, which can be used by microbes and phytoplankton, while denitrification/anammox effectively removes it by converting oxidized, inorganic N to N2. We examined N2 saturation to infer net biological nitrogen processes in 34 lakes across 5° latitude varying in trophic status, mixing regime, and bathymetry. Here, we report that nearly all lakes examined in the upper Midwest (USA) were supersaturated with N2 (>85% of samples, n = 248), suggesting lakes are continuously releasing nitrogen to the atmosphere. The traditional paradigm is that freshwaters compensate for N-limitation through N-fixation, but these results indicate that lakes were constantly losing N to the atmosphere via denitrification and/or anammox, suggesting that terrestrial N inputs are needed to balance the internal N cycle. © 2020 National Academy of Sciences. All rights reserved.
英文关键词	Biogeochemistry; Denitrification; Nitrogen cycling; Nitrogen fixation
语种	英语
scopus关键词	nitrogen; argon; nitrogen; oxygen; anaerobic ammonium oxidation; Article; biogeochemistry; controlled study; denitrification; nitrogen cycle; nitrogen fixation; priority journal; seasonal variation; trophic level; chemistry; greenhouse gas; lake; Minnesota; Argon; Greenhouse Gases; Lakes; Minnesota; Nitrogen; Nitrogen Fixation; Oxygen
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160883
作者单位	Loeks-Johnson, B.M., Department of Ecology Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, United States; Cotner, J.B., Department of Ecology Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, United States
推荐引用方式 GB/T 7714	Loeks-Johnson B.M.,Cotner J.B.. Upper Midwest lakes are supersaturated with N2[J],2020,117(29).
APA	Loeks-Johnson B.M.,&Cotner J.B..(2020).Upper Midwest lakes are supersaturated with N2.Proceedings of the National Academy of Sciences of the United States of America,117(29).
MLA	Loeks-Johnson B.M.,et al."Upper Midwest lakes are supersaturated with N2".Proceedings of the National Academy of Sciences of the United States of America 117.29(2020).