气候变化领域集成服务门户(CCPortal): Physical mixing in coastal waters controls and decouples nitrification via biomass dilution

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DOI	10.1073/pnas.2004877118
	Physical mixing in coastal waters controls and decouples nitrification via biomass dilution
	Haas S.; Robicheau B.M.; Rakshit S.; Tolman J.; Algar C.K.; LaRoche J.; Wallace D.W.R.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:18
英文摘要	Nitrification is a central process of the aquatic nitrogen cycle that controls the supply of nitrate used in other key processes, such as phytoplankton growth and denitrification. Through time series observation and modeling of a seasonally stratified, eutrophic coastal basin, we demonstrate that physical dilution of nitrifying microorganisms by water column mixing can delay and decouple nitrification. The findings are based on a 4-y, weekly time series in the subsurface water of Bedford Basin, Nova Scotia, Canada, that included measurement of functional (amoA) and phylogenetic (16S rRNA) marker genes. In years with colder winters, more intense winter mixing resulted in strong dilution of resident nitrifiers in subsurface water, delaying nitrification for weeks to months despite availability of ammonium and oxygen. Delayed regrowth of nitrifiers also led to transient accumulation of nitrite (3 to 8 μmol · kgsw−1) due to decoupling of ammonia and nitrite oxidation. Nitrite accumulation was enhanced by ammonia-oxidizing bacteria (Nitrosomonadaceae) with fast enzyme kinetics, which temporarily outcompeted the ammonia-oxidizing archaea (Nitrosopumilus) that dominated under more stable conditions. The study reveals how physical mixing can drive seasonal and interannual variations in nitrification through control of microbial biomass and diversity. Variable, mixing-induced effects on functionally specialized microbial communities are likely relevant to biogeochemical transformation rates in other seasonally stratified water columns. The detailed study reveals a complex mechanism through which weather and climate variability impacts nitrogen speciation, with implications for coastal ecosystem productivity. It also emphasizes the value of high-frequency, multiparameter time series for identifying complex controls of biogeochemical processes in aquatic systems. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Aquatic nitrogen biogeochemistry; Nitrifier diversity; Nitrite accumulation; Thaumarchaeota; Time series
语种	英语
scopus关键词	ammonia; nitrite; oxygen; RNA 16S; ammonia oxidizing archaeon; Article; bioaccumulation; biomass; climate change; coastal waters; dilution; environmental aspects and related phenomena; enzyme kinetics; microbial community; nitrification; Nitrosomonadaceae; Nitrosopumilus; oxidation; phylogeny; physical mixing; priority journal; seasonal variation; species differentiation; species diversity
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/238585
作者单位	Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
推荐引用方式 GB/T 7714	Haas S.,Robicheau B.M.,Rakshit S.,et al. Physical mixing in coastal waters controls and decouples nitrification via biomass dilution[J],2021,118(18).
APA	Haas S..,Robicheau B.M..,Rakshit S..,Tolman J..,Algar C.K..,...&Wallace D.W.R..(2021).Physical mixing in coastal waters controls and decouples nitrification via biomass dilution.Proceedings of the National Academy of Sciences of the United States of America,118(18).
MLA	Haas S.,et al."Physical mixing in coastal waters controls and decouples nitrification via biomass dilution".Proceedings of the National Academy of Sciences of the United States of America 118.18(2021).