气候变化领域集成服务门户(CCPortal): Linking diatom-diazotroph symbioses to nitrogen cycle perturbations and deep-water anoxia: Insights from Mediterranean sapropel events

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DOI	10.1016/j.epsl.2021.117110
	Linking diatom-diazotroph symbioses to nitrogen cycle perturbations and deep-water anoxia: Insights from Mediterranean sapropel events
	Elling F.J.; Hemingway J.D.; Kharbush J.J.; Becker K.W.; Polik C.A.; Pearson A.
发表日期	2021
ISSN	0012821X
卷号	571
英文摘要	Elevated organic matter (OM) export flux promotes marine anoxia, thus increasing carbon sequestration efficiency and decreasing atmospheric carbon dioxide levels. However, the mechanisms that trigger and sustain anoxic events—particularly those associated with nutrient-poor, oligotrophic surface waters—remain poorly constrained. Mediterranean Sea sapropels are well-preserved sediments deposited during episodic anoxic events throughout the Plio-Pleistocene; as such, they may provide unique insight into the biogeochemical and ecological drivers of—and responses to—marine anoxia. Using biomarker distributions, we demonstrate that anaerobic ammonium oxidizing (anammox) bacteria and diazotrophic endosymbionts of mat- and/or raft-forming diatoms were both abundant during sapropel events, particularly in the Ionian and Libyan seas. In these sapropels, the carbon isotope compositions of anammox biomarkers directly capture progressive 13C-depletion in deep-water dissolved inorganic carbon, indicating sustained carbon sequestration. To explain these observations, we propose a reinforcing feedback whereby initial nutrient and/or circulation perturbations promote fixed nitrogen loss via intensified anammox and heterotrophic denitrification, which in turn favors proliferation of rapidly sinking diatom-diazotroph symbiotic consortia, increases OM burial flux, and sustains anoxia. This mechanism resolves the long-standing conundrum that small and buoyant diazotrophs are apparently associated with high OM export during periods of marine anoxia and oligotrophy. © 2021 The Author(s)
关键词	anammox anoxia compound-specific δ13C diatom-diazotroph symbioses Mediterranean sapropels N2-fixation
英文关键词	Atmospheric chemistry; Biogeochemistry; Carbon dioxide; Nitrogen; Nitrogen oxides; Nitrogen removal; Nutrients; Wastewater treatment; Anaerobics; Anerobic ammonium oxidizing; Anoxium; Compound-specific δ13C; Deepwater; Diatom-diazotroph symbiosis; Diazotroph; Mediterranean sapropel; N2-fixation; Organic matter exports; Biomarkers; Bacillariophyta
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203079
作者单位	Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, United States; Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02143, United States
推荐引用方式 GB/T 7714	Elling F.J.,Hemingway J.D.,Kharbush J.J.,et al. Linking diatom-diazotroph symbioses to nitrogen cycle perturbations and deep-water anoxia: Insights from Mediterranean sapropel events[J],2021,571.
APA	Elling F.J.,Hemingway J.D.,Kharbush J.J.,Becker K.W.,Polik C.A.,&Pearson A..(2021).Linking diatom-diazotroph symbioses to nitrogen cycle perturbations and deep-water anoxia: Insights from Mediterranean sapropel events.Earth and Planetary Science Letters,571.
MLA	Elling F.J.,et al."Linking diatom-diazotroph symbioses to nitrogen cycle perturbations and deep-water anoxia: Insights from Mediterranean sapropel events".Earth and Planetary Science Letters 571(2021).