DOI: 10.1016/j.epsl.2021.117110
论文题名: Linking diatom-diazotroph symbioses to nitrogen cycle perturbations and deep-water anoxia: Insights from Mediterranean sapropel events
作者: Elling F.J. ; Hemingway J.D. ; Kharbush J.J. ; Becker K.W. ; Polik C.A. ; Pearson A.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 571 语种: 英语
中文关键词: 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
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) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165457
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
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]. Earth and Planetary Science Letters,2021-01-01,571