气候变化领域集成服务门户(CCPortal): Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean

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DOI	10.1073/pnas.1721733115
	Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean
	Zheng W.; Gilleaudeau G.J.; Kah L.C.; Anbar A.D.
发表日期	2018
ISSN	0027-8424
起始页码	10594
结束页码	10599
卷号	115 期号:42
英文摘要	Photic zone euxinia (PZE) is a condition where anoxic, H2S-rich waters occur in the photic zone (PZ). PZE has been invoked as an impediment to the evolution of complex life on early Earth and as a kill mechanism for Phanerozoic mass extinctions. Here, we investigate the potential application of mercury (Hg) stable isotopes in marine sedimentary rocks as a proxy for PZE by measuring Hg isotope compositions in late Mesoproterozoic (∼1.1 Ga) shales that have independent evidence of PZE during discrete intervals. Strikingly, a significantly negative shift of Hg mass-independent isotope fractionation (MIF) was observed during euxinic intervals, suggesting changes in Hg sources or transformations in oceans coincident with the development of PZE. We propose that the negative shift of Hg MIF was most likely caused by (i) photoreduction of Hg(II) complexed by reduced sulfur ligands in a sulfide-rich PZ, and (ii) enhanced sequestration of atmospheric Hg(0) to the sediments by thiols and sulfide that were enriched in the surface ocean as a result of PZE. This study thus demonstrates that Hg isotope compositions in ancient marine sedimentary rocks can be a promising proxy for PZE and therefore may provide valuable insights into changes in ocean chemistry and its impact on the evolution of life. © 2018 National Academy of Sciences. All rights reserved.
英文关键词	Mass-independent fractionation; Mercury; Mesoproterozoic; Photic zone euxinia; Stable isotopes
语种	英语
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/160457
作者单位	Zheng, W., School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, United States; Gilleaudeau, G.J., School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, United States, Department of Atmospheric, Oceanic, and Earth Sciences, George Mason University, Fairfax, VA 22030, United States; Kah, L.C., Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996, United States; Anbar, A.D., School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, United States, School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, United States
推荐引用方式 GB/T 7714	Zheng W.,Gilleaudeau G.J.,Kah L.C.,et al. Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean[J],2018,115(42).
APA	Zheng W.,Gilleaudeau G.J.,Kah L.C.,&Anbar A.D..(2018).Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean.Proceedings of the National Academy of Sciences of the United States of America,115(42).
MLA	Zheng W.,et al."Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean".Proceedings of the National Academy of Sciences of the United States of America 115.42(2018).