气候变化领域集成服务门户(CCPortal): Carotenoid biomarkers in Namibian shelf sediments: Anoxygenic photosynthesis during sulfide eruptions in the Benguela Upwelling System

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DOI	10.1073/pnas.2106040118
	Carotenoid biomarkers in Namibian shelf sediments: Anoxygenic photosynthesis during sulfide eruptions in the Benguela Upwelling System
	Ma J.; French K.L.; Cui X.; Bryant D.A.; Summons R.E.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:29
英文摘要	Aromatic carotenoid-derived hydrocarbon biomarkers are ubiquitous in ancient sediments and oils and are typically attributed to anoxygenic phototrophic green sulfur bacteria (GSB) and purple sulfur bacteria (PSB). These biomarkers serve as proxies for the environmental growth requirements of PSB and GSB, namely euxinic waters extending into the photic zone. Until now, prevailing models for environments supporting anoxygenic phototrophs include microbial mats, restricted basins and fjords with deep chemoclines, and meromictic lakes with shallow chemoclines. However, carotenoids have been reported in ancient open marine settings for which there currently are no known modern analogs that host GSB and PSB. The Benguela Upwelling System offshore Namibia, known for exceptionally high primary productivity, is prone to recurrent toxic gas eruptions whereupon hydrogen sulfide emanates from sediments into the overlying water column. These events, visible in satellite imagery as water masses clouded with elemental sulfur, suggest that the Benguela Upwelling System may be capable of supporting GSB and PSB. Here, we compare distributions of biomarkers in the free and sulfur-bound organic matter of Namibian shelf sediments. Numerous compounds—including acyclic isoprenoids, steranes, triterpanes, and carotenoids—were released from the polar lipid fractions upon Raney nickel desulfurization. The prevalence of isorenieratane and β-isorenieratane in sampling stations along the shelf verified anoxygenic photosynthesis by low-light-adapted, brown-colored GSB in this open marine setting. Renierapurpurane was also present in the sulfur-bound carotenoids and was typically accompanied by lower abundances of renieratane and β-renierapurpurane, thereby identifying cyanobacteria as an additional aromatic carotenoid source. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Biomarkers \| carotenoids \| sulfide \| Benguela Upwelling System \| anoxygenic photosynthesis
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/238472
作者单位	Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, MA, Cambridge, 02139, United Kingdom; School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200030, China; US Geological Survey, Central Energy Resources Science Center, CO, Denver, 80225, United States; Department of Biochemistry and Molecular Biology, Pennsylvania State University, PA, University Park, 16802, United States
推荐引用方式 GB/T 7714	Ma J.,French K.L.,Cui X.,et al. Carotenoid biomarkers in Namibian shelf sediments: Anoxygenic photosynthesis during sulfide eruptions in the Benguela Upwelling System[J],2021,118(29).
APA	Ma J.,French K.L.,Cui X.,Bryant D.A.,&Summons R.E..(2021).Carotenoid biomarkers in Namibian shelf sediments: Anoxygenic photosynthesis during sulfide eruptions in the Benguela Upwelling System.Proceedings of the National Academy of Sciences of the United States of America,118(29).
MLA	Ma J.,et al."Carotenoid biomarkers in Namibian shelf sediments: Anoxygenic photosynthesis during sulfide eruptions in the Benguela Upwelling System".Proceedings of the National Academy of Sciences of the United States of America 118.29(2021).