气候变化领域集成服务门户(CCPortal): Ordovician cyanobacterial calcification: A marine fossil proxy for atmospheric CO2

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DOI	10.1016/j.epsl.2019.115950
	Ordovician cyanobacterial calcification: A marine fossil proxy for atmospheric CO2
	Liu L.; Liang L.; Wu Y.; Zhou X.; Jia L.; Riding R.
发表日期	2020
ISSN	0012821X
卷号	530
英文摘要	Ordovician atmospheric CO2 level was an important influence on climate and life. However, modelled estimates of Ordovician CO2 differ widely and, in contrast to much of the subsequent Phanerozoic, they lack fossil proxy constraints. In vivo cyanobacterial sheath calcification, promoted by carbon dioxide concentrating mechanisms (CCMs), creates distinctive microfossils. These provide a direct ecophysiological link to ambient concentrations of CO2 and, to a lesser extent, O2. Cyanobacteria do not calcify at high CO2 concentrations. Experiments show that CCMs can be induced in present-day cyanobacteria at CO2 levels below ∼10 times present atmospheric level (PAL) and that this promotes sheath calcification. We compiled a global database of cyanobacterial calcification in marine environments throughout the Ordovician (485-443 Myr ago) and compared it with modelled estimates of atmospheric CO2 and O2. These data show that many genera of marine calcified cyanobacteria reappeared from Cambrian Series 2 or first appeared globally during the late middle to late Upper Ordovician (late Darriwilian to late Katian) in carbonate platform facies, resulting in a previously unrecognized ten-fold increase in global diversity. Such a large increase in calcification suggests widespread induction of CCM expression in cyanobacteria, consistent with sustained decline in external CO2 concentrations below ∼10× PAL, together with increase in dissolved O2 level, during the late Darriwilian, Sandbian and Katian stages, ∼460-445 Myr ago. These cyanobacterial calcification fossil proxy data provide a first order constraint on modelled estimates of atmospheric CO2 for the Ordovician. Estimated CO2 outputs from COPSE and recent GEOCARB-based models are broadly consistent with this cyanobacterial calcification proxy for the Ordovician. In view of the long history of cyanobacteria, the calcified cyanobacterial proxy offers potential to assist interpretation of CO2 deeper into geological time. © 2019 Elsevier B.V.
关键词	calcification CO2 cyanobacteria modelling Ordovician photosynthesis
英文关键词	Biomineralization; Bone; Calcification (biochemistry); Models; Photosynthesis; Ambient concentrations; Atmospheric levels; Carbonate platforms; CO2 concentration; cyanobacteria; Influence on climate; Marine environment; Ordovician; Carbon dioxide; calcification; carbon dioxide; cyanobacterium; fossil; marine atmosphere; Ordovician; photosynthesis; proxy climate record; Cyanobacteria
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/202748
作者单位	State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environment, Department of Geology, Northwest University, Xi'an, 710069, China; Geoconsultants Corporation, Kevil, KY 42053, United States; Key Laboratory of Petroleum Resource Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996-1526, United States
推荐引用方式 GB/T 7714	Liu L.,Liang L.,Wu Y.,et al. Ordovician cyanobacterial calcification: A marine fossil proxy for atmospheric CO2[J],2020,530.
APA	Liu L.,Liang L.,Wu Y.,Zhou X.,Jia L.,&Riding R..(2020).Ordovician cyanobacterial calcification: A marine fossil proxy for atmospheric CO2.Earth and Planetary Science Letters,530.
MLA	Liu L.,et al."Ordovician cyanobacterial calcification: A marine fossil proxy for atmospheric CO2".Earth and Planetary Science Letters 530(2020).