气候变化领域集成服务门户(CCPortal): Synchronous rise of African C4 ecosystems 10 million years ago in the absence of aridification

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DOI	10.1038/s41561-019-0399-2
	Synchronous rise of African C4 ecosystems 10 million years ago in the absence of aridification
	Polissar P.J.; Rose C.; Uno K.T.; Phelps S.R.; deMenocal P.
发表日期	2019
ISSN	17520894
卷号	12 期号:8
英文摘要	Grasslands expanded globally during the late Cenozoic and the development of these ecosystems shaped the evolution of many faunal groups, including our hominin ancestors. The emergence of these ecosystems has been dated in many regions, but the origins of the iconic African C4 savannah grasslands remain poorly known, as do the causal factors that led to their establishment. Here we document their origins with the distinct carbon isotope signature from the hot-, arid- and low-CO2-adapted C4 grasses that dominate modern savannahs and grasslands. We use the carbon isotope values of leaf-wax molecules in deep-sea drill cores to measure the rise of African C4 ecosystems. We also reconstruct African palaeohydroclimate change from leaf-wax hydrogen isotope values and dust deposition rates in these cores. We find that C4-dominated ecosystems expanded synchronously across Northwestern and East Africa after 10 million years ago. This was not accompanied by substantial changes in palaeohydrology or dust deposition, precluding aridification as a causal factor. The expansion of C4 grasses was coincident, however, with dramatic high-latitude cooling and increased pole–Equator temperature gradients. We suggest that declining atmospheric CO2 levels were a direct cause of the C4 grassland expansion. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
语种	英语
scopus关键词	aridification; C4 plant; carbon isotope; Cenozoic; cooling; depositional environment; dust; grassland soil; hydrogen isotope; paleobotany; paleohydrology; savanna; wax; East Africa; Poaceae
来源期刊	Nature Geoscience
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/124623
作者单位	Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory, Palisades, NY, United States; Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States
推荐引用方式 GB/T 7714	Polissar P.J.,Rose C.,Uno K.T.,et al. Synchronous rise of African C4 ecosystems 10 million years ago in the absence of aridification[J],2019,12(8).
APA	Polissar P.J.,Rose C.,Uno K.T.,Phelps S.R.,&deMenocal P..(2019).Synchronous rise of African C4 ecosystems 10 million years ago in the absence of aridification.Nature Geoscience,12(8).
MLA	Polissar P.J.,et al."Synchronous rise of African C4 ecosystems 10 million years ago in the absence of aridification".Nature Geoscience 12.8(2019).