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DOI	10.1073/pnas.1916109117
	A carbonate-rich lake solution to the phosphate problem of the origin of life
	Toner J.D.; Catling D.C.
发表日期	2020
ISSN	0027-8424
起始页码	883
结束页码	888
卷号	117 期号:2
英文摘要	Phosphate is central to the origin of life because it is a key component of nucleotides in genetic molecules, phospholipid cell membranes, and energy transfer molecules such as adenosine triphosphate. To incorporate phosphate into biomolecules, prebiotic experiments commonly use molar phosphate concentrations to overcome phosphate’s poor reactivity with organics in water. However, phosphate is generally limited to micromolar levels in the environment because it precipitates with calcium as low-solubility apatite minerals. This disparity between laboratory conditions and environmental constraints is an enigma known as “the phosphate problem.” Here we show that carbonate-rich lakes are a marked exception to phosphate-poor natural waters. In principle, modern carbonate-rich lakes could accumulate up to ∼0.1 molal phosphate under steady-state conditions of evaporation and stream inflow because calcium is sequestered into carbonate minerals. This prevents the loss of dissolved phosphate to apatite precipitation. Even higher phosphate concentrations (>1 molal) can form during evaporation in the absence of inflows. On the prebiotic Earth, carbonate-rich lakes were likely abundant and phosphate-rich relative to the present day because of the lack of microbial phosphate sinks and enhanced chemical weathering of phosphate minerals under relatively CO2-rich atmospheres. Furthermore, the prevailing CO2 conditions would have buffered phosphate-rich brines to moderate pH (pH 6.5 to 9). The accumulation of phosphate and other prebiotic reagents at concentration and pH levels relevant to experimental prebiotic syntheses of key biomolecules is a compelling reason to consider carbonate-rich lakes as plausible settings for the origin of life. © 2020 National Academy of Sciences. All rights reserved.
英文关键词	Carbonate-rich lakes; Early Earth; Origin of life; Phosphate
语种	英语
scopus关键词	apatite; calcium; carbon dioxide; carbonic acid; phosphate; prebiotic agent; water; Article; astronomy; atmosphere; concentration (parameter); environment; evaporation; geochemistry; lake; pH; precipitation; priority journal; stream (river); water flow; weathering
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/161093
作者单位	Toner, J.D., Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, United States; Catling, D.C., Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, United States
推荐引用方式 GB/T 7714	Toner J.D.,Catling D.C.. A carbonate-rich lake solution to the phosphate problem of the origin of life[J],2020,117(2).
APA	Toner J.D.,&Catling D.C..(2020).A carbonate-rich lake solution to the phosphate problem of the origin of life.Proceedings of the National Academy of Sciences of the United States of America,117(2).
MLA	Toner J.D.,et al."A carbonate-rich lake solution to the phosphate problem of the origin of life".Proceedings of the National Academy of Sciences of the United States of America 117.2(2020).