气候变化领域集成服务门户(CCPortal): Global silicate weathering flux overestimated because of sediment-water cation exchange

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DOI	10.1073/pnas.2016430118
	Global silicate weathering flux overestimated because of sediment-water cation exchange
	Tipper E.T.; Stevenson E.I.; Alcock V.; Knight A.C.G.; Baronas J.J.; Hilton R.G.; Bickle M.J.; Larkin C.S.; Feng L.; Relph K.E.; Hughes G.
发表日期	2020
ISSN	0027-8424
卷号	118 期号:1
英文摘要	Rivers carry the dissolved and solid products of silicate mineral weathering, a process that removes CO2from the atmosphere and provides a key negative climate feedback over geological timescales. Here we show that, in some river systems, a reactive exchange pool on river suspended particulate matter, bonded weakly to mineral surfaces, increases the mobile cation flux by 50%. The chemistry of both river waters and the exchange pool demonstrates exchange equilibrium, confirmed by Sr isotopes. Global silicate weathering fluxes are calculated based on riverine dissolved sodium (Na+) from silicate minerals. The large exchange pool supplies Na+of nonsilicate origin to the dissolved load, especially in catchments with widespread marine sediments, or where rocks have equilibrated with saline basement fluids. We quantify this by comparing the riverine sediment exchange pool and river water chemistry. In some basins, cation exchange could account for the majority of sodium in the river water, significantly reducing estimates of silicate weathering. At a global scale, we demonstrate that silicate weathering fluxes are overestimated by 12 to 28%. This overestimation is greatest in regions of high erosion and high sediment loads where the negative climate feedback has a maximum sensitivity to chemical weathering reactions. In the context of other recent findings that reduce the net CO2consumption through chemical weathering, the magnitude of the continental silicate weathering fluxes and its implications for solid Earth CO2degassing fluxes need to be further investigated. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Cation exchange; Global biogeochemical cycles; Silicate weathering; Suspended particulate matter
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/161103
作者单位	Tipper, E.T., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Stevenson, E.I., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Alcock, V., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Knight, A.C.G., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Baronas, J.J., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Hilton, R.G., Department of Geography, Durham University, Durham, DH1 3LE, United Kingdom; Bickle, M.J., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Larkin, C.S., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Feng, L., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom; Relph, K.E., Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, U...
推荐引用方式 GB/T 7714	Tipper E.T.,Stevenson E.I.,Alcock V.,et al. Global silicate weathering flux overestimated because of sediment-water cation exchange[J],2020,118(1).
APA	Tipper E.T..,Stevenson E.I..,Alcock V..,Knight A.C.G..,Baronas J.J..,...&Hughes G..(2020).Global silicate weathering flux overestimated because of sediment-water cation exchange.Proceedings of the National Academy of Sciences of the United States of America,118(1).
MLA	Tipper E.T.,et al."Global silicate weathering flux overestimated because of sediment-water cation exchange".Proceedings of the National Academy of Sciences of the United States of America 118.1(2020).