干旱区生态环境知识资源中心(Arid): Modelling the C-14 bomb-pulse in young speleothems using a soil carbon continuum model

Arid

DOI	10.1016/j.gca.2019.04.029
	Modelling the C-14 bomb-pulse in young speleothems using a soil carbon continuum model
	Markowska, Monika 1,2,3; Fohlmeister, Jens 4,5; Treble, Pauline C.1,2; Baker, Andy 2,6; Andersen, Martin S.2,7; Hua, Quan 1
通讯作者	Markowska, Monika
来源期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
EISSN	1872-9533
出版年	2019
卷号	261 页码:342-367
英文摘要	The 'bomb-pulse' method is a chronological approach to further constrain the age of speleothems that grew between 1950 CE - present. Establishing dependable chronological constraints is crucial for modern calibration studies of speleothems to instrumental climate records, which provides the basis for paleoclimate interpretations. However, a large unknown is how C-14 is transferred from the atmosphere to any individual speleothem owing to the site-specific residence times of organic matter above cave systems. Here, we employ the bomb-pulse method to build chronologies from C-14 measurements in combination with a new unsaturated zone C model which considers C decomposition as a continuum, to better understand unsaturated zone C-14 dynamics. The bomb-pulse curves of eight speleothems from southern Australia in three contrasting climatic regions; the semi-arid Wellington Caves site, the mediterranean Golgotha Cave site and the montane Yarrangobilly Caves site, are investigated. Overall, the modelled C-14 bomb-pulse curves produce excellent fits with measured C-14 speleothem data (r(2) = 0.82-0.99). The C modelling reveals that unsaturated zone C is predominately young at the semi-arid site, with a weighted-mean residence time of 32 years and that tree root respiration is likely an important source of vadose CO2. At the montane site, similar to 39% of C is young (<1 years), but the weighted-mean C ages are older (145-220 years). The mediterranean site has very little contribution from young C (<12%: 0-1 years), with weighted-mean ages between 157 and 245 years, likely due to greater adsorption of organic matter in the upper vadose zone during matrix flow, and remobilisation of C from young syngenetic karst. New end members for low speleothem Dead Carbon Proportion (DCP) are identified (2.19% and 1.65%, respectively) for Australian montane and semi-arid zone speleothems, where oversupply of modern CO2 in the vadose zone leads to lower DCP. It is also demonstrated that DCP can be quite variable over small time scales, that processes may be difficult to untangle and a constant DCP assumption is likely invalid. DCP variability over time is mainly controlled by the changes vadose zone CO2, where vegetation regeneration, wild-fires and karst hydrology play an important role. Crown Copyright (C) 2019 Published by Elsevier Ltd. All rights reserved.
英文关键词	Carbon 14 speleothems vadose zone modelling
类型	Article
语种	英语
国家	Australia ; Germany
收录类别	SCI-E
WOS记录号	WOS:000478786500019
WOS关键词	CAVE DRIPWATER CHEMISTRY ; MEAN RESIDENCE TIME ; ORGANIC-MATTER ; DRIP WATER ; DEAD CARBON ; VADOSE ZONE ; UNSATURATED ZONE ; GOLGOTHA CAVE ; GROUND AIR ; DIOXIDE
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/215908
作者单位	1.ANSTO, Sydney, NSW 2234, Australia; 2.UNSW Sydney, Connected Waters Initiat Res Ctr, Sydney, NSW 2052, Australia; 3.Tubingen Univ, Fac Geosci, D-72074 Tubingen, Germany; 4.Univ Potsdam, Inst Earth & Environm Sci, Karl Liebknecht Str 24, D-14476 Potsdam, Germany; 5.GFZ German Res Ctr Geosci, Sect Climate Dynam & Landscape Dev, D-14473 Potsdam, Germany; 6.UNSW Sydney, Sch Biol Earth & Environm Sci, Sydney, NSW 2052, Australia; 7.UNSW Sydney, Sch Civil & Environm Engn, Sydney, NSW 2052, Australia
推荐引用方式 GB/T 7714	Markowska, Monika,Fohlmeister, Jens,Treble, Pauline C.,et al. Modelling the C-14 bomb-pulse in young speleothems using a soil carbon continuum model[J],2019,261:342-367.
APA	Markowska, Monika,Fohlmeister, Jens,Treble, Pauline C.,Baker, Andy,Andersen, Martin S.,&Hua, Quan.(2019).Modelling the C-14 bomb-pulse in young speleothems using a soil carbon continuum model.GEOCHIMICA ET COSMOCHIMICA ACTA,261,342-367.
MLA	Markowska, Monika,et al."Modelling the C-14 bomb-pulse in young speleothems using a soil carbon continuum model".GEOCHIMICA ET COSMOCHIMICA ACTA 261(2019):342-367.