气候变化领域集成服务门户(CCPortal): Controls on the cadmium isotope composition of modern marine sediments

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DOI	10.1016/j.epsl.2021.116946
	Controls on the cadmium isotope composition of modern marine sediments
	Bryan A.L.; Dickson A.J.; Dowdall F.; Homoky W.B.; Porcelli D.; Henderson G.M.
发表日期	2021
ISSN	0012821X
卷号	565
英文摘要	Continental margin sediments have been identified as the dominant sink in the marine budget of cadmium (Cd). The isotopic composition of this important output flux is, however, unknown. Here we present, with measurements on the Argentine continental margin, the first observational constraints on the isotopic composition of Cd in modern marine oxic and sub-oxic sediments. We identify two main removal mechanisms of Cd; in organic material, and by sulfide formation. Surface margin sediments (0–0.5 cm), with dissolved O2 below detection from ∼0.5 cm, are isotopically lighter than overlying oxygenated waters. A mass balance for these surface sediments indicates that Cd is present dominantly as organically-bound particulate Cd. In sub-surface sediments, Cd concentrations increase in the zone of nitrate reduction, and attain similar isotopic compositions as the water that overlies the sediment (i.e. ∼0.35‰ in deep waters). These observations are consistent with a downward diffusive flux of seawater Cd and redox-driven quantitative removal of that Cd during sulfide precipitation. In combination, these two routes of Cd removal lead to burial of isotopically light organic Cd in margin sub-oxic sediments that enables the global isotopic Cd budget to be balanced. © 2021 Elsevier B.V.
关键词	biogeochemical cadmium cycle cadmium isotopes cadmium sulfides marine waters modern marine sediments trace metal isotopes
英文关键词	Budget control; Precipitation (chemical); Submarine geology; Sulfur compounds; Surficial sediments; Trace elements; Biogeochemical cadmium cycle; Cadmium isotope; Continental margin; Isotope compositions; Isotopic composition; Marine sediments; Marine waters; Modern marine sediment; Surface sediments; Trace metal isotope; Isotopes; biogeochemical cycle; cadmium; continental margin; isotopic composition; marine environment; marine sediment; mass balance; sediment chemistry; sulfide; trace metal; Argentina; Argentinidae
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/203038
作者单位	Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, Ireland; Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, Ireland; School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, Ireland
推荐引用方式 GB/T 7714	Bryan A.L.,Dickson A.J.,Dowdall F.,et al. Controls on the cadmium isotope composition of modern marine sediments[J],2021,565.
APA	Bryan A.L.,Dickson A.J.,Dowdall F.,Homoky W.B.,Porcelli D.,&Henderson G.M..(2021).Controls on the cadmium isotope composition of modern marine sediments.Earth and Planetary Science Letters,565.
MLA	Bryan A.L.,et al."Controls on the cadmium isotope composition of modern marine sediments".Earth and Planetary Science Letters 565(2021).