DOI: 10.1029/2019GB006323
论文题名: Importance of Cadmium Sulfides for Biogeochemical Cycling of Cd and Its Isotopes in Oxygen Deficient Zones—A Case Study of the Angola Basin
作者: Guinoiseau D. ; Galer S.J.G. ; Abouchami W. ; Frank M. ; Achterberg E.P. ; Haug G.H.
刊名: Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224
出版年: 2019
卷: 33, 期: 12 语种: 英语
英文关键词: biogeochemical cycle
; cadmium
; complexation
; isotopic analysis
; isotopic fractionation
; ligand
; marine sediment
; mixing
; oxygen
; sulfide
; tracer
; water mass
; Angola Basin
; Atlantic Ocean
; Atlantic Ocean (South)
; Cape Basin
; Bacteria (microorganisms)
学科: Angola Basin oxygen deficient zone (ODZ)
; cadmium isotopes
; cadmium sulfides
; GEOTRACES GA08
中文摘要: Understanding oceanic cadmium (Cd) cycling is paramount due to its micronutrient-like behavior in seawater, which has been inferred from its similarity to phosphate (PO4) cycling. Cadmium concentrations follow a nutrient-like consumption-regeneration cycle in the top of the water column and are mainly controlled by water mass mixing and circulation in the deep ocean. However, an additional scavenging mechanism through cadmium sulfide (CdS) precipitates, occurring within sinking biogenic particles in oxygen deficient zones (ODZ), has been proposed. In this study, we report Cd stable isotope and concentration data for seven vertical seawater profiles sampled during GEOTRACES cruise GA08 in the northern Cape and Angola Basins, which feature a significant ODZ along their eastern margins. Outside the ODZ, Cd cycling is similar to that previously reported for the South Atlantic. While water mass mixing largely controls deep ocean Cd isotope signatures, Cd isotope fractionation in surface waters can be modeled as an open system at steady state buffered by organic ligand complexation. In the ODZ, stronger Cd depletion relative to PO4 is associated with a shift in δ114Cd toward heavier values, which is indicative of CdS precipitation. Our interpretation is supported by experimental CdS precipitation data and a size-resolved particle model involving bacterial sulfate reduction as a precursor of CdS. Our estimates of the CdS flux to the seafloor (107 to 109 mol/yr) indicate that CdS precipitation is a significant process of Cd removal and constitutes a nonnegligible Cd sink that needs to be better quantified by Cd isotope analyses of marine sediments. ©2019. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/160077
Appears in Collections: 气候变化与战略
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作者单位: Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany; Now at Institut de Physique du Globe de Paris, Université de Paris, Paris, France; Institut für Geologie und Mineralogie, Universität zu Köln, Cologne, Germany; GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany
Recommended Citation:
Guinoiseau D.,Galer S.J.G.,Abouchami W.,et al. Importance of Cadmium Sulfides for Biogeochemical Cycling of Cd and Its Isotopes in Oxygen Deficient Zones—A Case Study of the Angola Basin[J]. Global Biogeochemical Cycles,2019-01-01,33(12)