DOI: 10.1029/2018GB005942
论文题名: Deciphering the Role of Water Column Redoxclines on Methylmercury Cycling Using Speciation Modeling and Observations From the Baltic Sea
作者: Soerensen A.L. ; Schartup A.T. ; Skrobonja A. ; Bouchet S. ; Amouroux D. ; Liem-Nguyen V. ; Björn E.
刊名: Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224
出版年: 2018
卷: 32, 期: 10 语种: 英语
英文关键词: anoxic conditions
; bioaccumulation
; bioavailability
; experimental study
; incubation
; iron
; mercury (element)
; methylation
; methylmercury
; oxygen
; redox conditions
; speciation (chemistry)
; sulfide
; sulfur
; toxicity
; water column
; zooplankton
; Atlantic Ocean
; Baltic Sea
学科: anoxia
; hypoxia
; mercury
; methylation
; methylmercury
; redoxcline
中文摘要: Oxygen-depleted areas are spreading in coastal and offshore waters worldwide, but the implication for production and bioaccumulation of neurotoxic methylmercury (MeHg) is uncertain. We combined observations from six cruises in the Baltic Sea with speciation modeling and incubation experiments to gain insights into mercury (Hg) dynamics in oxygen depleted systems. We then developed a conceptual model describing the main drivers of Hg speciation, fluxes, and transformations in water columns with steep redox gradients. MeHg concentrations were 2–6 and 30–55 times higher in hypoxic and anoxic than in normoxic water, respectively, while only 1–3 and 1–2 times higher for total Hg (THg). We systematically detected divalent inorganic Hg (HgII) methylation in anoxic water but rarely in other waters. In anoxic water, high concentrations of dissolved sulfide cause formation of dissolved species of HgII: HgS2H− (aq) and Hg (SH)2 0 (aq). This prolongs the lifetime and increases the reservoir of HgII readily available for methylation, driving the high MeHg concentrations in anoxic zones. In the hypoxic zone and at the hypoxic-anoxic interface, Hg concentrations, partitioning, and speciation are all highly dynamic due to processes linked to the iron and sulfur cycles. This causes a large variability in bioavailability of Hg, and thereby MeHg concentrations, in these zones. We find that zooplankton in the summertime are exposed to 2–6 times higher MeHg concentrations in hypoxic than in normoxic water. The current spread of hypoxic zones in coastal systems worldwide could thus cause an increase in the MeHg exposure of food webs. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/160190
Appears in Collections: 气候变化与战略
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作者单位: Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States; Department of Chemistry, Umeå University, Umeå, Sweden; Now at D-USYS Department, ETH Zürich, Zürich, Switzerland; Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Materiaux, CNRS/UNIV PAU & PAYS ADOUR, Pau, France; School of Science and Technology, Örebro University, Örebro, Sweden
Recommended Citation:
Soerensen A.L.,Schartup A.T.,Skrobonja A.,et al. Deciphering the Role of Water Column Redoxclines on Methylmercury Cycling Using Speciation Modeling and Observations From the Baltic Sea[J]. Global Biogeochemical Cycles,2018-01-01,32(10)