DOI: 10.1038/ngeo1918
论文题名: Methylmercury production below the mixed layer in the North Pacific Ocean
作者: Blum J.D. ; Popp B.N. ; Drazen J.C. ; Anela Choy C. ; Johnson M.W.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2013
卷: 6, 期: 10 起始页码: 879
结束页码: 884
语种: 英语
Scopus关键词: biological production
; coastal sediment
; food web
; isotopic composition
; marine environment
; methylmercury
; microbial activity
; mixed layer
; Pacific Ocean
; Pacific Ocean (North)
英文摘要: Mercury enters marine food webs in the form of microbially generated monomethylmercury. Microbial methylation of inorganic mercury, generating monomethylmercury, is widespread in low-oxygen coastal sediments. The degree to which microbes also methylate mercury in the open ocean has remained uncertain, however. Here, we present measurements of the stable isotopic composition of mercury in nine species of marine fish that feed at different depths in the central North Pacific Subtropical Gyre. We document a systematic decline in δ 202 Hg, Δ 199 Hg and Δ 201 Hg values with the depth at which fish feed. We show that these mercury isotope trends can be explained only if monomethylmercury is produced below the surface mixed layer, including in the underlying oxygen minimum zone, that is, between 50 and more than 400 m depth. Specifically, we estimate that about 20-40% of the monomethylmercury detected below the surface mixed layer originates from the surface and enters deeper waters either attached to sinking particles, or in zooplankton and micronekton that migrate to depth. We suggest that the remaining monomethylmercury found at depth is produced below the surface mixed layer by methylating microbes that live on sinking particles. We suggest that microbial production of monomethylmercury below the surface mixed later contributes significantly to anthropogenic mercury uptake into marine food webs. © 2013 Macmillan Publishers Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106690
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Department of Earth and Environmental Sciences, University of Michigan, 1100 N University Avenue, Ann Arbor, MI 48109, United States; Department of Geology and Geophysics, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822, United States; Department of Oceanography, University of Hawaii, 1000 Pope Road, Honolulu, HI 96822, United States
Recommended Citation:
Blum J.D.,Popp B.N.,Drazen J.C.,et al. Methylmercury production below the mixed layer in the North Pacific Ocean[J]. Nature Geoscience,2013-01-01,6(10)