DOI: 10.1029/2018GB006057
论文题名: Mercury Cycling in the North Pacific Subtropical Gyre as Revealed by Mercury Stable Isotope Ratios
作者: Motta L.C. ; Blum J.D. ; Johnson M.W. ; Umhau B.P. ; Popp B.N. ; Washburn S.J. ; Drazen J.C. ; Benitez-Nelson C.R. ; Hannides C.C.S. ; Close H.G. ; Lamborg C.H.
刊名: Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224
出版年: 2019
卷: 33, 期: 6 语种: 英语
英文关键词: bioaccumulation
; biogeochemical cycle
; concentration (composition)
; degradation
; food web
; gyre
; isotopic composition
; isotopic ratio
; marine environment
; mercury (element)
; methylation
; nutrient cycling
; pelagic environment
; pollution exposure
; stable isotope
; subtropical region
; zooplankton
; Hawaiian Islands
; Pacific Ocean
; Pacific Ocean (North)
学科: demethylation
; mercury
; mercury at Station ALOHA
; mercury bioaccumulation
; mercury isotopes
; methylation
中文摘要: The oceans are an important global reservoir for mercury (Hg), and marine fish consumption is the dominant human exposure pathway for its toxic methylated form. A more thorough understanding of the global biogeochemical cycle of Hg requires additional information on the mechanisms that control Hg cycling in pelagic marine waters. In this study, Hg isotope ratios and total Hg concentrations are used to explore Hg biogeochemistry in oligotrophic marine environments north of Hawaii. We present the first measurements of the vertical water column distribution of Hg concentrations and the Hg isotopic composition in precipitation, marine particles, and zooplankton near Station ALOHA (22°45′N, 158°W). Our results reveal production and demethylation of methylmercury in both the euphotic (0–175 m) and mesopelagic zones (200–1,000 m). We document a strong relationship between Hg isotopic composition and depth in particles, zooplankton, and fish in the water column and diurnal variations in Δ199Hg values in zooplankton sampled near the surface (25 m). Based on these observations and stable Hg isotope relationships in the marine food web, we suggest that the Hg found in large pelagic fish at Station ALOHA was originally deposited largely by precipitation, transformed into methyl-Hg, and bioaccumulated in situ in the water column. Our results highlight how Hg isotopic compositions reflect abiotic and biotic production and degradation of methyl-Hg throughout the water column and the importance of particles and zooplankton in the vertical transport of Hg. ©2019. 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/160120
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, United States; School of Earth, Ocean and Environment, University of South Carolina, Columbia, SC, United States; Department of Earth Sciences, University of Hawai‘i at Mānoa, Honolulu, HI, United States; Department of Oceanography, University of Hawai‘i at Mānoa, Honolulu, HI, United States; Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States; Department of Ocean Sciences, University of California, Santa Cruz, CA, United States
Recommended Citation:
Motta L.C.,Blum J.D.,Johnson M.W.,et al. Mercury Cycling in the North Pacific Subtropical Gyre as Revealed by Mercury Stable Isotope Ratios[J]. Global Biogeochemical Cycles,2019-01-01,33(6)