DOI: 10.1029/2019GB006348
论文题名: A Global Model for Methylmercury Formation and Uptake at the Base of Marine Food Webs
作者: Zhang Y. ; Soerensen A.L. ; Schartup A.T. ; Sunderland E.M.
刊名: Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224
出版年: 2020
卷: 34, 期: 2 语种: 英语
英文关键词: biogeochemistry
; biological uptake
; concentration (composition)
; food web
; global ocean
; methylmercury
; microbial activity
; open ocean
; phytoplankton
; picoplankton
; solar radiation
; trophic status
; Atlantic Ocean
; Pacific Ocean
; Bacillariophyta
; Eukaryota
; Synechococcus
学科: DARWIN
; mercury
; methylmercury
; MITgcm
; trophic transfer
中文摘要: Monomethylmercury (CH3Hg) is the only form of mercury (Hg) known to biomagnify in food webs. Here we investigate factors driving methylated mercury [MeHg = CH3Hg + (CH3)2Hg)] production and degradation across the global ocean and uptake and trophic transfer at the base of marine food webs. We develop a new global 3-D simulation of MeHg in seawater and phyto/zooplankton within the Massachusetts Institute of Technology general circulation model. We find that high modeled MeHg concentrations in polar regions are driven by reduced demethylation due to lower solar radiation and colder temperatures. In the eastern tropical subsurface waters of the Atlantic and Pacific Oceans, the model results suggest that high MeHg concentrations are associated with enhanced microbial activity and atmospheric inputs of inorganic Hg. Global budget analysis indicates that upward advection/diffusion from subsurface ocean provides 17% of MeHg in the surface ocean. Modeled open ocean phytoplankton concentrations are relatively uniform because lowest modeled seawater MeHg concentrations occur in oligotrophic regions with the smallest size classes of phytoplankton, with relatively high uptake of MeHg and vice versa. Diatoms and synechococcus are the two most important phytoplankton categories for transferring MeHg from seawater to herbivorous zooplankton, contributing 35% and 25%, respectively. Modeled ratios of MeHg concentrations between herbivorous zooplankton and phytoplankton are 0.74–0.78 for picoplankton (i.e., no biomagnification) and 2.6–4.5 for eukaryotic phytoplankton. The spatial distribution of the trophic magnification factor is largely determined by the zooplankton concentrations. Changing ocean biogeochemistry resulting from climate change is expected to have a significant impact on marine MeHg formation and bioaccumulation. ©2020. 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/160067
Appears in Collections: 气候变化与战略
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作者单位: Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, China; Harvard John A. Paulson School of Engineering & Applied Sciences, Harvard University, Cambridge, MA, United States; Department of Environmental Health, Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, United States; Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden; Scripps Institution of Oceanography, La Jolla, CA, United States
Recommended Citation:
Zhang Y.,Soerensen A.L.,Schartup A.T.,et al. A Global Model for Methylmercury Formation and Uptake at the Base of Marine Food Webs[J]. Global Biogeochemical Cycles,2020-01-01,34(2)