气候变化领域集成服务门户(CCPortal): A Global Model for Methylmercury Formation and Uptake at the Base of Marine Food Webs

CCPortal

DOI	10.1029/2019GB006348
	A Global Model for Methylmercury Formation and Uptake at the Base of Marine Food Webs
	Zhang Y.; Soerensen A.L.; Schartup A.T.; Sunderland E.M.
发表日期	2020
ISSN	0886-6236
EISSN	1944-9224
卷号	34 期号:2
英文摘要	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.
英文关键词	DARWIN; mercury; methylmercury; MITgcm; trophic transfer
语种	英语
scopus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
来源期刊	Global Biogeochemical Cycles
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/129672
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
推荐引用方式 GB/T 7714	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],2020,34(2).
APA	Zhang Y.,Soerensen A.L.,Schartup A.T.,&Sunderland E.M..(2020).A Global Model for Methylmercury Formation and Uptake at the Base of Marine Food Webs.Global Biogeochemical Cycles,34(2).
MLA	Zhang Y.,et al."A Global Model for Methylmercury Formation and Uptake at the Base of Marine Food Webs".Global Biogeochemical Cycles 34.2(2020).