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Six centuries of changing oceanic mercury
Author(s) -
Zhang Yanxu,
Jaeglé Lyatt,
Thompson LuAnne,
Streets David G.
Publication year - 2014
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2014gb004939
Subject(s) - biogeochemical cycle , mercury (programming language) , environmental science , environmental chemistry , coal combustion products , oceanography , particulates , perturbation (astronomy) , sink (geography) , biogeochemistry , coal , atmospheric sciences , chemistry , geology , ecology , biology , geography , computer science , programming language , physics , cartography , organic chemistry , quantum mechanics
Mercury (Hg) is a global and persistent contaminant, affecting human health primarily via marine fish consumption. Large anthropogenic releases of Hg to the atmosphere by mining and coal combustion have resulted in a significant perturbation to the biogeochemical cycling of Hg. The magnitude of this perturbation and the relative roles of the ocean and land as sinks for anthropogenic Hg remain unclear. Here we use a 3‐D global ocean biogeochemical model to show that surface ocean Hg concentrations have increased fourfold over the last 600 years. We find that anthropogenic Hg enters the ocean's interior predominantly by absorption onto sinking organic matter particulates, which decompose and release Hg at a depth of 500–800 m, implying that the human perturbation is largest in subsurface waters of biologically productive regions. Our model simulation predicts that over the last six centuries half of emitted anthropogenic Hg has accumulated in the oceans and marine sediments.