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Historical variations of mercury stable isotope ratios in Arctic glacier firn and ice cores
Author(s) -
Zdanowicz C. M.,
Krümmel E. M.,
Poulain A. J.,
Yumvihoze E.,
Chen J.,
Štrok M.,
Scheer M.,
Hintelmann H.
Publication year - 2016
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 - 10.1002/2016gb005411
Subject(s) - ice core , glacier , firn , arctic , mercury (programming language) , cryosphere , sea ice , snow , arctic ice pack , oceanography , geology , environmental science , atmospheric sciences , physical geography , geomorphology , computer science , geography , programming language
The concentration and isotopic composition of mercury (Hg) were determined in glacier core samples from Canadian Arctic ice caps dating from preindustrial to recent time (early 21st century). Mean Hg levels increased from ≤ 0.2 ng L −1 in preindustrial time to ~0.8–1.2 ng L −1 in the modern industrial era (last ~200 years). Hg accumulated on Arctic ice caps has Δ 199 Hg and Δ 201 Hg that are higher (~ −1 to 2.9‰) than previously reported for Arctic snow impacted by atmospheric Hg depletion events (mostly < −1‰), suggesting that these events contribute little to Hg accumulation on ice caps. The range of δ 202 Hg, Δ 199 Hg, and Δ 201 Hg in glacier cores overlaps with that of Arctic Hg 0 (g) and of seawater in Baffin Bay and also with that of midlatitude precipitation and industrial Hg sources, including coal and Hg ores. A core from Agassiz ice cap (80.7°N) shows a ~ +1‰ shift in δ 202 Hg over the nineteenth to twentieth centuries that could reflect changes in the isotopic composition of the atmospheric Hg pool in the High Arctic in response to growing industrial emissions at lower latitudes. This study is the first ever to report on historical variations of Hg stable isotope ratios in Arctic ice cores. Results could help constrain future modeling efforts of the global Hg biogeochemical cycle and the atmosphere's response to changing Hg emissions, past and future.