Methylmercury photodegradation influenced by sea-ice cover in Arctic marine ecosystems

被引：0

作者：

Point D. ^{[1
,2
]}

Sonke J.E. ^{[2
]}

Day R.D. ^{[1
]}

Roseneau D.G. ^{[3
]}

Hobson K.A. ^{[4
]}

Vander Pol S.S. ^{[1
]}

Moors A.J. ^{[1
]}

Pugh R.S. ^{[1
]}

Donard O.F.X. ^{[5
]}

Becker P.R. ^{[1
]}

机构：

[1] National Institute of Standards and Technology (NIST), Hollings Marine Laboratory, Charleston

[2] Laboratoire des Mécanismes et Transferts en Géologie (LMTG), Observatoire Midi-Pyrénées, Université Paul Sabatier

[3] US Fish AndWildlife Service, Alaska Maritime NationalWildlife Refuge, Homer

[4] Environment Canada, Saskatoon

[5] Institut Pluridisciplinaire de Recherche sur l'Environnement et les Materiaux, Equipe de Chimie Analytique BioInorganique et Environnement, UMR CNRS 5254

来源：

Nature Geoscience | 2011年 / 4卷 / 3期

关键词：

D O I：

10.1038/ngeo1049

中图分类号：

学科分类号：

摘要：

Atmospheric deposition of mercury to remote areas has increased threefold since pre-industrial times. Mercury deposition is particularly pronounced in the Arctic. Following deposition to surface oceans and sea ice, mercury can be converted into methylmercury, a biologically accessible form of the toxin, which biomagnifies along the marine food chain. Mass-independent fractionation of mercury isotopes accompanies the photochemical breakdown of methylmercury to less bioavailable forms in surface waters. Here we examine the isotopic composition of mercury in seabird eggs collected from colonies in the North Pacific Ocean, the Bering Sea and the western Arctic Ocean, to determine geographical variations in methylmercury breakdown at northern latitudes. We find evidence for mass-independent fractionation of mercury isotopes. The degree of mass-independent fractionation declines with latitude. Foraging behaviour and geographic variations in mercury sources and solar radiation fluxes were unable to explain the latitudinal gradient. However, mass-independent fractionation was negatively correlated with sea-ice cover. We conclude that sea-ice cover impedes the photochemical breakdown of methylmercury in surface waters, and suggest that further loss of Arctic sea ice this century will accelerate sunlight-induced breakdown of methylmercury in northern surface waters. © 2011 Macmillan Publishers Limited. All rights reserved.

引用

页码：188 / 194

页数：6

共 49 条

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