%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Masbou, J.
%A Point, David
%A Sonke, J. E.
%A Frappart, F.
%A Perrot, V.
%A Amouroux, D.
%A Richard, P.
%A Becker, P. R.
%T Hg stable isotope time trend in ringed seals registers decreasing sea ice cover in the Alaskan arctic
%D 2015
%L fdi:010064923
%G ENG
%J Environmental Science and Technology
%@ 0013-936X
%K ETATS UNIS ; ALASKA ; ARCTIQUE
%M ISI:000359278400007
%N 15
%P 8977-8985
%R 10.1021/es5048446
%U https://www.documentation.ird.fr/hor/fdi:010064923
%> https://www.documentation.ird.fr/intranet/publi/2015/09/010064923.pdf
%V 49
%W Horizon (IRD)
%X Decadal time trends of mercury (Hg) concentrations in Arctic biota suggest that anthropogenic Hg is not the single dominant factor modulating Hg exposure to Arctic wildlife. Here, we present Hg speciation (monomethyl-Hg) and stable isotopic composition (C, N, Hg) of 53 Alaskan ringed seal liver samples covering a period of 14 years (1988-2002). In vivo metabolic effects and foraging ecology explain most of the observed 1.6 parts per thousand variation in liver delta Hg-202, but not Delta Hg-199. Ringed seal habitat use and migration were the most likely factors explaining Delta Hg-199 variations. Average Delta Hg-199 in ringed seal liver samples from Barrow increased significantly from +0.38 +/- 0.08%0 (+/- SE, n = 5) in 1988 to +0.59 +/- 0.07 parts per thousand (+/- SE, n = 7) in 2002 (4.1 +/- 1.2% per year, p < 0.001). Delta Hg-199 in marine biological tissues is thought to reflect marine Hg photochemistry before biouptake and bioaccumulation. A spatiotemporal analysis of sea ice cover that accounts for the habitat of ringed seals suggests that the observed increase in Delta Hg-199 may have been caused by the progressive summer sea ice disappearance between 1988 and 2002. While changes in seal liver Delta Hg-199 values suggests a mild sea ice control on marine MMHg breakdown, the effect is not large enough to induce measurable HgT changes in biota. This suggests that Hg trends in biota in the context of a warming Arctic are likely controlled by other processes.
%$ 036 ; 034 ; 021