A Michaelis–Menten type equation for describing methylmercury dependence on inorganic mercury in aquatic sediments
| Type | Article | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Date | 2014-06 | ||||||||||||
| Language | English | ||||||||||||
| Author(s) | Cossa Daniel1, Garnier Cedric2, Buscail Roselyne3, Elbaz-Poulichet Francoise4, 5, Mikac Nevenka6, Patel-Sorrentino Nathalie2, Tessier Erwan2, Rigaud Sylvain7, Lenoble Veronique2, Gobeil Charles8 | ||||||||||||
| Affiliation(s) | 1 : IFREMER, F-83507 La Seyne Sur Mer, France. 2 : Univ Toulon & Var, PROTEE, EA 3819, F-83957 La Garde, France. 3 : Univ Perpignan, CEFREM CNRS UMR 5110, F-66860 Perpignan, France. 4 : Univ Montpellier I, Lab Hydrosci, UMR CNRS, CC MSE, F-34095 Montpellier 5, France. 5 : Univ Montpellier 2, Lab Hydrosci, UMR CNRS, CC MSE, F-34095 Montpellier 5, France. 6 : Rudjer Boskovic Inst, Ctr Marine & Environm Res, Zagreb 10000, Croatia. 7 : Aix Marseille Univ, Cerege, F-13545 Aix En Provence 04, France. 8 : Univ Quebec, INRS ETE, Quebec City, PQ G1K 9A9, Canada. |
||||||||||||
| Source | Biogeochemistry (0168-2563) (Springer), 2014-06 , Vol. 119 , N. 1-3 , P. 35-43 | ||||||||||||
| DOI | 10.1007/s10533-013-9924-3 | ||||||||||||
| WOS© Times Cited | 27 | ||||||||||||
| Note | Electronic supplementary material The online version of this article (doi:10.1007/s10533-013-9924-3) contains supplementary material, which is available to authorized users. | ||||||||||||
| Keyword(s) | Mercury, Methylmercury, Aquatic sediment, Methylation, Demethylation | ||||||||||||
| Abstract | Methylation of mercury (Hg) is the crucial process that controls Hg biomagnification along the aquatic food chains. Aquatic sediments are of particular interest because they constitute an essential reservoir where inorganic divalent Hg (HgII) is methylated. Methylmercury (MeHg) concentrations in sediments mainly result from the balance between methylation and demethylation reactions, two opposite natural processes primarily mediated by aquatic microorganisms. Thus, Hg availability and the activity of methylating microbial communities control the MeHg abundance in sediments. Consistently, some studies have reported a significant positive correlation between MeHg and HgII or total Hg (HgT), taken as a proxy for HgII, in aquatic sediments using enzyme-catalyzed methylation/demethylation mechanisms. By compiling 1,442 published and unpublished HgT–MeHg couples from lacustrine, riverine, estuarine and marine sediments covering various environmental conditions, from deep pristine abyssal to heavily contaminated riverine sediments, we show that a Michaelis–Menten type relationship is an appropriate model to relate the two parameters: MeHg = aHgT/(K m + HgT), with a = 0.277 ± 0.011 and K m = 188 ± 15 (R 2 = 0.70, p < 0.001). From K m variations, which depend on the various encountered environmental conditions, it appears that MeHg formation and accumulation are favoured in marine sediments compared to freshwater ones, and under oxic/suboxic conditions compared to anoxic ones, with redox potential and organic matter lability being the governing factors. | ||||||||||||
| Full Text |
|