| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
A Michaelis–Menten type equation for describing methylmercury dependence on inorganic mercury in aquatic sediments
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| Autores: |
Cossa, Daniel
Garnier, Cedric
Buscail, Roselyne
Elbaz-poulichet, Francoise
Mikac, Nevenka
Patel-sorrentino, Nathalie
Tessier, Erwan
Rigaud, Sylvain
Lenoble, Veronique
Gobeil, Charles
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| Data: |
2014-06
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| Ano: |
2014
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| Palavras-chave: |
Mercury
Methylmercury
Aquatic sediment
Methylation
Demethylation
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| Resumo: |
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 By compiling 1,442 published and unpublished HgT–MeHg couples from lacustrine, riverine, estuarine and marine sediments covering various environmental conditions, from deep pristine abyssal to heavily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.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
http://archimer.ifremer.fr/doc/00171/28220/26520.pdf
DOI:10.1007/s10533-013-9924-3
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| Editor: |
Springer
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| Relação: |
http://archimer.ifremer.fr/doc/00171/28220/
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| Formato: |
application/pdf
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| Fonte: |
Biogeochemistry (0168-2563) (Springer), 2014-06 , Vol. 119 , N. 1-3 , P. 35-43
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| Direitos: |
Springer Science+Business Media Dordrecht 2013
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