Bouchet S., Goni-Urriza M., Monperrus M., Guyoneaud R., Fernandez P., Heredia C., Tessier E., Gassie C., Point David, Guédron Stéphane, Acha D., Amouroux D. (2018). Linking microbial activities and low-molecular-weight thiols to hg methylation in biofilms and periphyton from high-altitude tropical lakes in the Bolivian altiplano. Environmental Science and Technology, 52 (17), p. 9758-9767. ISSN 0013-936X.
Titre du document
Linking microbial activities and low-molecular-weight thiols to hg methylation in biofilms and periphyton from high-altitude tropical lakes in the Bolivian altiplano
Année de publication
2018
Auteurs
Bouchet S., Goni-Urriza M., Monperrus M., Guyoneaud R., Fernandez P., Heredia C., Tessier E., Gassie C., Point David, Guédron Stéphane, Acha D., Amouroux D.
Source
Environmental Science and Technology, 2018,
52 (17), p. 9758-9767 ISSN 0013-936X
The sources and factors controlling concentrations of monomethylmercury (MMHg) in aquatic ecosystems need to be better understood. Here, we investigated Hg transformations in sediments, periphyton associated with green algae's or aquatic plants, and benthic biofilms from the Lake Titicaca hydrosystem and compared them to the occurrence of active methylating microorganisms and extracellular Hg ligands. Intense Hg methylation was found in benthic biofilms and green algae's periphyton, while it remained low in sediments and aquatic plants' periphyton. Demethylation varied between compartments but remained overall in the same range. Hg methylation was mainly carried out by sulfate reducers, although methanogens also played a role. Its variability between compartments was first explained by the presence or absence of the hgcAB genes. Next, both benthic biofilm and green algae's periphyton exhibited a great diversity of extracellular low-molecular-weight (LMW) thiols (13 or 14 compounds) present at a range of a few nmol L-1 or mu mol L-1 but clearly dominated by cysteine and 3-mercaptopropionic acid. Hg methylation was overall positively correlated to the total thiol concentrations, albeit to different extents according to the compartment and conditions. This work is the first examining the interplay between active methylating bacterial communities and extracellular ligands in heterotrophic biofilms and supports the involvement of LMW thiols in Hg methylation in real aquatic systems.
Plan de classement
Ecologie, systèmes aquatiques [036]
;
Biotechnologies [084]
Description Géographique
BOLIVIE ; TITICACA LAC ; ZONE TROPICALE
Localisation
Fonds IRD [F B010074019]
Identifiant IRD
fdi:010074019
