Mercury transformation by anaerobic bacterial communities selected from estuarine sediments
Résumé
The fate of mercury species in the environment strongly depends on microbial activities and environmental conditions. Methylation esp. is one of the major processes, which transform the inorg. forms of the metal into toxic and easily bioaccumulated org. forms. Thus, we designed an exptl. setup to study mercury biotransformation in estuarine ecosystems. Sediments were incubated in slurries and polluted with inorg. mercury (HgCl2). Mercury methylation was obsd. only in slurries maintained under anoxic conditions. The main microbial populations were isolated and identified by partial sequencing of 16S rDNA. The methylation, studied by gas chromatog.-inductively coupled plasma mass spectrometry, demonstrated that only sulfate-reducing bacteria were the methylators among this community, which also comprise denitrifiers and fermentative bacteria.