Characterization of the Active Bacterial Community Involved in Natural Attenuation Processes in Arsenic-Rich Creek Sediments

Abstract

Acid mine drainage of the Carnoulès mine (France) is characterized by acid waters containing high concentrations of arsenic and iron. In the first 30 m along the Reigous, a small creek draining the site, more than 38% of the dissolved arsenic was removed by co-precipitation with Fe(III), in agreement with previous studies, which suggest a role of microbial activities in the co-precipitation of As(III) and As(V) with Fe(III) and sulfate. To investigate how this particular ecosystem functions, the bacterial community was characterized in water and sediments by 16S rRNA encoding gene library analysis. Based on the results obtained using a metaproteomic approach on sediments combined with high-sensitivity HPLC-chip spectrometry, several GroEL orthologs expressed by the community were characterized, and the active members of the prokaryotic community inhabiting the creek sediments were identified. Many of these bacteria are β-proteobacteria such as Gallionella and Thiomonas, but γ-proteobacteria such as Acidithiobacillus ferrooxidans and α-proteobacteria such as Acidiphilium, Actinobacteria, and Firmicutes were also detected.

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

“…Our biochemical characterization of the Carnoulès ecosystem (Gard, France) supports the existence of multiple abiotic stresses in accordance with previous observations (Casiot et al, , 2004bBruneel et al, 2011). In particular, osmotic stress, low pH and oxidative stress caused by heavy metals and metalloids may explain the reduction in eukaryotic and prokaryotic diversity observed in such ecosystems (Johnson and Hallberg, 2003).…”

Metabolic diversity among main microorganisms inside an arsenic-rich ecosystem revealed by meta- and proteo-genomics

“…Metaproteomic data showed that Carnoulès strains indeed express functions protecting against general and oxidative stress, including superoxide dismutase or thioredoxin, and chaperones such as DnaK or GroEL, which have previously been detected in AMD (Ram et al, 2005;Bruneel et al, 2011). Several proteins such as RecA and DPS involved in DNA recombination and repair were also identified.…”

“…Remaining clones belonged to Firmicutes (4%) and Acidobacteria (3%), and to a lesser extent to classes such as Spirochaetes (1%) and a-Proteobacteria (1%). This demonstrates that the microbial community at Carnoulès includes a few other bacterial Genomic deciphering of an arsenic-rich ecosystem PN Bertin et al phyla in addition to those previously identified (Bruneel et al, 2006(Bruneel et al, , 2011. To decipher the possible role of microorganisms in the biotransformation of toxic elements present at the study site, total DNA extracted from sediments was next fully sequenced.…”

“…In addition, laboratory experiments suggest that bacteria belonging to Thiomonas or Acidithiobacillus genera are involved in this process in situ Casiot et al, 2003;Duquesne et al, 2003;Morin et al, 2003;Egal et al, 2009). However, 16S-based community analyses have revealed that other genera are present in this ecosystem (Duquesne et al, 2003(Duquesne et al, , 2008Bruneel et al, 2003Bruneel et al, , 2006Bruneel et al, , 2008Bruneel et al, , 2011. The biological activity of these uncultured bacteria may have a significant impact on the functioning of this ecosystem.…”

Silicon and Phosphorus Linkage with Iron via Oxygen in the Amorphous Matrix of Gallionella ferruginea Stalks

“…Biotic and/or abiotic depositions of the oxidized form Fe(III) give rise to extracellular, ferric oxide-encrusted, spirally twisted stalks (18,21). The Gallionella cells and associated stalks are found ubiquitously in various aquatic environments such as iron seeps (1), creeks (15), groundwater (30), drinking-water distribution systems (35,44), wetland rhizospheres (56), and acid mine drainage (3).…”