Oxygen-dependent niche formation of a pyrite-dependent acidophilic consortium built by archaea and bacteria

Abstract

Biofilms can provide a number of different ecological niches for microorganisms. Here, a multispecies biofilm was studied in which pyrite-oxidizing microbes are the primary producers. Its stability allowed not only detailed fluorescence in situ hybridization (FISH)-based characterization of the microbial population in different areas of the biofilm but also to integrate these results with oxygen and pH microsensor measurements conducted before. The O 2 concentration declined rapidly from the outside to the inside of the biofilm. Hence, part of the population lives under microoxic or anoxic conditions. Leptospirillum ferrooxidans strains dominate the microbial population but are only located in the oxic periphery of the snottite structure. Interestingly, archaea were identified only in the anoxic parts of the biofilm. The archaeal community consists mainly of so far uncultured Thermoplasmatales as well as novel ARMAN (Archaeal Richmond Mine Acidophilic Nanoorganism) species. Inductively coupled plasma analysis and X-ray absorption near edge structure spectra provide further insight in the biofilm characteristics but revealed no other major factors than oxygen affecting the distribution of bacteria and archaea. In addition to catalyzed reporter deposition FISH and oxygen microsensor measurements, microautoradiographic FISH was used to identify areas in which active CO 2 fixation takes place. Leptospirilla as well as acidithiobacilli were identified as primary producers. Fixation of gaseous CO 2 seems to proceed only in the outer rim of the snottite. Archaea inhabiting the snottite core do not seem to contribute to the primary production. This work gives insight in the ecological niches of acidophilic microorganisms and their role in a consortium. The data provided the basis for the enrichment of uncultured archaea.

15N‐ and 2H proteomic stable isotope probing links nitrogen flow to archaeal heterotrophic activity

“…Heterotrophic metabolisms have been demonstrated for some of the Archaea in enrichments cultures, as well as with pure cultures of ‘ Ferroplasma acidarmanus ’ (Dopson et al ., ; Ziegler et al ., ). Previous work has shown that the Thermoplasmatales come to dominate the community in submerged biofilms (Justice et al ., ), and the increased abundance of Thermoplasmatales protein in Fe 3+ ‐containing environments indicates that Fe 3+ is an important factor in this transition.…”

Sulfate reducing bioreactor dependence on organic substrates for remediation of coal-generated acid mine drainage: Field experiments

“…The stimulation of members of the Gammaproteobacteria, Betaproteobacteria, and Alphaproteobacteria, which possess members capable of iron cycling and sulfur oxidation (Baker and Banfield, 2003;Hedrich et al, 2011;Johnson et al, 2012), suggests that precipitate formation within the organic substrate-containing reactors may have occurred over the duration of the field trial possibly limiting OC substrate availability. While anaerobic conditions are necessary for active sulfate reduction and microaerophilic conditions are necessary for iron and sulfur oxidation under low-pH conditions, the concurrence of these two disparate metabolisms may be explained by microniche or biofilm formation within the system (Bertis and Ziebis, 2010;Desai et al, 2013;Ziegler et al, 2013). Future studies will require OC analysis of the reactors as well as further research into the attached versus planktonic microbial community to determine the dynamics occurring within the bioreactors.…”

Extremophile microbiomes in acidic and hypersaline river sediments of Western Australia

“…Because Fe(III) hydroxide minerals schwertmannite and K-jarosite were observed in the river sediment, the Aplasma-related archaeal lineage is inferred to be one of the primary drivers of Fe(II) oxidation in West Dalyup River. These archaeal communities were distinct from those detected in other hypersaline or acidic environments (Baker and Banfield, 2003;Tyson et al, 2004;Ram et al, 2005;Baker et al, 2006;Oren, 2008;Comolli et al, 2009;Andrei et al, 2012;Emmerich et al, 2012;Narasingarao et al, 2012;Yelton et al, 2013;Ziegler et al, 2013;Méndez-García et al, 2014).…”