Functional redundancy imparts process stability to acidic Fe(II)‐oxidizing microbial reactors

Abstract

In previous work, lab-scale reactors designed to study microbial Fe(II) oxidation rates at low pH were found to have stable rates under a wide range of pH and Fe(II) concentrations. Since the stirred reactor environment eliminates many of the temporal and spatial variations that promote high diversity among microbial populations in nature, we were surprised that the reactors supported multiple taxa presumed to be autotrophic Fe(II) oxidizers based on their phylogeny. Metagenomic analyses of the reactor communities revealed differences in the metabolic potential of these taxa with respect to Fe(II) oxidation and carbon fixation pathways, acquisition of potentially growth-limiting substrates and the ability to form biofilms. Our findings support the hypothesis that the long-term co-existence of multiple autotrophic Fe(II)oxidizing populations in the reactors are due to distinct metabolic potential that supports differential growth in response to limiting resources such as nitrogen, phosphorus and oxygen. Our data also highlight the role of biofilms in creating spatially distinct geochemical niches that enable the coexistence of multiple taxa that occupy the same apparent metabolic niche when the system is viewed in bulk. The distribution of key metabolic functions across different co-existing taxa supported functional redundancy and imparted process stability to these reactors.

Anthropogenic activities change the relationship between microbial community taxonomic composition and functional attributes

“…It ensures that ecosystem processes continue following environmental disturbance, which potentially cause temporary or permanent local species extinctions (Biggs et al ., 2020). Many studies have detected functional redundancy in microbial communities (Galambos et al ., 2019; Ayala‐Muñoz et al ., 2020). However, recent studies found strong correlations between microbial community composition and function in both marine and freshwater ecosystems (Delgado‐Baquerizo et al ., 2016; Galand et al ., 2018).…”

Procesos de remediación y recuperación de metales pesados utilizando comunidades microbianas extremófilas

“…Probablemente, la redundancia funcional observada en la región de Caviahue-Copahue está originada en su naturaleza altamente inestable y extrema. Esta condición es esperable en los ambientes naturales cuyas condiciones fluctúan frecuentemente: las comunidades microbianas autóctonas deberían ser redundantes para evitar que el sistema colapse rápidamente (Mori et al, 2013;Louca et al, 2018;Avila-Jimenez et al, 2020;Ayala-Muñoz et al, 2021). Para confirmar esta hipótesis son necesarios estudios metagenómicos (más allá del gen 16S ARNr) y transcriptómicos que están fuera del alcance de este trabajo de tesis.…”