Biogeochemical dynamics and microbial community development under sulfate- and iron-reducing conditions based on electron shuttle amendment.

Autor: Flynn TM; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America., Antonopoulos DA; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America., Skinner KA; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America., Brulc JM; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America., Johnston E; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America., Boyanov MI; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America.; Institute of Chemical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria., Kwon MJ; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America.; Department of Earth and Environmental Sciences, Korea University, Seoul, South Korea., Kemner KM; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America., O'Loughlin EJ; Biosciences Division, Argonne National Laboratory, Lemont, Illinois, United States of America.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2021 May 20; Vol. 16 (5), pp. e0251883. Date of Electronic Publication: 2021 May 20 (Print Publication: 2021).
DOI: 10.1371/journal.pone.0251883
Abstrakt: Iron reduction and sulfate reduction are two of the major biogeochemical processes that occur in anoxic sediments. Microbes that catalyze these reactions are therefore some of the most abundant organisms in the subsurface, and some of the most important. Due to the variety of mechanisms that microbes employ to derive energy from these reactions, including the use of soluble electron shuttles, the dynamics between iron- and sulfate-reducing populations under changing biogeochemical conditions still elude complete characterization. Here, we amended experimental bioreactors comprised of freshwater aquifer sediment with ferric iron, sulfate, acetate, and the model electron shuttle AQDS (9,10-anthraquinone-2,6-disulfonate) and monitored both the changing redox conditions as well as changes in the microbial community over time. The addition of the electron shuttle AQDS did increase the initial rate of FeIII reduction; however, it had little effect on the composition of the microbial community. Our results show that in both AQDS- and AQDS+ systems there was an initial dominance of organisms classified as Geobacter (a genus of dissimilatory FeIII-reducing bacteria), after which sequences classified as Desulfosporosinus (a genus of dissimilatory sulfate-reducing bacteria) came to dominate both experimental systems. Furthermore, most of the ferric iron reduction occurred under this later, ostensibly "sulfate-reducing" phase of the experiment. This calls into question the usefulness of classifying subsurface sediments by the dominant microbial process alone because of their interrelated biogeochemical consequences. To better inform models of microbially-catalyzed subsurface processes, such interactions must be more thoroughly understood under a broad range of conditions.
Competing Interests: The authors have declared that no competing interests exist.
Databáze: MEDLINE
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