Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat

• DOI: 10.3389/fmicb.2014.00011
• Publication Date: 2014-01-27T04:09:25Z
• Authors: Jerome T. Babauta; Erhan Atci; Phuc T. Ha; Stephen R. Lindemann; Timothy Ewing; Douglas R. Call; James K. Fredrickson; Haluk Beyenal
• Keywords: Microbial mat

Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate respiration on specific electron acceptors as a function of depth. In this work, benthic phototrophic mat from Hot Lake, hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop microscale electrochemical method study local transfer processes within the mat. To characterize physicochemical variables influencing transfer, we initially quantified potential, pH and dissolved oxygen by depth under photic aphotic conditions. We further demonstrated power output fuel cell light-dependent. processes, deployed electrode (microelectrode) with tip size ~20 µm. enrich subset microorganisms capable interacting microelectrode, anodically polarized microelectrode Subsequently, microelectrode-associated community compare it neighboring community, performed amplicon sequencing V1-V3 region 16S gene. Differences Bray-Curtis beta diversity, illustrated large changes relative abundance at phylum level, suggested successful enrichment members surface. The exhibited substantially reduced alpha diversity elevated abundances Prosthecochloris, Loktanella, Catellibacterium, other unclassified Rhodobacteraceae, Thiomicrospira, Limnobacter, compared an equivalent Our results suggest selected for population, more sulfur-oxidizing phylotypes community.