Open AccessUltra‐small and abundant: Candidate phyla radiation bacteria are potential catalysts of carbon transformation in a thermokarst lake ecosystem
Author(s) -
Vigneron Adrien,
Cruaud Perrine,
Langlois Valérie,
Lovejoy Connie,
Culley Alexander I.,
Vincent Warwick F.
Publication year - 2020
Publication title -
limnology and oceanography letters
Language(s) - English
Resource type - Journals
ISSN - 2378-2242
DOI - 10.1002/lol2.10132
Subject(s) - thermokarst , permafrost , metagenomics , phylum , thaumarchaeota , ecology , environmental chemistry , microbial population biology , archaea , subarctic climate , haloarchaea , biology , biogeochemical cycle , environmental science , bacteria , chemistry , paleontology , biochemistry , gene
The candidate phyla radiation (CPR) is a diverse group of uncultured bacterial lineages with poorly understood metabolic functions. CPR bacteria can represent a large proportion of the total planktonic microbial community in subarctic thermokarst lakes, but their functional roles remain unexplored. We applied sequential water filtration and metagenomic shotgun sequencing to a peatland permafrost thaw lake, and found high proportions of CPR bacteria in both summer and winter (> 40% of 16S rRNA reads in the 0.02–0.22 μ m pore‐size fraction). The metagenome‐assembled genomes of CPR bacteria representatives showed capacities to degrade and ferment permafrost‐ and peatland‐derived organic matter. Potential products of their metabolic activities included acetate, CO 2 , and hydrogen, implying a syntrophic relationship with other community members, including methanogens and methanotrophs. The results indicate biogeochemical interdependencies in organic matter utilization within thermokarst microbial communities, with CPR members playing a key intermediate role in carbon and methane cycling.