Enrichment of Cryoconite Hole Anaerobes: Implications for the Subglacial Microbiome.
Glaciers have recently been recognized as ecosystems comprised of several distinct habitats: a sunlit and oxygenated glacial surface, glacial ice, and a dark, mostly anoxic glacial bed. Surface meltwaters annually flood the subglacial sediments by means of drainage channels. Glacial surfaces host aquatic microhabitats called cryoconite holes, regarded as "hot spots" of microbial abundance and activity, largely contributing to the meltwaters' bacterial diversity. This study presents an investigation of cryoconite hole anaerobes and discusses their possible impact on subglacial microbial communities, combining 16S rRNA gene fragment amplicon sequencing and the traditional enrichment culture technique. Cryoconite hole sediment harbored bacteria belonging mainly to the Proteobacteria (21%), Bacteroidetes (16%), Actinobacteria (14%), and Planctomycetes (6%) phyla. An 8-week incubation of those sediments in Postgate C medium for sulfate reducers in airtight bottles, emulating subglacial conditions, eliminated a great majority of dominant taxa, leading to enrichment of the Firmicutes (62%), Proteobacteria (14%), and Bacteroidetes (13%), which consisted of anaerobic genera like Clostridium, Psychrosinus, Paludibacter, and Acetobacterium. Enrichment of Pseudomonas spp. also occurred, suggesting it played a role as a dominant oxygen scavenger, providing a possible scenario for anaerobic niche establishment in subglacial habitats. To our knowledge, this is the first paper to provide insight into the diversity of the anaerobic part of the cryoconite hole microbial community and its potential to contribute to matter turnover in anoxic, subglacial sites.
Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Marek K
MK
Zdanowski
Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Albert
A
Bogdanowicz
Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Jan
J
Gawor
Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Robert
R
Gromadka
Institute of Geochemistry, Mineralogy and Petrology, Faculty of Geology, Warsaw University, Warsaw, Poland.
Dorota
D
Wolicka
Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland. jgrzesiak@arctowski.pl.
Jakub
J
Grzesiak
D039903:Actinobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D000693:Anaerobiosis / Q000502:physiology; D001421:Bacteria, Anaerobic / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D041963:Bacteroidetes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D017753:Ecosystem; D005618:Fresh Water / Q000382:microbiology; D019015:Geologic Sediments / Q000382:microbiology*; D059014:High-Throughput Nucleotide Sequencing; D046448:Ice Cover / Q000382:microbiology*; D061328:Planctomycetales / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D020560:Proteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D012336:RNA, Ribosomal, 16S
Bacteria; Firmicutes; Glacier; Methanogenesis; Psychrophiles