New perspectives on northern microbiomes: viruses in a permafrost thaw ecosystem
Thermokarst ponds
￫ Result from the rapid thawing of permafrost
￫ Are growing in size and number due to global climate change
￫ Produce large amount of greenhouse gases
￫ Gas production varies by season
￫ Due to increased microbial activity
Viruses
￫ Largely understudied in freshwater environments
￫ Responsible for top-down regulation of microbial populations via cell lysis
￫ Catalyze microbial evolution via gene exchange
￫ Can impact biogeochemical cycles
Methods
Water Sampling
￫ Sampling in triplicate over three years
￫ Prefiltration through Sterivex filter (0.22 μm)
￫ Filtration onto an Anotop filter (0.02 μm)
Library and sequencing
￫ DNA extraction with «Backflushing» method
￫ Sequencing on Illumina HiSeq2500 platform
Bioinformatic analysis
￫ Extraction of viral sequences in silico
￫ Clustering of contigs and read mapping
￫ Statistical analysis with Phyloseq
￫ Comparison with lakes from other climatic regions
Boreal – Lake Simoncouche, Québec
Humid continental – Lake Croche, Québec
Temperate oceanic – Lake Lough Neagh
Results and conclusions
Subarctic thaw ponds have two distinct viral communities, an annual one found in summe oxic surface water and a perrenial one found in anoxic winter and summer bottom waters.
Research team
Valérie Langlois1,3,4, Warwick F. Vincent 2,3,4, Alexander Culley1,3,4
(1) Université Laval, Département de biochimie, microbiologie et bio-informatique (2) Université Laval, Département de biologie (3) Centre d’études nordiques (CEN) / Center for northern studies (4) Sentinelle Nord / Sentinel North
Acknowledgements
We would like to thank Alice Lévesque, Vani Mohit and Adrien Vigneron for help with field work and sample treatment. We would also like to thank Brian Boyle and the IBIS sequencing platform and Claude Delziles and the Génome Québec sequencing platform for their assistance and expertise. We thank NSERC, FRQNT, PFSN and Sentinel North for funding support.
