Warming Climate Is Reducing the Diversity of Dominant Microbes in the Largest High Arctic Lake

• Published in: Frontiers in Microbiology
• Main Authors: Graham A. Colby, Matti O. Ruuskanen, Kyra A. St.Pierre, Vincent L. St.Louis, Alexandre J. Poulain, Stéphane Aris-Brosou
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2020
• Subjects: high arctic; microbial ecology; metagenome assembled genomes (MAGs); high-throughput sequencing; climate change; Microbiology; QR1-502; Arctic; Arctic Lake; Canada; Lake Hazen; Climate change; glacier*
• Online Access: https://doi.org/10.3389/fmicb.2020.561194; https://doaj.org/article/00c0f2bd14a24a758432d5c81047663c

Temperatures in the Arctic are expected to increase dramatically over the next century, and transform high latitude watersheds. However, little is known about how microbial communities and their underlying metabolic processes will be affected by these environmental changes in freshwater sedimentary systems. To address this knowledge gap, we analyzed sediments from Lake Hazen, NU Canada. Here, we exploit the spatial heterogeneity created by varying runoff regimes across the watershed of this uniquely large high-latitude lake to test how a transition from low to high runoff, used as one proxy for climate change, affects the community structure and functional potential of dominant microbes. Based on metagenomic analyses of lake sediments along these spatial gradients, we show that increasing runoff leads to a decrease in taxonomic and functional diversity of sediment microbes. Our findings are likely to apply to other, smaller, glacierized watersheds typical of polar or high latitude ecosystems; we can predict that such changes will have far reaching consequences on these ecosystems by affecting nutrient biogeochemical cycling, the direction and magnitude of which are yet to be determined.