Canadian Forest Service Publications

Viruses direct carbon cycling in lake sediments under global change. Braga, L.P.P., Orland, C., Emilson. E.J.S., Fitch, A.A., Osterholz, H., Dittmar, T., Basiliko, N., Mykytczuk, N.C.S., Tanentzap, A.J.T. Proc. of the National Academy of Sciences. 2022, Oct 11. 119(41): 12 p.

Year: 2022

Issued by: Great Lakes Forestry Centre

Catalog ID: 40850

Language: English

Availability: Not available through the CFS (click for more information).

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Plain Language Summary

Global change is altering the vast amount of carbon cycled by microbes between land and freshwater, but how viruses mediate this process is poorly understood. Here, we show that viruses direct carbon cycling in lake sediments, and these impacts intensify with future changes in water clarity and forest runoff. Using experimental gradients within sediments of a clear and a dark boreal lake, we identified 156 viral operational taxonomic units (vOTUs) which were associated with dissolved organic matter (DOM) composition and greenhouse gas (GHG) concentrations. Virus-like particles were also associated with reduced bacterial metabolism and shifts in, likely released by cell lysis rather than higher molecular mass compounds accumulating from reduced degradation. An additional 9.6% of vOTUs harbored auxiliary metabolic genes associated with DOM and GHGs. Taken together, these different effects on host dynamics and metabolism can explain why abundances of vOTUs rather than MAGs were better overall predictors of carbon cycling. Future increases in forest runoff will change viral composition and function with consequences for DOM pools. Given their importance, viruses must now be explicitly considered in efforts to understand and predict the freshwater carbon cycle and its future under global environmental change.