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.
Issued by: Great Lakes Forestry Centre
Catalog ID: 40850
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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.