| Autor: |
Braga LPP; Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom.; Institute of Chemistry, University of Sao Paulo, Sao Paulo 05508-900, Brazil., Orland C; Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom., Emilson EJS; Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom., Fitch AA; Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom., Osterholz H; Institute for Chemistry and Biology of the Marine Environment and Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, 26129 Oldenburg, Germany., Dittmar T; Institute for Chemistry and Biology of the Marine Environment and Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, 26129 Oldenburg, Germany., Basiliko N; Vale Living with Lakes Centre, Laurentian University, Sudbury, ON P3E2C6, Canada., Mykytczuk NCS; Vale Living with Lakes Centre, Laurentian University, Sudbury, ON P3E2C6, Canada., Tanentzap AJ; Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom. |
| Abstrakt: |
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 terrestrial organic matter (tOM) inputs. Using experimental tOM gradients within sediments of a clear and a dark boreal lake, we identified 156 viral operational taxonomic units (vOTUs), of which 21% strongly increased with abundances of key bacteria and archaea, identified via metagenome-assembled genomes (MAGs). MAGs included the most abundant prokaryotes, which were themselves associated with dissolved organic matter (DOM) composition and greenhouse gas (GHG) concentrations. Increased abundances of virus-like particles were separately associated with reduced bacterial metabolism and with shifts in DOM toward amino sugars, likely released by cell lysis rather than higher molecular mass compounds accumulating from reduced tOM 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 tOM quantity, but not quality, 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. |
