biostudies-literatureUnknown24(1)Kaneko HJapan Society for the Promotion of ScienceThe biological carbon pump, in which carbon fixed by photosynthesis is exported to the deep ocean through sinking, is a major process in Earth's carbon cycle. The proportion of primary production that is exported is termed the carbon export efficiency (CEE). Based on in-lab or regional scale observations, viruses were previously suggested to affect the CEE (i.e., viral "shunt" and "shuttle"). In this study, we tested associations between viral community composition and CEE measured at a global scale. A regression model based on relative abundance of viral marker genes explained 67% of the variation in CEE. Viruses with high importance in the model were predicted to infect ecologically important hosts. These results are consistent with the view that the viral shunt and shuttle functions at iScience102002https://www.ebi.ac.uk/biostudies/studies/S-EPMC7811142biostudies-literatureEukaryotic virus composition can predict the efficiency of carbon export in the global ocean.PMC7811142Blanc-Mathieu ROgata HHernandez-Velazquez REndo HMamitsuka HGaia MKaneko HChaffron SForterre Pde Vargas CGuidi LNguyen CHJaillon OHenry NDelmont TOSuttle CASullivan MBfalseEukaryotic virus composition can predict the efficiency of carbon export in the global ocean.The biological carbon pump, in which carbon fixed by photosynthesis is exported to the deep ocean through sinking, is a major process in Earth's carbon cycle. The proportion of primary production that is exported is termed the carbon export efficiency (CEE). Based on in-lab or regional scale observations, viruses were previously suggested to affect the CEE (i.e., viral "shunt" and "shuttle"). In this study, we tested associations between viral community composition and CEE measured at a global scale. A regression model based on relative abundance of viral marker genes explained 67% of the variation in CEE. Viruses with high importance in the model were predicted to infect ecologically important hosts. These results are consistent with the view that the viral shunt and shuttle functions at 2021-01-01T00:00:00Z2021 Jan2025-04-25T17:45:51.907Z2025-04-25T17:45:51.907ZS-EPMC78111423349091010.1016/j.isci.2020.102002