0.055 - 0.2 fg carbon/viral particle
||Jover LF, Effler TC, Buchan A, Wilhelm SW, Weitz JS. The elemental composition of virus particles: implications for marine biogeochemical cycles. Nat Rev Microbiol. 2014 Jul12(7):519-28. doi: 10.1038/nrmicro3289. p.519 right column top paragraphPubMed ID24931044
|| Wilhelm, S. W. & Suttle, C. A. Viruses and nutrient cycles in the sea. Bioscience 49, 781–788 (1999). doi: 10.2307/1313569 link  Steward, G. F. et al. Microbial biomass and viral infections of heterotrophic prokaryotes in the subsurface layer of the central Arctic Ocean. Deep-Sea Res. I 54, 1744–1757 (2007). doi:10.1016/j.dsr.2007.04.019 link
||P.519 left column bottom paragraph:"Although previous work did consider the mass of virus particles, the focus was mainly on the carbon content for example, Wilhelm and Suttle [primary source 1] estimated that marine viruses contained 0.2 fg carbon per virus particle, and this estimate has been carried forward in other studies [refs 5,9]. Steward et al. [primary source 10] more recently estimated that marine viruses contained 0.055 fg carbon per virus particle by assuming that viruses are composed of equal parts DNA and protein [ref 11] and leveraging the distributions of lengths of marine virus genomes. Viruses differ in capsid size and structure as well as in genome sequence, and these markedly different estimates of the carbon content of virus particles (0.055–0.2 fg carbon per particle) might reflect the inherent variability across a range of virus types within a community."