10^6-10^8 viral particles/ml
||Taylor MW, Radax R, Steger D, Wagner M. Sponge-associated microorganisms: evolution, ecology, and biotechnological potential. Microbiol Mol Biol Rev. 2007 Jun71(2):295-347. DOI: 10.1128/MMBR.00040-06 p.325 left column 2nd paragraphPubMed ID17554047
|| Suttle CA (2005) Viruses in the sea. Nature 437(7057):356–361. DOI: 10.1038/nature04160PubMed ID16163346
||P.325 left column 2nd paragraph: "Interestingly, it now appears that even viruses can be retained by sponges, with some 23% of viral particles being removed from seawater by the Red Sea sponge Negombata magnifica (BNID 113290). Considering the enormous abundance of viruses in seawater (1 million to 100 million per ml) (primary source), this could represent a significant flux of nutrients in ecosystems containing large sponge populations."