~10^6 cells/cm^2 of coral tissue
||Blackall LL, Wilson B, van Oppen MJ. Coral-the world's most diverse symbiotic ecosystem. Mol Ecol. 2015 Nov24(21):5330-47. doi: 10.1111/mec.13400 p.5334 right column 3rd paragraphPubMed ID26414414
||Kawaguti S, Nakayama T (1973) Population densities of zooxanthellae in reef corals. Biological Journal of Okayama University, 16, 67–71
||P.5334 right column 3rd paragraph: "In hospite Symbiodinium populations are maintained by binary fission and cell densities are large, that is, in the order of 10^6 cells/cm^2 of coral tissue (primary source)."