Bacterial richness in sponges. (a) Phylogenetic distribution of 97% OTUs on phylum (inner circle), class (middle circle) and order level (outer circle). Only taxonomically described phyla and the candidate phylum Poribacteria are shown. Phylum names are given in bold. Selected class and order groups are labeled. *represents unclassified groups. (b) Taxonomic richness of 97% OTUs that were assigned to candidate phyla, for all sponges and for each sponge species. *indicates a sponge-associated unclassified lineage (SAUL). ANZ, Auckland, New Zealand; CAR, Caribbean Sea; GBR, Great Barrier Reef; GUAM, Guam, Pacific Ocean; IND, Indian Ocean; MED, Mediterranean Sea; RS, Red Sea; WNZ, Wellington, New Zealand.