Microbiome of the freshwater sponge Ephydatia muelleri shares compositional and functional similarities with marine sponges

We used high-throughput Illumina sequencing of both 16S rRNA gene amplicons and shotgun metagenomes to test three hypotheses about the freshwater sponge Ephydatia muelleri: 1) this species harbors bacterial communities that are distinct from both ambient water and adjacent biofilms; 2) these sponge-associated microbial features are conserved across ecologically similar but geographically isolated sponge populations; and 3) the freshwater sponge microbiome is enriched in many of the same symbiont-associated genetic features that characterize marine sponges.