Macalester Reviews in Biogeography


Sponge-associated microorganisms are an intriguing system for the consideration of biogeographic patterns due to complications arising from their small size and their symbiotic relationship with sponges. Whether or not microorganisms are capable of exhibiting biogeographic patterns is a topic of heated debate in the literature. Recent studies utilizing new identification techniques have revealed an astonishing amount of diversity and spatiotemporal stability in microorganism communities. Case studies outlined in this paper suggest that some sponge-associated microorganisms represent monophyletic groups that have evolved speciesspecific associations with their hosts. The biogeography of these organisms is receiving increasing attention because they are one of the richest sources of novel bioactive compounds with pharmaceutical applications. Future work in this system should focus on sampling microbial distributions more thoroughly by applying methods with higher phylogenetic resolving power in more diverse habitats.