Assessing the strength and sensitivity of the core microbiota approach in a diverse sponge assemblage

Marine sponge reefs are usually comprised of a complex array of taxonomically different sponge species, with many of these hosting highly diverse microbial communities. The number of microbial species known to occupy a given sponge ranges from tens to thousands, bringing numerous challenges to their analysis. One way to deal with such complexity is to use a core microbiota approach, which focuses only on those microbes which are consistently associated with the sponge species in question. Here we aimed to test the strength and sensitivity of the core microbiota approach in such systems by applying different core microbiota definitions to a sponge assemblage comprised of 20 species. To minimise sources of additional variation, sampling was conducted in July 2013 at a single location on the south coast of Wellington, New Zealand.