Assessing the bacterial communities of sponges inhabiting the remote western Indian Ocean island of Mayotte

Abstract

AbstractMarine sponges are known to host diverse and abundant communities of microbial symbionts. It has been generally assumed that the bacterial communities of low microbial abundance (LMA) sponges are less diverse than those of high microbial abundance (HMA) sponges. In this study, we used next‐generation sequencing technology to explore the bacterial communities of several biotopes including sponges, seawater, and sediment from the remote Western Indian Ocean island of Mayotte. The species investigated were the known LMA sponges: Jaspis splendens, Stylissa carteri, and Stylissa massa, and the known HMA sponges: Hyrtios erectus and Xestospongia testudinaria. In addition to this, we also investigated the following sponge species: Ectyoplasia coccinea, Paratetilla bacca, Liosina paradoxa, and Petrosia aff. spheroida of which the exact HMA/LMA status is unknown although we preliminarily classified them as HMA or LMA based on the status of closely related species. Certain HMA sponges shared similar bacterial communities dominated by Actinobacteria and Chloroflexi, whereas another species (E. coccinea) had a bacterial community closer to that of LMA sponges. Most LMA sponges housed a bacteriome dominated by Proteobacteria and Cyanobacteria, but the bacteriome of P. bacca also included dominant Chloroflexi and actinobacterial OTUs. Together with S. carteri, this sponge housed a more diverse bacterial community at the phylum, class, and order levels than HMA sponges. Although certain LMA sponges housed a bacterial community similar to the surrounding environment (seawater), they also included highly abundant, possibly species or genus specific, OTUs. Based on this study and small set of sponges studied, we conclude that a clear dichotomy between HMA and LMA sponges does not appear to exist.