Meeting Abstract
Caribbean coral reefs are threatened by disease, and the coral’s microbiome, the complex community of microorganisms on the coral’s surface, plays a critical role in both disease resistance and progression. The microbiome-disease relationship has been inferred solely through relative abundance and functional profiles of bacterial taxa, but here we go beyond these methods, presenting a look at the structure of the microbiome community. Utilizing co-occurrence networks, we measure the microbiome’s connectance, the number of interspecific connections, and its modularity, or groupings of species. A complex microbial community is predicted to be more stable, allowing coral to better resist infection, thus we compare the network topology of the microbiome of two coral genera: Porites, shown to be resistant to white plague disease, and Orbicella, susceptible to white plague. As Porites is resistant, we predicted a more complex, more disturbance-resistant microbiome, than Orbicella’s prior to exposure. We also predicted that disease resistant Porites would not have altered network topology following exposure, whereas the infected Orbicella would have a less connected and more modular microbiome. Prior to disease exposure, we did not find significant differences between the microbiome networks of Porites and Orbicella, rejecting our first hypothesis. After exposure, there is a significant decrease in connectance and increased modularity only in Orbicella, while Porites does not show significant changes in network topology, implying that the ability to maintain a structurally complex microbiome is linked to the ability to resist disease.
