MCCOY, A.M.; Harvard University: Predicting Biological Invasions: Using Microbes for Highly Specific Predictive Ability

Despite recognition of the potential ecological consequences of biological invasions, factors that determine when a particular invasive will be successful remain largely unknown. Many species in the marine environment rely on specific interactions with microbes for a variety of processes including cues for settlement and morphogenesis, production of bioactive compounds, and nutritional interactions. Specificity in interactions of this type can be a potential barrier to invasion. Just as invaders sometime gain a competitive advantage by �escaping� specific parasites, absence of a beneficial partner imposes a competitive cost upon potential invaders, but that cost disappears if the microbe invades. Unfortunately, the extent of invasions of microorganisms in natural environments remains largely unexplored even though prokaryotic and eukaryotic microbes are the most abundant organisms in ballast water. Characterizing entire microbial communities is difficult and costly, but detecting particular microbes that could act as highly specific predictors for known invasives is tractable once a potentially important microbe has been characterized. The symbiotic acoel Convoluta convoluta is an excellent model system for an investigation into these broad phenomena. C. convoluta has an apparently obligate endosymbiotic diatom it must acquire from the environment with each generation, but has still been a successful invader in the Gulf of Maine and beyond. This association is currently unique in that knowledge of the �symbiont� distribution allows prediction of where the C. convoluta will, and will not invade in subsequent years. With a better understanding of the composition of marine microbial communities we may gain a better ability to predict future invasions.