Meeting Abstract
Symbioses between prokaryotes and eukaryotes are ubiquitous in our biosphere, yet we still know little about the role that symbionts play in ecological and ecosystem processes. At deep-sea vents worldwide, dense populations of invertebrates host chemoautotrophic bacterial symbionts that use vent-derived reductants (e.g., H2S) as energy sources for carbon fixation and provide primary nutrition for their host animals. However, despite the predominance of prokaryote-eukaryote symbioses in vent ecosystems, the ecological and biogeochemical effects of symbiont activity are poorly understood. Here, I present evidence that symbiont metabolism plays a substantive role in habitat use by vent symbioses. By pairing a regional-scale survey of vent symbioses in the context of their habitats with analysis of in situ gene expression, we discovered structured habitat partitioning that is consistent with the physiological tendencies of specific symbiont phylotypes. Additionally, experimental manipulations allying assessment of productivity, sulfur metabolism and gene expression demonstrated specific interactions with the environment. Through the metabolic activity of their microbial symbionts, vent symbioses are likely to both influence and be influenced by their abiotic and biotic environment. Thus, symbiont physiology may prove key to understanding the structure of vent communities, as well as local biogeochemical cycles.
