Deep-sea anemone associated microbiome

A new chemosynthetic symbiosis between the sea anemone Ostiactis pearseae and intracellular bacteria was discovered at ~3700 m deep hydrothermal vents in the southern Pescadero Basin, Gulf of California. Unlike most sea anemones observed from chemically-reduced habitats, this species was observed in and amongst vigorously venting fluids, side-by-side with the chemosynthetic tubeworms. Despite success in nearly all marine habitats and their well-known associations with photosynthetic symbionts, Cnidaria remain one of the only phyla without a clear dependence on hydrothermal vents and reliance on chemosynthetic bacterial symbionts specifically. Ostiactis pearseae maintains a physical and nutritional alliance with chemosynthetic bacteria. The mixotrophic nature of this symbiosis is consistent with the dynamic relationships formed by both the SUP05 bacterial group and Anthozoa. The advantages gained by appropriating metabolic and structural resources from each other presumably contribute to their striking abundance in the Pescadero Basin, at the deepest known hydrothermal vents in the Pacific Ocean.