Resilience and connectivity of hydrothermal vent polychaetes and endosymbionts in the northeastern Pacific Ocean.
The machinery for mineral exploitation of hydrothermal vents is already operational and the issuing of mining permits is imminent despite a concerning knowledge deficit about these ecosystems 1. Particularly, too little is known about the physiological response of vent species to changing environmental conditions and about interconnectivity (gene flow) between vents to predict whether a vent community can survive or be restored on a disturbed site. In the northeastern Pacific Ocean, these communities are characterized by dense populations of the foundation species Ridgeia piscesae 2. These tubeworms (Polychaete: Annelida) lack a digestive system and rely on intracellular chemosynthetic bacteria for their nutrition. Surprisingly, they are found across environments varying considerably in terms of temperature, oxygen, and mineral concentration, which are associated with a great degree of phenotypic plasticity. Because of their wide distribution, important ecological role, and diverse morphotypes coupled to thermal regimes, R.piscesae worms are a good model to study resilience and connectivity at hydrothermal vents 2. The objectives of my thesis are to (1) understand how the worms tolerate such wide range of environmental conditions, and (2) compare the connectivity between host and symbiont populations. Ultimately, this project aims to identify general mechanisms of physiological adaptation and patterns of colonization at the northeastern Pacific vents in order to provide conservation guidelines for the upcoming marine operations.