ALBERT

Description: Knowledge about the genetic connectivity of populations is crucial for conserving biological diversity at hydrothermal vents. However, despite the paucity of such data for deep-sea biota, vent communities become increasingly threatened by anthropogenic pressures through resource extraction. Deep-sea mussels of the genus Bathymodiolus are key species in hydrothermal ecosystems worldwide. Using transcriptome sequencing we investigate migration and gene flow patterns among 10 Bathymodiolus populations of the Mid-Atlantic Ridge (37°N to 9°S). We combine outputs of particle tracking analyses using a 1/20° ocean model with genotypic data derived from 103 molecular markers that were designed from high-throughput transcriptomes. Multilocus assignment and differentiation tests indicated the presence of one southern and two northern genetic pools that become increasingly isolated with geographic distance. In spite of the relatively long pelagic duration of Bathymodiolus veligers, our analyses also show that dispersal of more than 100 km is unlikely and that connectivity between known vent populations can only be achieved via intermediate stepping stone habitats. These results have important ramifications for biodiversity conservation in Mid-Atlantic vents that might become targets for mineral extraction activities.