Deep-sea hydrothermal vents with chemosynthetically-nourished animal communities are patchily distributed along mid-ocean ridges, volcanic arcs and back arcs. Most vent invertebrate animals are benthic as adults and they disperse from the original location to another as pelagic larvae. Larval dispersal therefore plays a significant role in determining the geographic distribution and evolutionary processes of the vent communities. Previous evidence suggests vertical migration of swimming larvae in the water column, but technical obstacles have prevented field observation or tracking trajectories of the microscopic larvae.
The stable isotope and trace element measurements of biogenic carbonates are useful for reconstructing the life history of individual animals. Our geochemical analyses of pre- and post-metamorphic parts of gastropod shells demonstrate for the first time that the plankton-feeding larvae of three limpet species migrate from deep-sea hydrothermal vents (441–1,975 m) to the surface water (0–200 m) as an obligatory part of the species’ life cycle. This result also shows perfect concordance with the larval behavior and temperature optimum observed in culture experiments; they migrate to the surface water to take advantages of high food supply and strong currents for their growth and dispersal. This provides compelling evidence for the influence of surface currents and temperature on the vent communities in the deep sea. These findings will also contribute to developing biophysical models of deep-sea ecosystem connectivity and planning effective marine protected areas.