What we know, what we can know, and what we will never know about the larval dispersal process at deep-sea chemosynthetic ecosystems

The discovery of unfathomably high animal biomass inhabiting deep seafloors with geofluid input, such as hydrothermal vents, is widely recognized as one of the most extraordinary scientific achievements in recent history. Four decades since its discovery, how animals migrate between these stepping stone-like habitats remains a fascinating research topic. The concept of larval dispersal where animals migrate during their early life stages (as eggs or larvae), is generally accepted as the only viable process for this to occur. Here, we review existing studies concerning this process in three stages (emigration, migration, and colonization) and consider two different viewpoints (biological factors and seawater dynamics). Furthermore, we disentangle the obstacles and limitations related to the study of animal dispersal in hydrothermal vents, discuss new developments in the field, and provide an outlook on research in the coming decades.