A review of predators and predation at deep-sea hydrothermal vents

The very few predators at deep-sea hydrothermal vents have been hypothesized to allow extremely vulnerable, relic taxa to survive in these habitats. If vents are viewed as ephemeral habitats in which disturbance is so frequent that few endemic predators can survive, their scarcity, rather than being an anomaly, is seen as a logical consequence of habitat transience. Toxins, however, may minimize exploitation of the habitat by most opportunistic predators. Rates of lethal predation remain undetermined, but vent limpets and vestimentiferans, including those from areas with high sulphide levels, show frequent evidence of non-lethal predation. Characterizing vent habitats as unchanged over geological time and as home to "relic" taxa of ancient groups ignores historic anoxic episodes and the increasing fossil history of vent assemblages. Although trophic relations of vent predators remain poorly known, deep-sea predators are more diverse both taxonomically and in their foraging habits than had been expected; the reportedly vulnerable vent fauna may show unsuspected defenses. Variation in Carbon and Nitrogen isotopes among chemosynthetic taxa and bacteria complicates isotope analyses which are most powerful when supplemented by direct observations and specimen-based documentation of prey. Technological advances offer new promise for these analyses