Larval dispersal potential of the tubeworm Riftia pachyptila at deep-sea hydrothermal vents

Hydrothermal vents are ephemeral because of frequent volcanic and tectonic activities associated with crust formation(1-3). Although the larvae of hyd rothermal vent fauna can rapidly colonize new vent sites separated by tens to hundreds of kilometres(4,5), the mechanisms by which these larvae disper se and recruit are not understood. Here we integrate physiological, develop mental and hydrodynamic data to estimate the dispersal potential of larvae of the giant tubeworm Riftia pachyptila. At in situ temperatures and pressu res (2 degreesC and 250 atm), we estimate that the metabolic lifespan for a larva of R. pachyptila averages 38 days. In the measured flow regime at a fast-spreading ridge axis (9 degrees 50' N; East Pacific Rise), this lifesp an results in potential along-ridge dispersal distances that rarely exceed 100 km. This limited dispersal results not from the physiological performan ce of the embryos and larvae, but instead from transport limitations impose d by periodic reversals in along-ridge flows and sustained episodes of acro ss-ridge flow. The lifespan presented for these larvae can now be used to p redict dispersal under current regimes at other hydrothermal vent sites.