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Although larval dispersal and settlement of this species are apparently hydrodynamic
constrained in almost all populations larval retention appeared to be sufficient to
ensure local recruitment, in spite of short larval life span and/or meteorological
conditions. Whereas some populations were mainly self–seeding, larval supply from
neighbouring populations could exceed local retention for other populations
depending on wind forcing.
The flow of water in the deep sea is still not fully understood compared to the
surface circulation. Therefore, in most cases, it is not an easy task to predict where
larvae released at a particular location will go and how long the journey will take.
Marsh et al. (2001) studied the larval dispersal potential of the tube worm Riftia
pachyptila at deep sea hydrothermal vents on the East Pacific Rise. They showed the
prevailing importance of current flow in determining dispersal potential and suggested
that populations at different vent sites may have different dispersal limits depending
on local current conditions. In this region at least, it is apparent that the dispersal
distance of R. pachyptila was not limited by the physiological performance of the
larvae, but by 1) temporal oscillations in the long axis currents and 2) larval loss in
cross-axis flows.
Global termohaline circulation occurs by a variety of pathways that transport
warm waters to high latitudes where they become denser, sink, and finally spread
throughout the oceanic floor (Smethie et al., 2000). One of the most important
pathways by which this process occurs is the formation and spreading of North
Atlantic Deep Water (NADW). The extension of its influence on the deep-ocean
circulation can be measured as the properties of this water mass have been observed
throughout much of the deep ocean and it may extend as far as the North Pacific (Reid
& Lynn, 1971).
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