Spatial and temporal population genetics at deep-sea hydrothermal vents along the East Pacific Rise and Galápagos Rift
Citable URI
https://hdl.handle.net/1912/2564Location
East Pacific RiseGalapagos Rift
DOI
10.1575/1912/2564Keyword
Hydrothermal vent ecology; Tube worms; Atlantis (Ship : 1996-) Cruise AT7-06; Atlantis (Ship : 1996-) Cruise AT11-01; Atlantis (Ship : 1996-) Cruise AT7-13; Atlantis (Ship : 1996-) Cruise AT11-27; Atlantis (Ship : 1996-) Cruise AT3-50; Atlantis (Ship : 1996-) Cruise AT3-51Abstract
Ecological processes at deep-sea hydrothermal vents on fast-spreading mid-ocean ridges
are punctuated by frequent physical disturbance. Larval dispersal among disjunct vent
sites facilitates the persistence of sessile invertebrate species in these geologically and
chemically dynamic habitats despite local extinction events. Regional population
extension and rapid recolonization by the siboglinid tubeworm Riftia pachyptila have
been well documented along the East Pacific Rise and the Galápagos Rift. To analyze
spatial and temporal population genetic patterns and the processes governing them at
ephemeral and disjunct habitats, a suite of 12 highly variable microsatellite DNA markers
were developed for this species. Eight of these loci were used to assess the regional and
within-ridge genetic structure of recent colonists and resident adults collected from nine
sites in the eastern Pacific Ocean over period of three to seven years. A significant
seafloor eruption during the seven-year sampling period allowed investigation into the
role of local extinction in population genetic diversity at the Tica vent site at 9°N EPR,
while collections within two and five years of an eruption that created the Rosebud vent
field at 86°W GAR provided insights into genetic diversity input over population
establishment.
For the first time, this thesis demonstrated significant genetic differences between Riftia
populations on the East Pacific Rise and Galápagos Rift. Moreover, the separate
treatment of colonist and resident subpopulations revealed a high potential for local larval
retention at vent sites. This mechanism for recruitment likely sustains disjunct
populations and supports the recolonization of locally extinct areas after disturbance
events, while episodic long-distance dispersal maintains genetic coherence of the species.
Temporal population genetic consideration at the Tica site on the East Pacific Rise
suggests that the 2005-2006 seafloor eruption had little to no discernable effect on local
population genetic composition. Yet local populations appear to exhibit a small degree of
genetic patchiness, with a high degree of relatedness (half-sibs) among subsets of
individuals within both colonist and resident cohorts. This thesis broadens the application
of recently developed molecular techniques to study the effect of ridge-crest processes
and offers new perspectives into marine dispersal, gene flow, and population
differentiation.
Description
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2008
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Suggested Citation
Thesis: Fusaro, Abigail Jean, "Spatial and temporal population genetics at deep-sea hydrothermal vents along the East Pacific Rise and Galápagos Rift", 2008-09, DOI:10.1575/1912/2564, https://hdl.handle.net/1912/2564Related items
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