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<p>Genetic diversity, population structure, and connectivity influence interactions
among communities and populations. At hydrothermal vents in the western pacific, population
structure in vent-associated species could occur at spatial scales ranging from vent
sites separated by a few hundred meters to oceanic basins separated by more than 3000
kilometers. The spatial scale of population structure has important conservation implications;
species that are well-connected across large geographic regions are more resilient
to natural and anthropogenic disturbance. This dissertation examines the genetic
diversity, population structure, and connectivity of 3 vent-associated species in
the western Pacific. It first presents results from the development of microsatellite
primers for Ifremeria nautilei, a deep-sea vent associated snail, then uses mitochondrial
COI sequences and a suite of microsatellite markers to examine the broader connectivity
of three vent-associated species, Ifremeria nautilei, Chorocaris sp. 2, and Olgasolaris
tollmanni, across three back-arc basins in the western Pacific. </p><p>Within Manus
Basin, no significant genetic differentiation was detected in populations of Ifremeria
nautilei (based on COI and microsatellite), Chorocaris sp. 2 (based on COI and microsatellite),
or Olgasolaris tollmanni (based on COI). A previously documented low-abundance cryptic
species, Chorocaris sp. 1, was detected from a single site, South Su (based on COI).
The population of I. nautilei in Manus Basin was found to be significantly differentiated
from a second population that appeared to be panmictic across North Fiji and Lau Basin
(based on COI and microsatellites). Chorocaris sp. 2 was also found to be significantly
differentiated between Manus and North Fiji Basin (based on COI). Both I. nautilei
and Chorocaris sp. 2 showed signs of potential low-level migration between Manus and
other southwestern Pacific basins. O. tollmanni was undifferentiated between Manus
and Lau Basin (based on COI). It is likely that a variable impedance filter exists
that limits the realized dispersal of some, but not all species between Manus Basin
and other western Pacific back-arc basins. The presence of a variable filter has implications
for the conservation and management of hydrothermal vents in Manus Basin, as it is
unclear what effects sustained anthropogenic disturbance will have on isolated populations
of I. nautilei and Chorocaris sp. 2.</p>
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