Monster Seminar JAM - Population Structure and Dispersal of Deep-sea Vent and Seep Organisms: Weedy Species in Ephemeral Environments
Dr. Robert C. Vrijenhoek, Monterey Bay Aquarium Research Institute
Hydrothermal vent communities occur along the global mid-ocean ridge system, in back-arc basins, and on submarine volcanoes. Vent fluids laden with CH4 and H2S sustain chemoautotrophic microbes that serve as primary producers. Cold-water hydrocarbon seeps host similar communities also sustained by chemosynthetic microbes. These island-like habitats are often ephemeral, favoring animals with effective modes of dispersal, rapid growth, and high fecundity; the marine equivalent of terrestrial weeds. Most of the benthic invertebrates that dominate vent and seeps produce free-swimming larvae, capable of dispersing long-distances. Although dispersal can maintain genetic continuity along the length of rift valleys produced by the ridge system, topographic discontinuities (e.g., large transform faults and bathymetric shifts) create barriers that restrict animal dispersal. Such geographical features typically affect multiple species that share similar larval life histories. Yet, the same barriers may not impede the dispersal of other species that arrest larval development or disperse in different oceanic strata. We have used coalescence-based statistical methods to examine mitochondrial and nuclear gene data in attempts to estimate vectors of gene flow in a variety of hydrothermal vent and seep species including mussels, clams, snails and tube-dwelling annelids. Often these studies have led to the identification of genetically discrete, though morphologically cryptic, species.
Date and Time:
January 26, 2006,
11:00 am - 12:30 pm