|Spatiotemporal investigation of population genetic dynamics at deep-sea hydrothermal vents along the East Pacific Rise and Galapagos Rift|
TM Shank, G Gerlach (Riftia pachyptila primer characterization), AR Baco (Riftia pachyptila primer development), DP Adams (Bathymodiolus thermophilus primer development)
Hydrothermal vents are ephemeral and disjunct habitats in which the existence and persistence of their faunal populations depend on the dynamics of vent fluid flow, tectonics, and magmatic events. An archived time-series collection of individuals at multiple vent sites along the East Pacific Rise and Galapagos Rift over the past decade provides the first opportunity for a high resolution genetic investigation of vent population structure, taking into account known disturbances in the vent environment. Larvae, newly-settled colonists, juveniles, and adults from populations of three abundant hydrothermal vent species?the vestimentiferan Riftia pachyptila, the mytilid Bathymodiolus thermophilus, and the commensal polynoid polychaete Branchipolynoe symmytilida?will be analyzed to explore genetic spatiotemporal variability at mid-ocean ridges. These three species exhibit different life-history strategies, proposed to affect their range and population structure. However, larval collection, larval life-span, hydrography, and respiration investigations over the past few decades have led to predictions of dispersal capabilities inconsistent with global and regional distribution patterns and inferred levels of gene flow using traditional population genetic markers. Through the use of new highly polymorphic DNA microsatellite markers, insight into these disagreements will be gained.
Specifically, the research objectives are:
1) To develop and apply DNA microsatellites to a high-resolution investigation of genetic spatiotemporal variability in mussel-tubeworm assemblages in order to correlate genetic structure with colonization and habitat turnover, infer past processes, and predict future state;
2) To apply DNA microsatellites to explain discrepancies in ridge-scale population genetic structure and dispersal potential inferred from larval mode and current dynamics, and to correlate a variety of known/inferred life-history strategies and estimates of gene flow to understand how populations are sustained in an environment prone to multiple scales of disturbance;
3) To gain insight into the existence of vent fauna exhibiting metapopulation dynamics in order to predict the importance of colonization and habitat ephemerality to species maintenance/persistence.
The results of this project will broaden the application of recently-developed molecular techniques to study the effect ridge-crest processes have on vent-endemic species, as well as offer new perspectives into marine dispersal, gene flow, and population differentiation.