S7.5 Thursday, Jan. 6 Population differentiation in the open sea GOETZE, Erica; University of Hawaii at Manoa firstname.lastname@example.org
Marine zooplankton were long thought to be ‘high gene-flow’ systems with little genetic differentiation among populations, due to large census population sizes and an absence of observable barriers in the open sea. Early genetic studies of oceanic species generally supported this expectation, with observations of high gene flow across 1000s of km of oceanic habitat. A number of recent studies have challenged this view by demonstrating significant genetic structure across a range of spatial scales, and by showing that dispersal capacity may be moderated by species-specific ecological traits. Which ecological traits are primary determinants of dispersal among populations of open ocean species? I will provide an overview of our ongoing research to test the hypothesis that habitat depth specialization is a primary trait driving large-scale population genetic structure of open ocean plankton. This comparative study targets eight species of planktonic copepods that utilize strikingly different depth-related habitats in order to test key predictions about how organismal depth interacts with oceanography and bathymetry to control genetic structure. Early results confirm that zooplanktonic organisms can be genetically subdivided throughout their global range, and seem to suggest greater population subdivision for deeper-dwelling taxa. In particular, results for Pleuromamma xiphias, a deep vertical migrator, demonstrate unexpectedly high levels of genetic differentiation between populations both within and across the Indian, Pacific, and Atlantic Oceans. Finally, I will discuss future research directions in this sub-discipline, and possible innovations in marker development using next generation sequencing strategies.