title: Connectivity in the cold: the comparative population genetics of vent-endemic fauna in the Scotia Sea, Southern Ocean.
abstract: We report the first comparative population genetics study for vent fauna in the Southern Ocean using cytochrome C oxidase I and microsatellite markers. Three species are examined: the kiwaid squat lobster, Kiwa tyleri, the peltospirid gastropod, Gigantopelta chessoia, and a lepetodrilid limpet, Lepetodrilus sp., collected from vent fields 440 km apart on the East Scotia Ridge (ESR) and from the Kemp Caldera on the South Sandwich Island Arc, ~95 km eastwards. We report no differentiation for all species across the ESR, consistent with panmixia or recent range expansions. A lack of differentiation is notable for Kiwa tyleri, which exhibits extremely abbreviated lecithotrophic larval development, suggestive of a very limited dispersal range. Larval lifespans may, however, be extended by low temperature-induced metabolic rate reduction in the Southern Ocean, muting the impact of dispersal strategy on patterns of population structure. COI diversity patterns suggest all species experienced demographic bottlenecks or selective sweeps in the past million years and possibly at different times. ESR and Kemp limpets are divergent, although with evidence of very recent ESR-Kemp immigration. Their divergence, possibility indicative of incipient speciation, along with the absence of the other two species at Kemp, may be the consequence of differing dispersal capabilities across a ~1000 m depth range and/or different selective regimes between the two areas. Estimates of historic and recent limpet gene flow between the ESR and Kemp are consistent with predominantly easterly currents and potentially therefore, cross-axis currents on the ESR, with biogeographic implications for the region.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
authors.forename: C N
authors.initials: CN
authors.lastname: Roterman
authors.affiliation: Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton, SO14 3ZH, UK.
authors.forename: J T
authors.initials: JT
authors.lastname: Copley
authors.affiliation: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK.
authors.forename: K T
authors.initials: KT
authors.lastname: Linse
authors.affiliation: Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton, SO14 3ZH, UK.
authors.forename: P A
authors.initials: PA
authors.lastname: Tyler
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
authors.forename: A D
authors.initials: AD
authors.lastname: Rogers
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D003080:Cold Temperature; D033364:Decapoda / Q000235:genetics*; D017753:Ecosystem; D003576:Electron Transport Complex IV / Q000235:genetics; D049851:Gastropoda / Q000235:genetics*; D051456:Gene Flow; D005828:Genetics, Population; D005838:Genotype; D060086:Hydrothermal Vents; D018895:Microsatellite Repeats; D009792:Oceans and Seas; D011157:Population Dynamics; D017422:Sequence Analysis, DNA
chemical_list: D003576:Electron Transport Complex IV
keywords: Gigantopelta; Kiwa; Lepetodrilus; Southern Ocean; connectivity; hydrothermal vents