The spatial scale of genetic subdivision in populations of Ifremeria nautilei, a hydrothermal-vent gastropod from the southwest Pacific

Andrew D Thaler,Jens Carlsson,Thomas F Schultz,Clifford Cunningham,Robert C Vrijenhoek,Kevin Zelnio,Cindy L Van Dover,William Saleu

doi:10.1186/1471-2148-11-372

Abstract

BackgroundDeep-sea hydrothermal vents provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production. Unlike eastern Pacific hydrothermal vents, where population structure has been studied at large (thousands of kilometres) and small (hundreds of meters) spatial scales, population structure of western Pacific vents has received limited attention. This study addresses the scale at which genetic differentiation occurs among populations of a western Pacific vent-restricted gastropod, Ifremeria nautilei.ResultsWe used mitochondrial and DNA microsatellite markers to infer patterns of gene flow and population subdivision. A nested sampling strategy was employed to compare genetic diversity in discrete patches of Ifremeria nautilei separated by a few meters within a single vent field to distances as great as several thousand kilometres between back-arc basins that encompass the known range of the species. No genetic subdivisions were detected among patches, mounds, or sites within Manus Basin. Although I. nautilei from Lau and North Fiji Basins (~1000 km apart) also exhibited no evidence for genetic subdivision, these populations were genetically distinct from the Manus Basin population.ConclusionsAn unknown process that restricts contemporary gene flow isolates the Manus Basin population of Ifremeria nautilei from widespread populations that occupy the North Fiji and Lau Basins. A robust understanding of the genetic structure of hydrothermal vent populations at multiple spatial scales defines natural conservation units and can help minimize loss of genetic diversity in situations where human activities are proposed and managed.

Highlights

Deep-sea hydrothermal vents provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production
We examined genetic population structure of Ifremeria nautilei from hydrothermal vents in Manus, North Fiji, and Lau Basins at multiple scales, ranging from meters to thousands of kilometres (Figure 1)
Thirty-six partial COI haplotypes (404 bp) were identified from 158 Ifremeria nautilei sampled from Manus Basin; an additional 25 haplotypes were identified from 117 individuals from North Fiji and Lau Basins

Summary

Introduction

Deep-sea hydrothermal vents provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production. Unlike eastern Pacific hydrothermal vents, where population structure has been studied at large (thousands of kilometres) and small (hundreds of meters) spatial scales, population structure of western Pacific vents has received limited attention. The spatial scales at which individuals within a population interact and the geographic extent of larval dispersal shape the dynamics of marine populations. Larval development can impose limits on dispersal Species that brood their offspring (direct development) tend to have more restricted distributions than species with long-lived, planktonic larvae [3], though exceptions exist [4]. Species that aggregate in small patches may interact and reproduce with other individuals in an area encompassing a meter or less [5] and larvae that lack broad dispersal potential may recruit to their natal population [6]. A sampling scheme that fails to account for the localized effects of self-recruiting patches may create an appearance of panmixia, even if substructure exists among patches [7]

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