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.

Cutting through the smoke: the diversity of microorganisms in deep-sea hydrothermal plumes

“…However, these two sites are also distinct from each other (PERMANOVA, p <0.01), likely because of differences in the environment. Future research should investigate the global biogeography of free-living microorganisms around hydrothermal vents comparing the microbial biogeography to that of metazoan vent communities [8,69,71,72]. It has been postulated that certain microorganisms might disperse with macroorganisms, thus, including microorganisms into these biogeographic regions might be more meaningful as a measure of habitat construct (i.e.…”

Exploring the Ecology of Deep-Sea Hydrothermal Vents in a Metacommunity Framework

“…Bayesian assignment approaches have also recently been utilized to infer population migration rates in alvinocaridid shrimp along the MAR (Teixeira et al, 2012) and western Pacific backarc basins (Thaler et al, 2014), alvinellid polychaetes from the eastern Pacific ridges (Jang et al, 2016), bathymodiolin mussels from the Indo-Pacific (Breusing et al, 2015) and the MAR (Breusing et al, 2016), and lepetodrilid limpets from the Scotia Sea (Roterman et al, 2016). Migration rate estimates are most accurate and precise when true migration rates among populations are moderate (m < 0.333), population structuring is significant, and sampling of individuals and loci is substantial (Faubet et al, 2007;Meirmans, 2014).…”

Hydrological features above a Southern Ocean seamount inhibit larval dispersal and promote speciation: evidence from the bathyal mytilid Dacrydium alleni sp. nov. (Mytilidae: Bivalvia)

“…This is the most common method of reproduction in Antarctic bivalves (Brandt et al 2011) and typical of the genus (Salas and Gofas 1997). Long-range transport of lecithotrophic larvae has been previously documented in the Antarctic, enabled in part by the decreased metabolic demands in cold Antarctic waters (Roterman et al 2016). Although dispersal via currents of D. alleni sp.…”