Effects of Late-Cenozoic Glaciation on Habitat Availability in Antarctic Benthic Shrimps (Crustacea: Decapoda: Caridea)

Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany.
PLoS ONE (Impact Factor: 3.23). 09/2012; 7(9):e46283. DOI: 10.1371/journal.pone.0046283
Source: PubMed


Marine invertebrates inhabiting the high Antarctic continental shelves are challenged by disturbance of the seafloor by grounded ice, low but stable water temperatures and variable food availability in response to seasonal sea-ice cover. Though a high diversity of life has successfully adapted to such conditions, it is generally agreed that during the Last Glacial Maximum (LGM) the large-scale cover of the Southern Ocean by multi-annual sea ice and the advance of the continental ice sheets across the shelf faced life with conditions, exceeding those seen today by an order of magnitude. Conditions prevailing at the LGM may have therefore acted as a bottleneck event to both the ecology as well as genetic diversity of today's fauna. Here, we use for the first time specific Species Distribution Models (SDMs) for marine arthropods of the Southern Ocean to assess effects of habitat contraction during the LGM on the three most common benthic caridean shrimp species that exhibit a strong depth zonation on the Antarctic continental shelf. While the shallow-water species Chorismus antarcticus and Notocrangon antarcticus were limited to a drastically reduced habitat during the LGM, the deep-water shrimp Nematocarcinus lanceopes found refuge in the Southern Ocean deep sea. The modeling results are in accordance with genetic diversity patterns available for C. antarcticus and N. lanceopes and support the hypothesis that habitat contraction at the LGM resulted in a loss of genetic diversity in shallow water benthos.

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    • "It is plausible that L. kiae n. sp. is descended from ancestral populations, initially more widely distributed on the Antarctic shelf, which survived in refugia on the seamount systems off the Ross Sea during glacial maxima. Although each of the living Antarctic caridean shrimps has its own specific range of suitable environmental variables (Dambach et al., 2012), habitat-suitability models indicate several periantarctic Islands or seamount systems, such as the Balleny archipelago northwest of the Ross Sea, as potentially suitable habitats for some species. The bottom temperatures of the seamounts off the Ross Sea and the Ross Sea itself are markedly different (i.e., constantly below 0°C on the shelf and above 1°C on the seamounts, Fig. 10), which might represent a barrier to dispersal in the present (Basher et al., 2014). "
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    ABSTRACT: We report a remarkable case of ‘bipolarism’, where two different polar species, namely Lebbeus polaris in the northern hemisphere and Lebbeus kiae n. sp., here described from the Southern Ocean, have been found to share similar ecologies. Despite the great geographical distance between the two species, both show high host fidelity in associations with two congeneric sea anemones: Bolocera tuediae and Bolocera kerguelensis, respectively. A close molecular phylogenetic relationship between the two Lebbeus species is indicated by COI data, which clearly show them as sister clades with respect to other congeners as well as a plurality of other Antarctic species. This is the first reported case of a defensive association in the Southern Ocean involving shrimps and sea anemones. The distribution of the new species, limited to seamount systems off the Ross Sea, may be the result of a specific colonisation/speciation event in the past, although more molecular data are needed to unravel the phylogenetic relationships within the genus Lebbeus. Despite this uncertainty, the persistence of ecological traits, i.e., the defensive association with sea anemones, indicates the presence of niche conservatism in this clade of shrimps.
    Hydrobiologia 07/2015; 761(1). DOI:10.1007/s10750-015-2403-1 · 2.28 Impact Factor
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    • "Previous work using mitochondrial and nuclear sequence data provided clear evidence for a single homogeneous circum-Antarctic N. lanceopes population [4]. These findings were also supported by species distribution modeling data, showing a large connected habitat around the Antarctic continent and the sub-Antarctic islands [5]. Currently, the Antarctic continent faces in some areas dramatic and most rapid effects of climate change, e.g. "
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    ABSTRACT: Background The shrimp Nematocarcinus lanceopes Bate, 1888 is found in the deep sea around Antarctica and sub-Antarctic islands. Previous studies on mitochondrial data and species distribution models provided evidence for a homogenous circum-Antarctic population of N. lanceopes. However, to analyze the fine-scale population genetic structure and to examine influences of abiotic environmental conditions on population composition and genetic diversity, a set of fast evolving nuclear microsatellite markers is required. Findings We report the isolation and characterization of nine polymorphic microsatellite markers from the Antarctic deep-sea shrimp species Nematocarcinus lanceopes (Crustacea: Decapoda: Caridea). Microsatellite markers were screened in 55 individuals from different locations around the Antarctic continent. All markers were polymorphic with 9 to 25 alleles per locus. The observed heterozygosity ranged from 0.545 to 0.927 and the expected heterozygosity from 0.549 to 0.934. Conclusions The reported markers provide a novel tool to study genetic structure and diversity in Nematocarcinus lanceopes populations in the Southern Ocean and monitor effects of ongoing climate change in the region on the populations inhabiting these.
    BMC Research Notes 03/2013; 6(1):75. DOI:10.1186/1756-0500-6-75
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    Bulletin of the Geological Society of Finland; 06/2011
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