Chapter 10.7. Phylogeographic patterns of the Southern Ocean crinoids
International audience Crinoids are well represented in the Southern Ocean. They locally may con-stitute one of the major mega-epibenthic components and therefore play a crucial role in the functioning of some ecosystems. Because some species are very abundant and well distributed over the whole Sou...
| Main Authors: | , , , |
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| Other Authors: | , , |
| Format: | Book Part |
| Language: | English |
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HAL CCSD
2014
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| Subjects: | |
| Online Access: | https://hal.science/hal-03090444 https://hal.science/hal-03090444/document https://hal.science/hal-03090444/file/Atlas_Chap.10.7-Eleaume_et_al_2014-F.pdf |
| Summary: | International audience Crinoids are well represented in the Southern Ocean. They locally may con-stitute one of the major mega-epibenthic components and therefore play a crucial role in the functioning of some ecosystems. Because some species are very abundant and well distributed over the whole Southern Ocean (Elé-aume 2006; Hemery 2011; Eléaume et al. Chapter 5.25, this volume), they have been recognised as model organisms for studying the spatial variance of genetic diversity in the Southern Ocean.The main hypothesis that explains the patterns of distribution of Antarctic benthic genetic diversity is linked to the cyclical advance of ice sheets on the Antarctic continental shelf. In this hypothesis, the Antarctic shelf ecosystems have undergone cyclical disturbance events during the last 35 My (see review in Turner et al. 2009), including as many as 38 sedimentary cycles of ice sheet advance during the last 5 My (Naish et al. 2009). It is thought that ice advance has regularly eradicated the benthic shelf fauna. Thatje et al. (2005, 2008) suggested that the benthic fauna now flourishing on the shelf arose from ref-uges either in areas left free of ice on the shelf (e.g. polynyas or areas not im-pacted by ice advance), on the adjacent slopes and deep-sea floor, or on the shelves of sub-Antarctic islands. Allcock & Strugnell (2012) summarised the expected molecular patterns for each of these hypotheses. As a result, widely distributed populations were fragmented into smaller populations that have diverged, and sometimes developed barriers to reproduction. This may have been followed by range expansion and, in the case of broadcast spawners, rapid recolonisation of habitats left free of ice, and secondary contact of refu-gial populations. Benthic taxa lacking a dispersal phase are often structured in haplogroups segregated in narrow geographical ranges (Rogers 2007). Clarke & Crame (1992, 2010) proposed that the cyclical nature of the vicari-ance events that may have resulted in genetic divergence and ... |
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