Kelp genes reveal effects of subantarctic sea ice during the Last Glacial Maximum
Kelp genes reveal effects of subantarctic sea ice during the Last Glacial Maximum
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DOI：
10.1073/pnas.0810635106
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发表时间：
2009-03-03
影响因子：
11.1
通讯作者：
Waters, Jonathan M.
中科院分区：
文献类型：
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作者：
Fraser, Ceridwen I.;Nikula, Raisa;Waters, Jonathan M.
末次盛冰期（LGM）的结束极大地改变了温带生态系统，随着气温上升和冰层消退，许多物种向极地迁移。当陆地生物群重新入侵冰川融化的时候，海洋生物群却重新占据了因海冰融化而腾出的海洋栖息地。然而，末次盛冰期南半球海冰的范围尚未完全确定，大多数古地理研究表明，在亚南极沃茨只有极少量或零星的冰层覆盖。在这里，通过人口遗传学分析广泛的南方牛海带（Durvillaea anacutica），我们提出的证据持续冰冲刷影响subanacuttic岛屿在末次冰期。使用线粒体和叶绿体遗传标记（COI; rbcL）的遗传特征的一些300海带样品从45个南大洋的地方，我们揭示了一个显着的模式，最近的drononization在亚南极洲。具体而言，与新西兰和智利沿海地区（10至100公里尺度）观察到的显著的地理结构相反，亚南极洲样本在很远的距离（10，000公里尺度）上显示出惊人的遗传同质性，每个标记都有一个单一的广泛分布的单倍型。从这些结果中，我们认为，海冰进一步扩大和冰冲刷在末次盛冰期浅水亚南极海洋生态系统的影响比以前提出的更广泛。
The end of the Last Glacial Maximum (LGM) dramatically reshaped temperate ecosystems, with many species moving poleward as temperatures rose and ice receded. Whereas reinvading terrestrial taxa tracked melting glaciers, marine biota recolonized ocean habitats freed by retreating sea ice. The extent of sea ice in the Southern Hemisphere during the LGM has, however, yet to be fully resolved, with most palaeogeographic studies suggesting only minimal or patchy ice cover in subantarctic waters. Here, through population genetic analyses of the widespread Southern Bull Kelp (Durvillaea antarctica), we present evidence for persistent ice scour affecting subantarctic islands during the LGM. Using mitochondrial and chloroplast genetic markers (COI; rbcL) to genetically characterize some 300 kelp samples from 45 Southern Ocean localities, we reveal a remarkable pattern of recent recolonization in the subantarctic. Specifically, in contrast to the marked phylogeographic structure observed across coastal New Zealand and Chile (10-to 100-km scales), subantarctic samples show striking genetic homogeneity over vast distances (10,000-km scales), with a single widespread haplotype observed for each marker. From these results, we suggest that sea ice expanded further and ice scour during the LGM impacted shallow-water subantarctic marine ecosystems more extensively than previously suggested.