SGER: Dispersal of Planktonic Invertebrate Larvae and the Biogeography of the Antarctic Benthos

abstractopp99 - 10164 - p。由于早渐新世以来南极洲的极端孤立，人们可以期望遇到一种独特的具有高度地方性的无脊椎动物群。然而，一些底栖动物类群包括20%到50%的非地方性物种。为了解释这些物种，有人提出，在南美洲和南极大陆的反北方种群之间必须发生间歇性的相互交换。维持地理分布和完成遗传交换的一种可能方法是浮游生物幼虫的被动扩散。为了证明这种扩散实际上是完成的，必须证明：(1)在德雷克海峡内确实发现了沿海下物种的幼虫，这些幼虫属于在南美洲和南极的反北动物群中都存在的物种；(2)存在一种水文机制，可以解释幼虫如何在两个大陆之间发生被动运输。拟议的研究将通过对德雷克海峡的浮游生物样本进行横断面取样，并通过检查南极环极流的亚南极和极地锋的幼虫横锋交换的可能性以及中尺度环中幼虫的可能运输来满足这两个要求。这一结果可能表明，将来可以利用分子技术对物种进行有益的研究，比较来自南美洲和南极洲底层种群的个体。这项研究必须是非常初步的，因为以前从未对德雷克海峡中海底底栖生物的浮游幼虫进行过研究。

AbstractOPP99-10164P.I. Rudolf ScheltemaBecause of the extreme isolation of Antarctica since the early Oligocene one can expect to encounter a unique invertebrate fauna with a high degree of endemism. Yet, some benthic taxa include from 20 to 50 percent non-endemic species. To account for such species it has been proposed that an intermittent reciprocal exchange must occur between the antiboreal populations of South America and the Antarctic continent. One possible means by which the geographical distribution can be maintained and genetic exchange may be accomplished is by the passive dispersal of planktonic larvae. To show that such dispersal is actually accomplished it must be demonstrated that (1) larvae of sublittoral species actually are found within the Drake passage and that such larvae belong to species that occur both in the antiboreal South American and Antarctic faunas and (2) that a hydrographic mechanism exists that can explain how the passive transport of larvae may occur between the two continents. The proposed research will address these two requirements by making transects of plankton samples across the Drake passage and by examining the possibility of cross frontal exchange of larvae at the subantarctic and polar fronts of the Antarctic circumpolar current as well as the possible transport of larvae in mesoscale rings. The outcome may suggest species that in the future may profitably be examined using molecular techniques, comparing individuals from bottom populations of South America and Antarctica. The study necessarily must be of a very preliminary nature since the occurrence of planktonic larvae of sublittoral benthic species in the Drake Passage has never before been examined.