Studies of taxonomy, phylogeny and peculiar evolution of marine organisms inhabiting marine lakes from the viewpoint of vacarism

在帕劳群岛，大约有80个海洋湖泊分布在洛基岛区周围。这些湖泊与公海隔绝，为海洋生物系统提供了封闭的海洋生态系统。在地质上和基因上，几乎所有的生物都与居住在公海上的生物隔绝，至少在一万年前，当海洋湖泊在最后一次冰期后形成时。它们表现出独特的大体形态，因此可以假设它们在自己的进化过程中漂移。在我们对帕劳进行的七次考察中，我们进入了19个海洋湖泊。在湖泊学意义上，这些湖泊可分为完整湖泊和分生湖泊两种。在海洋湖泊中，海藻的种类组成相似，优势种共有，这取决于这些海洋湖泊类型。这是本项目的中心，旨在根据形态学和分子系统发育的分析，对海洋湖泊中优势或具有代表性的海藻和其他动物类群的独特进化证据进行研究。在湖底沉积物的基础上，尝试用放射性同位素和微古生物学方法估算海洋湖泊的年龄。不幸的是，我们无法从我们访问的所有海洋湖泊中收集到适合这些分析的样本。因此，我们必须考虑到帕劳海洋湖泊的标准年龄大约比以前认为的要早一万年。在此基础上，通过分子系统发育分析的验证，建立了基于外部形态和内部结构的海洋湖泊海藻识别体系。利用该系统，可以比较海洋湖泊内外、湖泊间和湖泊内海藻的遗传差异。目前，我们还没有明确的证据表明海洋生物系统在海洋湖泊中发生了特殊的进化，但利用线粒体基因组可以在动物标本上展示这种可能性。而在18SrDNA、rbcL和ITS区域水平上，海藻的特殊进化大多被忽视。在引入具有更快进化速度的分子或具有更密切的系统发育关系的其他方法之后，将需要进一步的研究。少

In Palau Archipelago, about 80 marine lakes are located around Rocky Island District. These lakes are isolated from open sea and provide closed marine ecosystem to oceanic life systems. Almost all are geologically and genetically isolated from those inhabiting open seas, at least ten thousand years ago when the marine lakes were formed after he last glacial age. They show unique gross morphology, therefore it can be supposed that they have drifted on their own evolutionary processes. During our seven expeditions to Palau, 19 marine lakes have been accessed. On the limnological sense, these are divided into two of the holomictic and meromictic lakes. In the case of seaweeds in marine lakes, the similar species compositons and common dominant species share depending on these types of marine lakes. This is the center of this project for taking the evidences of their peculiar evolution of dominant or represenntative seaweeds and other groups of animal assembrages in the marine lakes based … More on the analyses of morphology and molecular phylogeny. The estimation of marine lakes' ages has been tried using the radio isotope and micropaleontological methods on the basis of sediments deposited in the bottom of lakes. Unfortunately, the suitable samples for these analyses could not be collected from all marine lakes we accessed. Consequently, we have to consider that the standard age of marine lakes in Palau is approxmately ten thoughsand years previously thought.From the results obtained here, the identification system of seaweeds in marine lakes based on their external morphology and internal strucutres was established with the verification of the molecular phylogenetic analysis. Owing to use this system, we could compare the genetic divergences of seaweeds inside and outside, as well as inter and intra marine lakes. At present, we could not show the clear evidences to occur the peculiar evolution of marine life systems in marine lakes, however, the possibilities could be exhibit on animal assebrages using mitochondrial genomes. While the peculiar evolution of seaweeds was mostly neglected at 18SrDNA, rbcL and ITS region levels. Further investigations will be needed after introducing molecules with much more rapid evolutionary speed or another methods possessing the resolving power to much more closely phylogenetic relationships. Less