17:15 〜 18:45
[MIS12-P12] トカラ列島における海洋底生生物相の形成機構
キーワード：貝形虫、渡瀬線、生物地理
It is well known that geographical barriers such as straits and mountains hinder the dispersal of organisms. An example of this is the Wataseline, which is established on the Tokara Gap between the Takarajima and Akusekijima islands. Wataseline are generally applied to terrestrial ecosystems. However, some studies have shown that marine biofacies have changed around the Tokara Gap, the possibility remains that effect of geographical barriers on the dispersal of marine ecosystems. In this study, we examined the distribution of marine biofacies using ostracods, a taxon of marine benthic organisms. This study examined the ostracode assemblages in surface sediments collected by GB21-1 and GB21-3 cruise (AIST). This study conducted statistical analyses using the spatial distribution information of modern ostracodes in the adjacent sea of Tokara Islands.
As a result, most ostracods were subtropical and tropical water species reported from the East China Sea, and the Wataseline did not change the ostracod biofacies. Also, a comparison of environmental factors with the ostracod assemblage shows that the ostracods are strongly influenced by water depth and bottom sediment (mud content), and are also affected by transport effects. Some studies have reported that the water mass structure and bottom sediments in the study area are influenced by Kuroshio Current and submarine topography such as submarine volcanoes and ocean basins. These facts show that the distribution of ostracods affects the bottom environment and is strongly influenced by the Kuroshio Current.
Recent studies have reported the dispersal of marine organisms such as shrimp, and luminus ostracods by the Kuroshio Current. In other words, the Kuroshio Current may mean a Wataseline for marine ecosystems.
As a result, most ostracods were subtropical and tropical water species reported from the East China Sea, and the Wataseline did not change the ostracod biofacies. Also, a comparison of environmental factors with the ostracod assemblage shows that the ostracods are strongly influenced by water depth and bottom sediment (mud content), and are also affected by transport effects. Some studies have reported that the water mass structure and bottom sediments in the study area are influenced by Kuroshio Current and submarine topography such as submarine volcanoes and ocean basins. These facts show that the distribution of ostracods affects the bottom environment and is strongly influenced by the Kuroshio Current.
Recent studies have reported the dispersal of marine organisms such as shrimp, and luminus ostracods by the Kuroshio Current. In other words, the Kuroshio Current may mean a Wataseline for marine ecosystems.