Northwestern Pacific biodiversity hotspot: investigating biodiversity and biogeographic patterns and their controlling factors

The Northwestern Pacific Ocean is characterized by the highest biodiversity on Earth. In spite of this obvious importance, our understanding of shallow marine biota in this region is relatively poor compared with well-studied North American and European margins. Here, as a step towards a holistic understanding of northwestern Pacific biodiversity dynamics, we propose to use a microscopic-sized fossil (known as microfossil) group of Ostracoda (small bivalved crustacean) preserved in surface sediments as a model system to investigate detailed present-day shallow-marine biodiversity and biogeographic patterns throughout the northwestern Pacific Ocean as far south as the Indonesian Archipelago and as far north as the Bering Sea and Arctic Ocean. The results will give us a better understanding of large-scale biodiversity and biogeographic patterns in this region. More specifically one of our main goals is elucidating details of latitudinal species diversity gradient, which is one of the most important diversity patterns on Earth characterized by tropical high and polar low diversity. Secondly, we aim to understand biogeographic divisions in the northwestern Pacific Ocean. Thirdly, we plan to investigate the differences of these diversity and biogeographic patterns between taxa, e.g., poor disperser ostracodes vs good dispersers including molluscs. Furthermore, this present-day dataset will enable us to conduct statistical modeling with environmental data to elucidate important factors controlling biodiversity and biogeographic distribution. This detailed investigation of present-day diversity patterns using a taxon with excellent fossil record (i.e., Ostracoda) will help four dimensional (i.e., both spatial and temporal) understanding of large-scale biodiversity dynamics in the future.