Holocene ostracod palaeobiogeography of the Seto Inland Sea, Japan: impact of opening of the strait

In this study, published Holocene ostracod data for Osaka, Hiroshima, and lyo-nada Bays within the Seto Inland Sea (SIS), Japan, are re-examined. Five major faunal changes are recognized at different stratigraphic horizons (Horizons 1-5) in the Holocene sedimentary record. Horizons I and 5 (faunal changes) were most likely triggered by the respective openings of the Bisan-seto (and resulting formation of the SIS) and Akashi Straits. Three other major faunal changes, at Horizons 2-4, may also be linked to the opening of straits and resulting formation of bays, although the exact nature of these events is less certain. This re-examination indicates that the opening of straits extensively affected the benthic inner-bay community during the Holocene transgression in the SIS. Further high-resolution studies are needed for confirmation of faunal changes triggered by opening of straits. J. Micropalaeontol. 27(2): 111-116, November 2008.