This study clarified the centennial-scale changes in meiobenthic bay ostracod assemblages in Japan over the past approximately 3000 years with relation to various human-induced and natural environmental factors. These factors were inferred via integrated multiproxy methods of high-resolution geological analyses of core sediments obtained from a shallow bay off a coastal plain, along with literature surveys of archeological and historical records. Five intervals were defined based on multivariate analyses of ostracod assemblages. The ostracod assemblage was stable before around the 6th century because of aggradational sedimentation related to gradual increases in sea level. Since then, the composite factors such as the development of a sandy spit near the study site, stable sea level, regional tectonics, regional centennial-scale climatic change possibly related to El Niño Southern Oscillation (ENSO), and flood mitigation by human settlement in the coastal plains triggered the formation of tidal flats and subtidal sandy areas with seagrass beds. This has markedly influenced offshore bay ostracod assemblages since around the 12th century. Anthropogenic impacts, such as reclamation and various artificial constructions since the late 20th century caused the disappearance of seagrass beds, input of coarser sediment into offshore bays, and increased nutrient loads. Therefore, ostracod assemblages have changed drastically. Ostracod assemblages near the boundary between land and sea have been affected by multiple complex factors, such as regional climate and depositional and human-induced processes during the Late Holocene.

这项研究阐明了在过去的大约3000年中，日本的中底贝类龙骨组合的百年尺度变化与各种人为和自然环境因素有关。这些因素是通过对沿海平原浅湾获得的核心沉积物进行高分辨率地质分析的综合多代理方法以及考古学和历史记录的文献调查得出的。基于对兽类组合的多变量分析，定义了五个间隔。由于与海平面逐渐增加有关的沉积沉积，因此在六世纪之前，兽脚类动物的组合是稳定的。从那时起，研究地点附近的沙嘴的形成，稳定的海平面，区域构造，区域百年尺度的气候变化可能与厄尔尼诺南方涛动（ENSO）有关，人类在沿海平原上定居带来的缓解洪灾引发了潮滩和带海草床的潮下沙质地区的形成。自12世纪左右以来，这已显着影响了近海海湾兽类组合。自20世纪末以来，人为的影响（例如开垦和各种人工建筑）导致海草床的消失，较粗大的沉积物进入近海海湾，并增加了养分负荷。因此，兽脚类动物的组合已发生了巨大变化。陆地和海洋边界附近的鸵鸟组合受到多种复杂因素的影响，例如全新世晚期的区域气候以及沉积和人为过程。