Data from: Response of subtropical submarine-cave ecosystem to Holocene cave development and Asian monsoon variability

A submarine cave is a unique environment, which is dark, food-limited, semi-isolated from the outside, and sheltered from wave actions. However, our knowledge on the long-term change in submarine cave ecosystem remains limited. Here we document the community-scale responses towards long-term change in a submarine cave, Daidokutsu, in Okinawa, southern part of Japan. Using both metazoans (ostracods and bivalves) and protozoans (larger benthic foraminiferans) in two sediment cores obtained from the cave, the past 7000-year faunal and diversity changes are reconstructed. All taxonomic groups showed long-term, gradual linear change of the faunal composition from more open-water taxa dominant one to more cave taxa dominant one, and ostracods showed short-term variability of species diversity. The long-term faunal trend probably reflects gradual isolation of the cave and its ecosystem due to coral reef development (i.e., development of the cave ceiling) during the periods of the Holocene transgression and subsequent sea-level highstand. The short-term diversity changes show substantial similarity to centennial–millennial scale Holocene Asian monsoon variability. Ostracod species diversity peaks tend to correspond to the periods of strong East Asian winter monsoon. The results indicate that limestone submarine cave ecosystem, an important cryptic habitat, has been gradually developed during the Holocene and may be sensitive to rapid climate changes.