Quantitative data on latest-quaternary benthic foraminiferal assemblages in the South Evoikos Gulf semi-enclosed basin (central Aegean, Greece).

We herein present an original high-resolution dataset on the Late Pleistocene to Holocene (>15.17 ka BP) benthic foraminiferal record of two continuous sediment cores (DEH 5 and DEH 1), drilled from the shallow (max. depth ∼75 m) semi-enclosed basin of South Evoikos Gulf (central Aegean, Greece). Owing to its particular configuration, this marginal setting has been heavily affected by the latest-glacial to modern-interglacial sea-level and climate oscillations that left clear imprints on the benthic foraminiferal community. Our data comprise quantitative information of the downcore faunal distribution (raw species counts and relative abundances), diversity measurements, simplified datasets used for clustering analysis and calibrated age spans. This material can be efficiently utilized in any comparative or synthetic future study on the reconstruction of the latest-Quaternary palaeoceanographic (palaeobathymetric, sea-level) and palaeoenvironmental evolution of the Mediterranean shelf. The present data article is associated with the research article "Impact of latest-glacial to Holocene sea-level oscillations on central Aegean shelf ecosystems: A benthic foraminiferal palaeoenvironmental assessment of South Evoikos Gulf, Greece" by Louvari et al. (2019).

Influence of surface ocean density on planktonic foraminifera calcification.

This study provides evidence that ambient seawater density influences calcification and may account for the observed planktonic foraminifera shell mass increase during glacial times. Volumes of weighed fossil Globigerina bulloides shells were accurately determined using X-ray Computer Tomography and were combined with water density reconstructions from Mg/Ca and δ18O measurements to estimate the buoyancy force exerted on each shell. After assessment of dissolution effects, the resulting relationship between shell mass and buoyancy suggests that heavier shells would need to be precipitated in glacial climates in order for these organisms to remain at their optimum living depth, and counterbalance the increased buoyant force of a denser, glacial ocean. Furthermore, the reanalysis of bibliographic data allowed the determination of a relationship between G. bulloides shell mass and ocean density, which introduces implications of a negative feedback mechanism for the uptake of atmospheric CO2 by the oceans.