The Eocene-Oligocene transition (between ca. 34 and 33.5 Ma) is the most profound episode of lasting global change to have occurred since the end of the Cretaceous. Diverse geological evidence from around the world indicates cooling, ice growth, sea-level fall, and accelerated extinction at this time. Turnover in the oceanic plankton included the extinction of the foraminifer Family Hantkeninid...

A greater amount of CO2 was stored in the deep sea during glacial periods, likely via greater efficiency of the biologic pump and increased uptake by a more alkaline ocean. Reconstructing past variations in seawater carbonate ion concentration (a major component of alkalinity) enables quantification of the relative roles of different oceanic CO2 storage mechanisms and also places constraints on...

An analytical procedure has been developed for the in situ measurement of calcium isotope composition of carbonates with a spatial resolution of 15–20 μm on a Caméca IMS 1270 ion microprobe. By using two Faraday cup detectors, the Ca and Ca can be measured simultaneously, improving the internal reproducibility. Instrumental mass fractionation (IMF) of calcium isotopes was observed to be indepen...

Planktic foraminifer Globigerinoides ruber (G. ruber), due to its abundance and ubiquity in the tropical/subtropical mixed layer, has been the workhorse of paleoceanographic studies investigating past sea-surface conditions on a range of timescales. Recent geochemical work on the two principal white G. ruber (W) morphotypes, sensu stricto (ss) and sensu lato (sl), has hypothesized differences i...

Growth-independent test characters of the generaOperculina, Planoperculina, andPlanosteginawere investigated to determine relations to water depth in form of morphoclines. All characters describing test form – thickness, initial vector of the test spiral that is correlated to proloculus size, and radius expansion rate describing test contour – are correlated. The investigated Operculina and Pla...