We identify the first continuous carbonate-bearing sediment record from the tropical ocean that spans the entirety of the global warming event, the Middle Eocene Climatic Optimum, ca. 40 Ma. We determine significant mismatches between middle Eocene calcareous microfossil datums from the tropical Pacific Ocean and established low-latitude zonation schemes. We highlight the potential of ODP Site 865 for future investigations into environmental and biotic changes throughout the early Paleogene.

Three well-preserved new species of Middle Jurassic (Bajocian) planktonic foraminifera from the continental margin of northwest Australia are described. This is on the southern shelf of the Tethys Ocean, and these planktonics are the first to be reported from the Jurassic Southern Hemisphere. Described as new are Globuligerina bathoniana australiana n. ssp., G. altissapertura n. sp. and Mermaidogerina loopae n. gen. n. sp. The research is part of a study of regional Jurassic foraminifera.

Diatom assemblages in seasonally sea-ice-covered areas of the Sea of Okhotsk, a marginal sea of the western North Pacific, were investigated. We have selected diatom taxa relating to sea-ice coverage by comparing diatom assemblages in sea-ice, sinking-particle, and surface-sediment samples. The results of the study provide fundamental information for the reconstruction of past sea-ice cover based on ice-algal diatoms in sediments in the Sea of Okhotsk and the North Pacific.

To better understand radiolarian evolution and taxonomy, two middle Cambrian specimens recovered from Australia were studied using micro-CT. Analyses of their 3-D models revealed for the first time their skeletal architecture constructed of spicules. Insertion of an artificial sphere into their shells indicates that they may have secreted their spicules one by one during cell enlargement. The timing of skeletal genesis may be an important factor influencing the morphology of early radiolarians.