Expedition 378: Planktonic foraminiferal biostratigraphy, biogeography and climatic evolution of the Southern Ocean

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IODP Expedition 378 will drill for the first time in the middle latitude south-west Pacific ocean. Main aim of the expedition is to recover open ocean sediments suitable for paleoceanographic and paleoclimatic reconstructions dating between 55 to 30 million years ago (Eocene to Oligocene Epochs). During this time interval Earth experienced the highest atmospheric carbon dioxide levels of the last 65 million years, and afterwards a gradual cooling which led to the inception of the Antarctic glaciation (34 million years ago) and of a climate state more similar to the modern. By recovering south-west Pacific sediments we will have a close-up view of the long term, Eocene to early Oligocene, climate evolution in this oceanic area which was, at that time, the widest sub-polar region on Earth.The researcher, Dr Flavia Boscolo-Galazzo, will sail on Exp 378 as ship-board biostratigrapher specializing in planktonic foraminifera. Her primary duty on board will be to contribute to preliminary assessments of the age of the recovered sediments by analysing their fossil content, essential to continue the drilling operations. In particular, she will study fossil planktonic foraminiferal species, which are a widely employed tool to define the age of ocean sediments.With the proposed research we aim to refine the age of the sediments provided during the (often hectic) shipboard activity, by analysing a greater number of samples and by performing detailed studies on the morphology (taxonomy) of fossil planktonic foraminifera. This will be essential for any subsequent study aiming at reconstructing the paleoclimate and paleocenography in the drilled region, and to allow comparisons with coeval records from different ocean basins. Further, by analysing a larger number of samples, we will be able to study the influence of climate on planktonic foraminifera evolution through time, and specifically to test whether cooling in this region was accompanied by changes in species composition and in the rate of species origination. This is extremely relevant to assess long term impacts of climate change on marine ecosystems.