OceaNice addressed the role ocean conditions around Antarctica had on past fluctuations in size of the Antarctic ice sheet. It focused on key past warm time intervals: The Pleistocene (1-0 Myr), the Pliocene (3.5-3 Myrs ago) and the mid-Miocene (17-14 Myrs ago). Oceanice groundtruthed the use of organic-walled dinoflagellate cyst assemblages to reconstruct past paleoenvironmental conditions: sea ice, sea surface temperature and nutrients/upwelling by augmenting surface sediment sample datasets and developing transfer functions to translate fossil dinocyst assemblages to past surface ocean conditions in an accurate, quantitative way. It then applies these tools together with biomarker proxies for SST to Pleistocene glacial-interglacial fluctuations, notably to investigate the latitudinal migration of ocean frontal systems. It further applies these proxies to Pliocene and Miocene sedimentary records, to investigate past surface ocean conditions. In conclusion, OceaNice met its main aim to develop and test the use of fossil dinoflagellate cysts for reconstruction of past ocean surface temperature, nutrients, sea ice and salinity conditions, even in a quantitative way. We have used these tools to provide a long-term history of the latitudinal position of ocean fronts throughout the Neogene, and this provides the much-needed context of ocean structure that can be tied to reconstructed dynamics of the Antarctic ice sheet. In doing so, we collaborated with ice sheet modelers who could demonstrate that the Miocene might not have had such strong increase in ice volume, but a change in geometry, whereby the icesheets reduced in height but extended in surface area, thereby advancing towards the coast. The project further targeted high-resolution reconstructions of ocean change in the Pleistocene and Pliocene, with some unexpected results: the magnitude of northward migration of fronts in the Indian Ocean during Pleistocene glacial maxima, and during glacial-interglacial transition prior to the mid-Piacenzian warm period. The most recent result from OceaNice targeted a surprising geologic question of the find of iceberg-rafted debris offshore an island in the Scotia Sea, in the Late Eocene, 3 million years prior to the onset of Antarctic glaciation. We demonstrate with particle trace experiments in a late Eocene ocean model that this island was in the middle of the track of icebergs out of the WEddell Sea, and that that ocean was cold enough to have mid-sized icebergs survive the ocean track to the island. This demonstrates the likelyhood that Late Eocene Antarctica was indeed already glaciated with marine terminated tongues that generated ice bergs, and puts Late Eocene Climate as well as the onset of Antarctic glaciation into a new perspective. Quite a bit of research results are still in the pipeline, expanding on the application of the new dinocyst-based proxy for ocean conditions.
