Het Antarctische landijs blijkt veel gevoeliger voor opwarming van oceanen dan eerst werd gedacht, maar hoe veel zeespiegelstijging we kunnen verwachten is onduidelijk, mede door de nu nog onbekende rol die oceanen spelen. Wij gaan die rol van de oceanen in Antarctische ijsvolumeveranderingen onderzoeken tijdens perioden in het verleden met CO2 concentraties vergelijkbaar met die van de nabije toekomst. We passen onze recent ontwikkelde technieken toe op oceaansedimenten om te achterhalen hoe groot de rol van oceanische opwarming was op de variabiliteit van ijskapgrootte. De resultaten hebben directe implicaties voor de projecties van toekomstige zeespiegelstijging.

• dr. Francesca Sangiorgi
• dr. ir. Francien Peterse
• dr. Peter Bijl
• dr. F.S. (Frida) Hoem

Unraveling the stability of the Antarctic cryosphere from its inception during the Greenhouse–Icehouse transition (~34 Ma) through the subsequent periods of climate and atmospheric CO2 changes, is a major current scientific theme. Moreover, Southern Ocean dynamics and phytoplankton productivity is important for global biogeochemical cycling, including the sequestration of carbon dioxide (CO2) and the global carbon balance. The recent (2010) drilling of the Wilkes Land (WL) margin (East Antarctica) now provides an unprecedented long-term record of the Cenozoic East Antarctic climate history. Organic remains of dinoflagellates (dinocysts) are abundant throughout the record, and, importantly, are at times the sole microfossil group preserved. Preliminary analyses indicate that the dinocyst assemblages yield a strong paleoenvironmental signal that is likely strongly dependant from cryosphere dynamics, as (heterotrophic) dinoflagellates record sea-ice cover and oceanic polar fronts. Combined with organic geochemical analyses, and within a multidisciplinary context, the stratigraphic and environmental potential of Antarctic dinoflagellate cyst will serve to document trophic state, sea ice coverage and ocean circulation over critical intervals of the last 34 Ma. This information is crucial to quantify ice sheet dynamics and evaluate the vulnerability of Antarctic ecosystems under changing climate forcing.

• dr. Peter Bijl