Theme 2
Program 2020

Origin and cause of Paleogene hyperthermal events
Program coordinator(s): Dr. G. M. Ganssen
Theme(s): 2
Funding date: 8-apr-05

Earth history is characterized by a number of key periods during which major greenhouse conditions existed. One of these periods mark the Paleocene/Eocene transition (~55 Ma) when a sudden release of methane led to rapid global warming and a period of intense reorganizations in marine (including a notable extinction of about 50% of benthic foraminifera in the deep sea) and terrestrial ecosystems as well as abrupt changes in ocean chemistry, biological pump and atmospheric CO2 concentrations. Recently, a ~2 million year younger distinctive horizon called Elmo was discovered during Ocean Drilling Program Leg 208 (Walvis Ridge) showing similar physical and chemical characteristics as the Paleocene/Eocene transition thereby indicating that massive methane releases during the early Eocene greenhouse world were not exceptional, but probably intrinsic to the climate system. Culture experiments on living calcareous organisms have recently shown that progressive increases in atmospheric CO2 concentrations may slow down the production of calcium carbonate in the surface ocean. Diminished calcification led to a reduction in the ratio of calcite precipitation to organic matter production. This process acts as a negative feedback on atmospheric CO2 levels. To test if similar feedback mechanisms may have played a crucial role during the PETM and Elmo we propose to develop new proxies, validate existing proxies and apply those to a depth transect of cores along the Walvis Ridge in the southern Atlantic Ocean and correlative intervals in other marine locations. Prime targets are 1) the development of methane-related proxies, 2) calibration of the stable carbon isotope ratios and specific mass of coccolithophorids to sea water chemistry and p CO2 changes in culture experiments and 3) reconstruction of sea water temperature, palaeoproductivity and lysocline shoaling across the Elmo event by performing a high resolution study of the sized normalized weight, carbon and oxygen stable isotope composition of individual planktonic and benthic foraminiferal specimens, and the trace metal incorporation in their tests. The ultimate goal of this program is to integrate the biological and chemical aspects of calcareous organisms to develop and apply new tools to unravel the occurrence of extreme greenhouse conditions in the geological past. This knowledge will help to constrain potential feedback mechanisms in the modern ocean-atmosphere system if current greenhouse warming were to be continued into the future.

This program contains the following projects:
2021: Calibration and validation of methane-related proxies
2022: Carbon acquisition in calcareous phytoplankton during major greenhouse events: from biological processes to geological record
2023: Reconstruction of ocean temperature and carbonate chemistry during astronomical-paced early Eocene hyperthermal events

Stoll, H.M., Shimizu, N., Archer, D., Ziveri, P. (2007). Coccolithophore Productivity Response to Greenhouse Event of the Paleocene-Eocene Thermal Maximum. Earth and Planetary Science Letters258: 192-206.

Langer, G., Nehrke, G., Probert, I., Ly, J., Ziveri, P. (2009). Strain-specific responses of Emiliania huxleyi to changing seawater carbonate chemistry. BIOGEOSCIENCES6: 2637-2646.

Stap, H.L., Sluijs, A., Thomas, E., Lourens, L.J. (2009). Patterns and magnitude of deep sea carbonate dissolution during Eocene Thermal Maximum 2 and H2, Walvis Ridge, southeastern Atlantic Ocean . Paleoceanography24: 1-13.
Darwin Center authors: Lourens L. J., Sluijs A., Stap L.

Stap, H.L., Lourens, L.J., Thomas, E., Sluijs, A., Bohaty, S., Zachos, J.C. (2010). High-resolution deep-sea carbon and oxygen isotope records of Eocene Thermal Maximum 2 and H2. Geology38: 607- 610.
Darwin Center authors: Lourens L. J., Sluijs A., Stap L.

Lucy Stap (2010). Palaeoceanographic and biotic response during early Eocene extreme global warming events.
Darwin Center authors: Stap L.

Stap, H.L., Lourens, L.J., Van Dijk, A., Schouten, S., Thomas, E. (2010). Coherent pattern and timing of the carbon isotope excursion and warming during Eocene Thermal Maximum 2 as recorded in planktic and benthic foraminifera. Geochem. Geophys. Geosyst.11, Q11011:
Darwin Center authors: Lourens L. J., Schouten S., Stap L.

NĂ­ Fhlaithearta, S., G.-J. Reichart, F. J. Jorissen, C. Fontanier, E. J. Rohling, J. Thomson, and G. J. De Lange (2010). Reconstructing the seafloor environment during sapropel formation using benthic foraminiferal trace metals, stable isotopes, and sediment composition. Paleoceanography25:
Darwin Center authors: de Lange G. J., Ni Fhlaithearta S., Reichart G. J.

Dedert, M., Stoll, H.M. , Kroon, D., Shimizu, N., Ziveri, P. (2011). Productivity response of calcareous nannoplankton in the South Atlantic to the Eocene Thermal Maximum 2 (ETM2) . Climate of the Past DiscussionsVolume 7, Issue 3: 2089-2118.
Darwin Center authors: Dedert M.

Mascha Dedert (2012). The calcareous nannoplankton response to hyperthermals reconstructed from late Palaeocene and Early Eocene deep-sea sediments.
Darwin Center authors: Dedert M.