Postdoctoral Researcher in Marine Biology / Biogeosciences (1.0 FTE)

The Department of Earth Sciences currently seeks a highly-motivated, high-potential applicant for a position as a Postdoctoral Researcher to work within the research project 'Validation and calibration of a novel dinoflagellate-based proxy for atmospheric CO2 concentrations'.

Forecasting the magnitude of future global warming is among the grand scientific challenges. Model estimates of long-term warming resulting from a doubling of the CO2 concentration relative to the pre-industrial era range between 1.5 and 4.5 °C (IPCC, 2013). Within a Consolidator Project funded by the European Research Council termed SPANC, this Equilibrium Climate Sensitivity (ECS) factor will be investigated through accurate reconstructions of past climate change. To this end, past CO2 concentrations will be reconstructed using a novel proxy based on dinoflagellates and their fossil cysts, specifically their CO2-dependent carbon isotope fractionation.

Culturing experiments have shown a clear relation between ambient CO2 concentrations and dinoflagellate ?13C (Rost et al., 2006; Hoins et al., 2015; Hoins et al., 2016; Wilkes et al., 2017), including species with long fossil records such as Protoceratium reticulatum and Gonyaulax spinifera (Hoins et al., 2015). Ongoing efforts at Utrecht University assess the effect of seawater chemistry on dinocyst ?13C by modern field studies, using sediment traps, surface sediments and Pleistocene ice ages to calibrate the proxy in the field. In this project, two unknowns will be investigated: 1) the effect of seawater temperature on dinoflagellate 13C fractionation, and 2) the relation between motile dinoflagellate ?13C and their cysts, particularly at higher-than-Pleistocene CO2 concentrations.

To quantify the relation between seawater temperature and 13C fractionation, the successful candidate will design and perform multiple stressor dilute batch experiments with different combinations of temperature and CO2 concentrations. Quantifications of the relation between motile dinoflagellates and their cysts will encompass cyst formation experiments using multiple strains of the target species. Biogeochemical analyses will include various types of chromatography and laser applications, coupled to isotope ratio mass spectrometry.

The Postdoc will be hired at Utrecht University. Much of the practical work, such as the culturing experiments with dinoflagellates and some biogeochemical analyses will be done at the at the Netherlands Institute of Ecology (NIOO-KNAW) in Wageningen and at the Royal Netherlands Institute for Sea Research (NIOZ), on Texel, respectively. The Postdoc will therefore spend much time setting up and performing culturing experiments, most likely the bulk of the time in the first year or two.

Literature references:

Hoins, M., Eberlein, T., Van de Waal, D.B., Sluijs, A., Reichart, G.-J., and Rost, B., 2016, CO2-dependent carbon isotope fractionation in dinoflagellates relates to their inorganic carbon fluxes: Journal of Experimental Marine Biology and Ecology, v. 481, p. 9-14. Hoins, M., Van de Waal, D.B., Eberlein, T., Reichart, G.-J., Rost, B., and Sluijs, A., 2015, Stable carbon isotope fractionation of organic cyst-forming dinoflagellates: Evaluating the potential for a CO2 proxy: Geochimica et Cosmochimica Acta, v. 160, p. 267-276. IPCC, 2013, Climate Change 2013: The Physical Science Basis. Working Group I Contribution to the IPCC Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Rost, B., Richter, K.-U., Riebesell, U., and Hansen, P.J., 2006, Inorganic carbon acquisition in red tide dinoflagellates: Plant, Cell & Environment, v. 29, p. 810-822. Wilkes, E.B., Carter, S.J., and Pearson, A., 2017, CO2-dependent carbon isotope fractionation in the dinoflagellate Alexandrium tamarense: Geochimica et Cosmochimica Acta, v. 212, p. 48-61.