Hello, my name is David Bajnai (pronounciation: ˈdaːvid ˈbɒjnɒi). I am a research associate in geochemistry at the University of Cologne.

Research Interests

My scientific goals are to reconstruct accurate and precise seawater temperatures in geological times to learn about past (and future) climates. In my research, I focus on the stable isotope fractionations that happen during biomineralisation. The stable isotope composition of the fossil remains of marine calcifiers, e.g., belemnites and brachiopods, holds information on the surrounding water temperatures. By measuring this, palaeoceanographers can postulate how warm the oceans were millions of years ago. However, isotope fractionations, so-called vital effects, bias these temperature estimates. I am using the clumped isotope (47 and 48) and the triple oxygen isotope (17O) proxies to map these vital effects, correct for them, and thus determine unbiased, accurate temperature reconstructions.

The Latest

2021-05-13: Results from an in-progress study An experimental constraint on the oxygen isotope fractionation (18O/16O) between water and aqueous hydroxide ion will be presented at the Goldschmidt online conference on 7 July 2021. Read the abstract here.

2021-04-13: New article published in Geochemistry, Geophysics, Geosystems: InterCarb: A community effort to improve inter‐laboratory standardization of the carbonate clumped isotope thermometer using carbonate standards. This community effort, led by Stefano Bernasconi and involving 22 laboratories, provides consensus 47 values for carbonate standards and describes best practices for carbonate-based standardisation. Read the open access article here.

2021-03-09: The article Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures is featured in Nature Communications’ Editor Highlights.

2020-12-31: New article published in Földtani Közlöny (in Hungarian): Modern methods of cyclostratigraphy and astrochronology and their applications. Cyclostratigraphy, the science of reading the stratigraphic record of Milankovitch cycles, i.e., climate cycles driven by periodic changes in Earth’s orbital parameters, both provides a means to measure geological time and to reconstruct palaeoclimate. Here, we review the physical drivers of cyclical changes in geological time series, introduce the steps of spectral analyses, and discuss case studies. Read the open access article here (in Hungarian). Ingyenesen olvasható magyarul itt.

2020-08-10: New article published in Nature Communications: Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures. Palaeotemperature reconstructions suffer from inaccuracies related to kinetic fractionations occurring during carbonate mineral growth. Here we show that dual clumped isotope thermometry can identify the origin of these kinetic biases and allows the reconstruction of accurate environmental temperatures. Read the open access article here. Read the press release in English here. Lies die Pressemitteilung auf Deutsch hier.

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