Articles | Volume 13, issue 7
Clim. Past, 13, 741–757, 2017
Clim. Past, 13, 741–757, 2017

Research article 03 Jul 2017

Research article | 03 Jul 2017

A dual-biomarker approach for quantification of changes in relative humidity from sedimentary lipid DH ratios

Oliver Rach1,2, Ansgar Kahmen3, Achim Brauer4, and Dirk Sachse1 Oliver Rach et al.
  • 1GFZ – German Research Centre for Geosciences, Section 5.1 Geomorphology, Organic Surface Geochemistry Lab, Telegrafenberg, 14473 Potsdam, Germany
  • 2Institute for Earth- and Environmental Science, University of Potsdam, Karl-Liebknecht-Strasse 24–25, 14476 Potsdam, Germany
  • 3Department of Environmental Sciences-Botany, University of Basel, Schönbeinstrasse 6, 4056 Basel, Switzerland
  • 4GFZ – German Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473 Potsdam, Germany

Abstract. Past climatic change can be reconstructed from sedimentary archives by a number of proxies. However, few methods exist to directly estimate hydrological changes and even fewer result in quantitative data, impeding our understanding of the timing, magnitude and mechanisms of hydrological changes.

Here we present a novel approach based on δ2H values of sedimentary lipid biomarkers in combination with plant physiological modeling to extract quantitative information on past changes in relative humidity. Our initial application to an annually laminated lacustrine sediment sequence from western Europe deposited during the Younger Dryas cold period revealed relative humidity changes of up to 15 % over sub-centennial timescales, leading to major ecosystem changes, in agreement with palynological data from the region. We show that by combining organic geochemical methods and mechanistic plant physiological models on well characterized lacustrine archives it is possible to extract quantitative ecohydrological parameters from sedimentary lipid biomarker δ2H data.

Short summary
Currently, reconstructions of past changes in the hydrological cycle are usually qualitative, which is a major drawback for testing the accuracy of models in predicting future responses. Here we present a proof of concept of a novel approach to deriving quantitative paleohydrological data, i.e. changes in relative humidity, from lacustrine sediment archives, employing a combination of organic geochemical methods and plant physiological modeling.