A 7500 year high-resolution lipid biomarker record from Moossee

Short Description

• Full title: Mid and Late Holocene climate and environmental history based on lipid biomarkers from Moossee, Switzerland
• Principal Investigator: Prof. Roland Zech
• Research Group: Prof. Roland Zech, Maximilian Prochnow (both Jena), Dr. Fabian Rey (University Basel), Prof. Willy Tinner (University Bern)
• Granted by: German Research Foundation, Federal State of Thuringia (Landesgraduiertenstipendium granted to Maximilian Prochnow)
• Grant: ZE860/10-1 (GEPRISExterner Link)
• Start of Project: 05 May 2024

Summary

The European Alps are highly sensitive to human impact and climate change. At times of global warming, a rapidly changing hydroclimate with heavy rainfall events, severe summer droughts and water scarcity can be observed. This will increase the risk of more frequent floods and forest fires. Robust reconstructions of past climate and environmental dynamics are needed to better understand climate-landscape interactions, and for future projections and risk assessments. While the vegetation history and temperature changes during the Holocene is well understood, multiple studies indicate strong spatio-temporal variability regarding the hydroclimate. Flood records and lake level reconstructions provide valuable information, yet not all ecologically relevant aspects, like evapotranspiration, are covered at high temporal resolution. Moreover, it is not always trivial to disentangle various influences, i.e. temperature and precipitation, but also anthropogenic effects. After all, anthropogenic activity increased a lot with the onset of the Neolithic ~7000 years ago. Over the last few years, several biomarker methods have become available, allowing to reconstruct hydrology and human impact independently. They are increasingly applied world-wide, yet no high-resolution records combining various lipid biomarkers and their compound-specific isotopic composition are available for the Alps and their forelands so far. The aim of this project is to contribute to an improved understanding of the hydroclimate, environmental and human history in the European Alps. Therefore, lipid biomarker methods will be validated and applied for lake sediments from Moossee, Switzerland. Moossee is a key site for paleoenvironmental reconstructions, because archaeological evidence (pile dwellings) documents the presence of humans since the Neolithic. The sediments are varved and extraordinarily well-dated, and we can build on a continuous high-resolution vegetation, geochemical and charcoal record.

Our project aims at the following objectives:

• To provide a robust framework for paleohydrological interpretations, we analyse modern plants and topsoils for their n-alkane pattern and compound-specific δD composition;
• We reconstruct lake water evaporation during the Mid and Late Holocene at high temporal (30 yr) resolution using compound-specific δD of aquatic and terrestrial n-alkanes;
• Polycyclic aromatic hydrocarbons and fecal biomarkers (sterols and bile acids) will be applied to reconstruct paleofire activity and to detect changes in livestock, respectively.

PAHs and fecal biomarkers will complement the existing charcoal and pollen record from Moossee, because it helps to further investigate anthropogenic influences on paleofires and possibly even cultural advances in context of archeological findings at Moossee. Our multi-lipid biomarker approach is the first of this kind and will provide valuable insights into the climate and human history of the European Alps.

Publications and other contributions

• Prochnow, M., P. Strobel, S. Acharya, L. Rittmeier, M. Bliedtner, F. Rey, W. Tinner, R. Zech (2024): A 7500 year long, 30-yr-resolution δD record from Moossee, Switzerland, indicates strong influence of solar activity on paleohydrology. Presentation @Pangeo-DEUQUA 2024 Salzburg.
• Rittmeier, L., M. Prochnow, P. Strobel, M. Bliedtner, F. Rey, W. Tinner, R. Zech: Refining Holocene environmental change and human impacts at Moossee, Switzerland, by exploring polycyclic aromatic hydrocarbons as innovative proxies for paleofire. Poster @EGU Vienna 2024. DOI: 10.5194/egusphere-egu24-16656