Hydrological and ecological changes in western Europe between 3200 and 2000 years BP derived from lipid biomarker δD values in lake Meerfelder Maar sediments

Rach, Oliver; Engels, Stefan; Kahmen, A.; Brauer, Achim; Mart�n-Puertas, Celia; van Geel, Bas; Sachse, Dirk

Abstract

One of the most significant Late Holocene climate shifts occurred around 2800 years ago, when cooler and wetter climate conditions established in western Europe. This shift coincided with an abrupt change in regional atmospheric circulation between 2760 and 2560 cal years BP, which has been linked to a grand solar minimum with the same duration (the Homeric Minimum). We investigated the temporal sequence of hydroclimatic and vegetation changes across this interval of climatic change (Homeric climate oscillation) by using lipid biomarker stable hydrogen isotope ratios (δD values) and pollen assemblages from the annually-laminated sediment record from lake Meerfelder Maar (Germany).

Over the investigated interval (3200–2000 varve years BP), terrestrial lipid biomarker δD showed a gradual trend to more negative values, consistent with the western Europe long-term climate trend of the Late Holocene. At ca. 2640 varve years BP we identified a strong increase in aquatic plants and algal remains, indicating a rapid change in the aquatic ecosystem superimposed on this long-term trend. Interestingly, this aquatic ecosystem change was accompanied by large changes in δD values of aquatic lipid biomarkers, such as nC21 and nC23 (by between 22 and 30‰). As these variations cannot solely be explained by hydroclimate changes, we suggest that these changes in the δDaq value were influenced by changes in n-alkane source organisms. Our results illustrate that if ubiquitous aquatic lipid biomarkers are derived from a limited pool of organisms, changes in lake ecology can be a driving factor for variations on sedimentary lipid δDaq values, which then could be easily misinterpreted in terms of hydroclimatic changes.

Citation

Rach, O., Engels, S., Kahmen, A., Brauer, A., Martín-Puertas, C., van Geel, B., & Sachse, D. (2017). Hydrological and ecological changes in western Europe between 3200 and 2000 years BP derived from lipid biomarker δD values in lake Meerfelder Maar sediments. Quaternary Science Reviews, 172, https://doi.org/10.1016/j.quascirev.2017.07.019

• Journal Article Type: Article
• Acceptance Date: Jul 22, 2017
• Online Publication Date: Aug 1, 2017
• Publication Date: Sep 15, 2017
• Deposit Date: Aug 2, 2017
• Publicly Available Date: Aug 2, 2018
• Journal: Quaternary Science Reviews
• Print ISSN: 0277-3791
• Electronic ISSN: 1873-457X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 172
• DOI: https://doi.org/10.1016/j.quascirev.2017.07.019
• Keywords: Holocene; Climate dynamics; Paleoclimatology; Western Europe; Continental biomarkers; Organic geochemistry; Stable isotopes; Vegetation dynamics
• Public URL: https://nottingham-repository.worktribe.com/output/882777
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0277379117302305
• Contract Date: Aug 2, 2017