Dr. Sönke Zaehle
Phone: +49 (0)3641 57 - 6230
The aim of our Department Biogeochemical Signals is to improve our understanding of the interactions between element cycles of the land surface and of the atmosphere on local, regional and global scales, and thus to make better predictions on the impact of climate change. In addition to the essential and climate-relevant cycles of carbon and water, our research focuses on the plant nutrients nitrogen (N) and phosphorus (P) and their importance for plant growth, water balance and the carbon cycle.
We combine knowledge about eco-physiological processes with observations and modelling of biogeochemical cycles at different spatial scales. Exemplary questions deal with the effect of nutrient availability on the CO2 fertilization of the vegetation, or the influence of nitrogen input on the storage capacity of carbon in soils. We also investigate how the reactions of terrestrial ecosystems change in a changing climate and what role the exchange with the atmosphere plays in this.
To answer such questions, we develop complex models to simulate biogeochemical element cycles and their dependence on vegetation and soil properties as well as local climate. Based on his expert knowledge of physiological principles of ecosystem processes, we seek to improve these models and adapt them better to reality. We subsequently test the improved models with different types of ecosystem and atmospheric observations. Our new findings also feed into global models of the Earth system to estimate the impact of increasing human influence on terrestrial ecosystems.
Meyerholt, J., Sickel, K., Zaehle, S. (2020). Ensemble projections elucidate effects of uncertainty in terrestrial nitrogen limitation on future carbon uptake. Global Change Biology, 00: 1– 19. https://doi.org/10.1111/gcb.15114
Thum, T., et al., Zaehle, S. (2019). A new terrestrial biosphere model with coupled carbon, nitrogen, and phosphorus cycles (QUINCY v1.0; revision 1772). Geoscientific Model Development, 12(11), 4781-4802. doi:10.5194/gmd-12-4781-2019.
Knauer, J., Zaehle, S., et al. (2017). The response of ecosystem water-use efficiency to rising atmospheric CO2 concentrations: sensitivity and large-scale biogeochemical implications. New Phytologist, 213(4), 1654-1666. doi:10.1111/nph.14288.
Medlyn, B.E., Zaehle, S. et al. (2015) Using ecosystem experiments to improve vegetation models. Nature Climate Change, doi:10.1038/nclimate2621
Zaehle, S. et al. (2014) Evaluation of 11 terrestrial carbon–nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies. New Phytologist, 202, 803-822.
Zaehle, S., Ciais P., Friend A.D., Prieur V. (2011) Carbon benefits of anthropogenic reactive nitrogen offset by nitrous oxide emissions. Nature Geoscience doi:0.1038/NGEO1207.