Award Dr Eva-Marie Metz receives the Environmental Award of the Viktor and Sigrid Dulger Foundation
The Heidelberg Center for the Environment (HCE), Heidelberg University’s environmental research hub, honors Eva-Marie Metz’ dissertation on the complex dynamics of greenhouse gases in the atmosphere.
In her dissertation, Eva-Marie Metz studies the global carbon cycle and the causes of significant variability in the balance of CO2 uptake and CO2 release. With her research, she was able to show that, in arid areas in the Southern Hemisphere, the release of carbon dioxide increases at the onset of rainfall after a dry period. Hence dry regions ,depending on the prevailing climatic conditions, can be both sinks and sources of CO2. Dr Metz combined this finding with observations of the respective ecosystems and with biosphere modelling. She showed that these carbon dioxide pulses are triggered by microbial respiration. In this process soil microbes, which are inactive during dry periods, are reactivated by the moisture and multiply, causing the soil to release CO2. The resulting pulses of increased CO2 release are the primary drivers of annual fluctuations in the carbon balance of arid, continental regions, such as in Australia, and thereby also play a significant role in the earth’s overall greenhouse gas balance.
Eva-Marie Metz conducted her Ph.D. work under the supervision of Dr. Sanam Vardag and Prof. Dr. André Butz at the Institute of Environmental Physics.
Related publications:
Metz, E.-M., Vardag, S. N., Feldman, A. F., Poulter, B., Colligan, T., Fischer-Femal, B. J. and Butz, A.: Responses of terrestrial ecosystem respiration to soil moisture across Australia, Environ. Res. Lett., 20(10), 104052, doi:10.1088/1748-9326/ae0051, 2025a.
Vardag, S. N., Metz, E., Artelt, L., Basu, S. and Butz, A.: CO2 Release During Soil Rewetting Shapes the Seasonal Carbon Dynamics in South American Temperate Region, Geophysical Research Letters, 52(8), e2024GL111725, doi:10.1029/2024GL111725, 2025.
Metz, E.-M., Vardag, S. N., Basu, S., Jung, M. and Butz, A.: Seasonal and interannual variability in CO2 fluxes in southern Africa seen by GOSAT, Biogeosciences, 22(2), 555–584, doi:10.5194/bg-22-555-2025, 2025b.
Metz, E.-M., Vardag, S. N., Basu, S., Jung, M., Ahrens, B., El-Madany, T., Sitch, S., Arora, V. K., Briggs, P. R., Friedlingstein, P., Goll, D. S., Jain, A. K., Kato, E., Lombardozzi, D., Nabel, J. E. M. S., Poulter, B., Séférian, R., Tian, H., Wiltshire, A., Yuan, W., Yue, X., Zaehle, S., Deutscher, N. M., Griffith, D. W. T. and Butz, A.: Soil respiration-driven CO2 pulses dominate Australia’s flux variability, Science, 379(6639), 1332–1335, doi:10.1126/science.add7833, 2023.