Our research lays the foundation for robust global models of land-ocean biogeochemical matter fluxes and chemical weathering. Those can be implementated into Earth System Models to analyse their feedback potential and strength in the climate system at different time scales. Therefore the research group has set up two kinds of laboratories as basic infrastructure: 1) a GIS-laboratory for developing new geodata; 2) a hydrochemical laboratory, to parameterize transformation processes. High temporal and/or spatial resolution field and mesocosm studies are conducted to reveal missing essential empirical parameters and budgets.
1. Global scale matter fluxes
Pairing high resolution global spatial data with regional hydrochemical data (GLORICH database), we develop a new global weathering model framework to quantify spatially explicit CO2-consumption by chemical weathering as well as land-ocean carbon and nutrient fluxes. The GLORICH database is also used to estimate global seasonal outgassing of CO2 from limnic and estuarine systems with high spatial resolution. In addition, transformation rates of biogeochemical matter entering the transition zone before release to the ocean are quantified by combining a coastal zone typology with GLORICH.
2. The fate of carbon and nutrients in aquatic systems
The capacities of the hydrochemical laboratory and of cooperation partners help us to understand the fate of terrestrial carbon and nutrients in the land-ocean-aquatic continuum. The amount of processed terrestrial carbon released from the aquatic system to the atmosphere will be analyzed for the Elbe-estuary and seasonal input budgets will be provided to constrain boundary conditions of ecosystem models of the North Sea.
3. Feedbacks of land-ocean matter fluxes
We use results of the developed land-ocean matter flux models to parameterize a land-ocean-matter flux module of coarser resolution for Earth System Models, recognizing inorganic and organic carbon, silica and liberation of phosphorus to ecosystems.
4. Enhanced weathering
The term “Enhanced Weathering” in the context of Greenhouse Gas Removal methodologies describes the application of rock powder to sequester CO2 by chemical weathering in terrestrial or aquatic systems. Besides the sequestration of CO2, depending on the used rock, geogenic nutrients are released. We analyze the applicability of the geoengineering concept of artificially enhanced weathering considering aspects of climate change and security.
For our data-intensive research we have developed two global databases which we employ and share with colleagues:
- Gaillardet, J., Calmels, D., Romero-Mujalli, G., Zakharova, E., & Hartmann, J. (2019). Global climate control on carbonate weathering intensity. Chemical Geology, 118762. doi:10.1016/j.chemgeo.2018.05.009.
- Romero Mujalli, G., Hartmann, J., & Börker, J. (2019). Temperature and CO2 dependency of global carbonate weathering fluxes – Implications for future carbonate weathering research. Chemical Geology. doi:10.1016/j.chemgeo.2018.08.010.
- Cuthbert, M. O., Gleeson, T., Moosdorf, N., Befus, K. M., Schneider, A., Hartmann, J., Hartmann, J., & Lehner, B. (2019). Global patterns and dynamics of climate–groundwater interactions. Nature Climate Change, 9(2), 137-141. doi:10.1038/s41558-018-0386-4.
- Minx, J. C., Lamb, W. F., Callaghan, M. W., Fuss, S., Hilaire, J., Creutzig, F., Amann, T., Beringer, T., Garcia, W. d. O., Hartmann, J., Khanna, T., Lenzi, D., Luderer, G., Nemet, G., Rogelj, J., Smith, P., Vicente, J. L. V., Wilcox, J., & Dominguez, M. d. M. Z. (2018). Negative emissions—Part 1: Research landscape and synthesis. Environmental Research Letters, 13(6): 063001, pp. 1-30. doi:10.1088/1748-9326/aabf9b.