Home | Contact | Deutsch  | CSI project

Department of Geography 

Department organizationStudyingGraduate SchoolUnitsEventsServicesLibrary

Team

Samuel Abiven
Nimisha Singh
Bernardo Maestrini
Ivan Woodhatch
Michael Hilf
Claudia Schreiner
Michael W.I. Schmidt

Collaboration

Jeff Bird (Queens College)
Margaret Torn (Berkeley Lab)

PhD and students projects related to the CSI Swiss project

Bernardo Maestrini - PhD - C and N budget of pyrogenic Carbon in the soil (Supervision Samuel Abiven)
Nimisha Singh - PhD - Fate of Pyrogenic Carbon in the soil, processes of decomposition (Supervision Samuel Abiven)
Pascal Hendgartner - Master - Solubility of pyrogenic compounds into the soil dissolved organic matter (Supervision Samuel Abiven)
Mirjam Studer - Bachelor - Use of Diffuse Infra-Red Fournier Transformed Spectrometry to characterize char (Supervision Samuel Abiven)
Romano Andreoli - Bachelor - Mixing char and different wood substrats, consequences on decomposition (Supervision Samuel Abiven)
Fabian Züst - Bachelor - Decomposition of charcoal, measure of CO2 in the field (Supervision Samuel Abiven)
Sara Bösch and Ryan Christinger - Bachelor - Set up of the field design (Supervision Samuel Abiven)

Char Studies Initiative (CSI) Switzerland

Because of global change, future summers in temperate regions will be warmer and drier than today, and wildfires will be more frequent, producing more fire-derived (pyrogenic) carbon (PyC). Quantitative information on the long-term fate of PyC in soil is still virtually absent (Fig. 1). Because of it highly aromatic structure, it has been considered as inert or recalicitrant in the soil. This point has been re-considered lately.

 

Another aspect of global change concerns the increase of nitrogen (N) deposition on the terrestrial ecosystems. This additional input of mineral N has an effect on plants (i.e. fertilisation), but also on the soil organic matter, thus it is not clear whether SOC will decompose faster or slower under these future conditions. Regarding PyC degradation, this information is virtually absent.

Figure 1: C cycle and uncertainty due to Pyrogenic C (Preston and Schmidt, 2007)Figure 1: C cycle and uncertainty due to Pyrogenic C (Preston and Schmidt, 2007)

Figure 2: Experimental designFigure 2: Experimental design

 

In the project, we propose to identify underlying processes of char and wood degradation under high and low nitrogen —by directly identifying micro-organisms decomposing PyC through the double label (13C, 15N), by describing microorganism community structures, by determining the alteration of the PyC chemical structure of the remaining char (CPMAS 13C and 15N NMR, BPCA molecular markers) in the dissolved fraction and in the bulk soil and by using the isotopes to trace the degradation products within the soil fractions.

 

This project is novel and cutting-edge for several reasons: For the first time, (1) we directly identify PyC decomposers, (2) we directly quantify PyC degradation in vivo in a long-term field study, and (3) we test the effect of nitrogen on decomposition of PyC and its wood precursor.

 

Technical aspects
In this long-term experiment, cylindrical mesocosms have been installed in the soil and filled with (1) 13C/15N labelled pyrolyzed wood, (2) 13C/15N labelled wood and (3) a no-litter control, either treated with mineral nitrogen or not, resulting in a two-factor, two-treatment experiment (see figure 2). 

top