An autonomous, multi-cuvettes laser-spectrometer system to study leaf photosynthetic isotope discrimination, CO2 exchange and volatile organic compound (VOC) emissions (A03)

• Subject Area: Ecology and Biodiversity of Plants and Ecosystems ; Microsystems
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 459819582

A3.1 Spatial and temporal resolution of leaf 13CO2 and VOC fluxesWe will capture spatial and temporal dynamics in leaf gas exchange within and among tree crowns in a mixed forest. Environmental impact can be identified by 13C-isotope discrimination during photosynthesis, reflecting changes water use efficiency. Volatile organic compound (VOC) emissions are further sensitive tracers of abiotic and biotic stress, which can reveal hot spots and hot moments of these key fluxes. A3.2 Development of miniaturized leaf cuvettes and compact laser spectrometer for 13CO2 isotopesMicro gas cuvettes will be developed and deployed in large numbers to monitor the 3D-variability of 13CO2 isotope discrimination within the canopy. Equipped with an integrated open-close mechanism, they will be connected to multiple small, low-cost carbon isotope laser spectrometers, which will also measure leaf H2O fluxes. As the laser spectrometers cannot be miniaturized to a similar extent as the leaf cuvettes, they will be placed at a central position and connected by tubing.

• DFG Programme: Collaborative Research Centres
• Subproject of: SFB 1537: ECOSENSE – Multiscale quantification of spatio-temporal dynamics of ecosys-tem processes by smart autonomous sensor networks
• Applicant Institution: Albert-Ludwigs-Universität Freiburg
• Project Heads: Dr. Simon Haberstroh; Dr. Katrin Schmitt; Professorin Dr.-Ing. Ulrike Wallrabe; Professorin Dr. Christiane Werner