PaTreME was based upon a shoot chamber system developed as part of the ERC StG MEMETRE (PaTreME supervisor M. Pihlatie). The development of this system was delayed and it was not yet operational at the start of PaTreME. I therefore re-focused my activity on completing the development of this initial system, which is now operational; a description of the system has been published (Kohl et al., 2021, AMT). Furthermore, I successfully modified to measure of the chamber system to measure stable carbon isotope values of methane emissions and concurrent methanol fluxes. Attempts to measure hydrogen or radiocarbon of methane emissions were not successful, and initial measurements revealed that in practice methane fluxes were to small for meaningful carbon isotope analyses. We therefore refocused the project on quantifying the size of methane emissions from plants rather than their origin. In addition, I have re-focused my efforts of using isotope values to constrain the methane cycle to peatlands, where methane concentrations and fluxes are significantly higher than at plant surfaces. Planned field measurements at SMEAR II have not been possible due to the CoViD pandemic and technical issues,but I conducted conducted three field campaigns at the Lompolojänkkä research fen in 2021. Partitioning methane source processes of methane emissions from plant shoots based on stable isotope values was not be possible as planned because these methane fluxes are too small for stable isotope measurements. I have therefore re-focused WP4 to study methane cycling in peatlands, where both concentrations and fluxes are higher. As a first step, I have adapted the peatland methane model HIMMELI (Raivonen et al. 2017, GMD) to simulate carbon and hydrogen isotope values. This model will be used together with the measurements conducted in WP3 to quantify the fraction of methane produced in peatlands that is re-oxidized before it reaches the peat surface, an analysis similar to the one originally planned in PaTreME for plant derived methane.
Secondments: Due to the CoViD, only one physical visit to Heidelberg University was possible. Exchange with the secondment host has, however, been close and resulted in the developed two grant proposals (to the Academy of Finland).
Furthermore, I have advanced my career by taking 20 cr of university pedagogy, 30 cr of Finish language training, and grant coaching for applications to the Academy of Finland and ERC StG applications. I gained mentoring and leadership experience by (co)supervising 2 PhD students (1 ongoing, 1 withdrawn) and 2 completed MSc thesis, and submitted my application for docentship at the University of Helsinki in Jan 2022. Unfortunately, my opportunities for research communication to a wider audience were somewhat limited during the PaTreME period due to the ongoing CoViD pandemic. Unlike planned, it was therefore not possible to conduct a workshop at the Researchers Night. I have, however, produced two short videos explaining the PaTreME (and MEMETRE) research together with my PhD supervisees. Knowledge transfer was highly successful. I have become an expert in trace gas flux measurements due to training provided by the host group, seen e.g. in our technical letter (Kohl el al., 2022, New Phyt.) on this issue. Knowledge transfer from me to the host group was conducted through the joint supervision of two PhD students instead of the originally planned workshop.
