The end of a journey!

Turry Ouma first came to Switzerland in 2022 to begin her PhD on the N2O-SSA project, Combining measurements, modelling and machine learning to improve N₂O accounting for sustainable agricultural development in sub-Saharan Africa. She spent a year in Kenya in 2023-24 conducting a major fieldwork experiment. This challenging campaign used a variety of methods, particularly automated chambers and isotope measurements, to produce one of the most detailed datasets ever collected in this region. The results suggest that complete denitrification - the reduction of N₂O to N₂ - could be responsible for low N₂O emission factors in Kenyan agricultural soils.

Following an excellent presentation, Turry passed her defense and received her doctoral hat. Thanks to Stuart Grange for photos!

On the 29th of June, 2026, a large audience gathered in the main building of ETHZ to listen to Turry defend her PhD thesis. The examination committee - Profs. Eliza Harris, Johan Six, and Longfei Yu - led by the chair Prof. Ulrike Lohmann, agreed to accept Turry's thesis and defense and grant her the doctoral degree. And with this major step, a long journey approaches its end. We look forward to seeing what comes next for Turry and her family!

Turry's thesis was supported by many different groups: The Isotope Biogeoscience N2OSSA team, the Swiss Data Science Centre team, and (most importantly), her family. Thanks to Stuart Grange for photos!