The year 2022 was a year of catastrophic extreme climatic events at an unprecedented scale. Rivers around the globe drying up, China's extreme heat wave, extreme floods in Pakistan and in the United States, are clear examples of a climate change scenario that is expected to be more and more pervasive in the next years. Despite evidence of the increase in frequency and intensity of extreme events, the effects of the extreme oscillations between droughts and floods on streams carbon cycling are still uncertain. Alpine streams are important contributors of inland water carbon and changes that occur in alpine streams can profoundly alter downstream reaches affecting the global carbon budget and in turn exacerbate climate impact in the future. PeriCarb, EFA aims at understanding how periphyton biofilms community composition changes due to extreme flow change events and the reduction in the recovery time for the microbial community between events. It will link biofilm changes in community composition to changes in carbon cycling and in greenhouse emissions. By linking microbial ecology and carbon biogeochemistry changes in alpine streams PeriCarb will inform on the impact of climate change on global carbon budgets. PeriCarb will constitute a multidisciplinary project joining the applicant's previous experience with the excellence of the host institution and a group of established collaborators. It will provide advances for the field of carbon biogeochemistry and allow the applicant to return to Europe to establish as a researcher.