This project will improve our understanding of the soil C feedback from microorganisms due to climate change induced warming. Microorganisms play a crucial role in the global C cycle. The balance between the microbial release of C to the atmosphere due to respiration and microbial use of C for growth – and subsequent potential sequestration in soil – will determine if terrestrial systems become sources or sinks for atmospheric CO2. The primary physiological factor that determines how microorganisms partition their C-use into catabolic energy generation or for anabolic growth is the carbon-use efficiency (CUE). Climatic warming will affect the activity and adaptation of microorganisms, however the microbial feedback to these changes remain unknown. This microbial C-feedback to the atmosphere is probably one of the most critical, yet least known, parts of climate-C cycle modelling; emphasizing the urgency for this research. The main objective of this project is to determine the effects of soil warming on microbial CUE in different biomes and across seasons.

The PhD student project will address all three central BECC aims: (1) we will assess climate change impacts on ecosystem services (how warming will affect, and feedback to, biogeochemistry), (2) we will support regional, national and global climate-change policymakers through the scientific evaluation of policy options (integration of findings into LPJ-GUESS and EC-Earth Earth System Model (ESM), generating advice in the form of scenarios relevant to the IPCC and local and national government stakeholders via CMIP6), and (3) we will we will create and nurture a critical and lasting link between the strong research environments of empirical ecosystem ecology and biogeochemistry (dept Biology) and ecosystem modelling (INES) through joint supervision. Moreover, since LPJ-GUESS is currently coupled to the EC-Earth ESM, model developments made here can be tested in global ESM experiments beyond the core CMIP6 experiments being committed to by colleagues in SRA MERGE.