The role of microbial and invertebrate activities in shaping alpine soil respiration: current state and future scenarios
The belowground production of CO2 in soil (soil respiration, SR) represents an important terrestrial carbon source. Being correlated with soil temperature, SR is expected to exacerbate climate change. In addition, SR is expected to change considerably and in a patchy manner especially within the Alpine area, reflecting the effects of altitude, land use and climatic conditions. Previous studies measuring SR along altitudinal gradients, however, struggled with strong differences in environmental influences and with distinct unique faunal and microbial communities among samples.
The grand ambition of ACTI-RESP is to provide in-depth knowledge and quantitative information on how microbial and invertebrate communities are influenced by altitude, land use and climate change, and on how microbial activity shapes SR. To quantify the pure effect of altitude and to investigate the effects of climate and land use, I will combine field observations and a manipulative experiment within terraXcube, a facility allowing manipulations of multiple conditions including air pressure to mimic different elevations.
Thereby, I aim to further test the advantages of studying intracellular DNA (iDNA) as opposed to the generally studied environmental DNA (eDNA). Being composed by considerable amounts of extracellular DNA, eDNA does not only contain information about intact and active cells (intracellular DNA, iDNA) but also about extracellular DNA from species that might not be recently present. Here, I will study microbial agents actually shaping SR by extracting iDNA, by performing qPCR and 16S rRNA sequencing and by comparing the results to eDNA as well as RNA-based results.
In doing so, I aim to 
- define climate change-related alterations in SR
- jointly examine soil invertebrates and microorganisms
- firstly describe the pure altitude effect on microbial SR, activity and community patterns
- test iDNA quantification as a proxy for microbial activity and SR