Description

This PhD project aims to improve our understanding of soil organic carbon (SOC) dynamics in alpine environments, particularly under the combined effects of climate change and pastoralism. Mountain soils, though rich in carbon, are highly vulnerable and currently undergoing significant changes due to warming, altered snow cover, and shifting water regimes. Simultaneously, land use is evolving (e.g., changes in pastoral practices, greening of the alpine zone, return of large predators like wolves). The goal is to determine how pastoralism influences SOC dynamics, to assess the legacy effects of past climate and land use on these dynamics, and to characterize the microbial and organic mechanisms that govern carbon stabilization or loss.
The methodology combines two complementary approaches: an observational one, based on the study of current and historical pastoral gradients in the Alps (especially through the “Alpages sentinelles” network), and an experimental one, involving simulated climate changes combined with varying grazing intensities. A wide range of advanced analyses (including microbial sequencing, metabolomics, organic matter fractionation, radiocarbon dating, CO₂ flux measurements, lysimetry, and isotope labeling) will be used to investigate the interactions between human practices, microbial communities, and SOC dynamics. This research will provide crucial insights into how alpine soils may respond to ongoing and future global environmental changes.

Skills required

The candidate must have a very good knowledge of soils. Ideally, he/she should already have worked on organic matter dynamics and/or mountain soils. He/she should be able to work at both landscape and laboratory scales.

Bibliography

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Bonfanti, N., Clement JC., Millery-vigues A., Munkemuller T., Perrette Y., Poulenard J., 2025 Seasonal mineralization of organic matter in alpine soils and responses to global warming: an in-vitro approach. European Journal of Soil Science

Bosson, J. B., Huss, M., Cauvy-Fraunié, S., Clément, J. C., Costes, G., Fischer, M., Poulenard J. & Arthaud, F. (2023). Future emergence of new ecosystems caused by glacial retreat. Nature, 620(7974), 562-569.

Choler, P., Bayle, A., Carlson, B. Z., Randin, C., Filippa, G., & Cremonese, E. (2021). The tempo of greening in the European Alps: Spatial variations on a common theme. Global Change Biology, 27(21), 5614-5628.

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Delcourt, N., Farnet-Da Silva, A. M., Rébufa, C., Perissol, C., & Dupuy, N. (2022). Does land use legacy matter for current soil functioning? A bibliometric study (2001–2020). Environmental Reviews, 31(1), 168-181.

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Puissant, J., Cécillon, L., Mills, R. T., Robroek, B. J., Gavazov, K., De Danieli, S., ... & Brun, J. J. (2015). Seasonal influence of climate manipulation on microbial community structure and function in mountain soils. Soil Biology and Biochemistry, 80, 296-305.

Puissant, J., Mills, R. T., Robroek, B. J., Gavazov, K., Perrette, Y., De Danieli, S., ... & Cécillon, L. (2017). Climate change effects on the stability and chemistry of soil organic carbon pools in a subalpine grassland. Biogeochemistry, 132, 123-139.

Saenger, A., Cécillon, L., Poulenard, J., Bureau, F., De Daniéli, S., Gonzalez, J. M., & Brun, J. J. (2015). Surveying the carbon pools of mountain soils: A comparison of physical fractionation and Rock-Eval pyrolysis. Geoderma, 241, 279-288.

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Keywords

Soil, Organic Carbon, Mountain