Dr. Maja Barbara Siegenthaler

I am a soil biogeochemist with a background in agricultural sciences. My research is driven by curiosity about carbon and nutrient cycling in the soil-microbe-plant system and its response to environmental change. I have previously investigated major and trace nutrient (i.e., P, N, S, Se) cycling and speciation in soils. At WSL, I am focusing on C turnover along forest elevation gradients.

07/2026 to present: Postdoc – carbon fractions and turnover along elevation gradients
Soil Biogeochemistry Group, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Switzerland

06/2024 to 06/2026: Postdoc – role of microbes in carbon and nutrient cycling in soil
Department of Physical Geography, Stockholm University, Sweden

01/2023 to 03/2024: Postdoc – selenium speciation in soil
Group of Environmental Inorganic Geochemistry, Department Water Resources and Drinking Water, Eawag, Switzerland

04/2022 to 12/2022: Postdoc – soil geochemistry
Swiss Soil Monitoring Network, Environment and Resources, Agroscope, Switzerland

11/2017 to 10/2021: PhD candidate – phosphorus cycling in beech forests
Group of Plant Nutrition, Institute of Agricultural Sciences, ETH Zürich, Switzerland

2022 – PhD Soil Biogeochemistry, ETH Zurich, Switzerland

2017 – MSc Agroecosystem Science, ETH Zurich, Switzerland

2015 – BSc Agricultural Science, ETH Zurich, Switzerland

OrcidID: https://orcid.org/0000-0001-8764-2767 

Manzoni S, Siegenthaler M, Ghersheen S, Lindahl B, Spohn M (2026) More efficient nitrogen recycling or less efficient carbon use to decompose nitrogen-poor residues? Tellus A: Dynamic Meteorology and Oceanography. https://doi.org/10.16993/tellus.4114 

Siegenthaler MB, Winkel LHE., Meuli RG., Tolu J (2026) Organic selenium quality and quantity in soils are related to organic matter composition and driven by land use. Environmental Science & Technology. https://doi.org/10.1021/acs.est.5c15430 

Siegenthaler MB, McLaren TI, Frossard E, Tamburini F (2024) Dual isotopic (33P and 18O) tracing and solution 31P NMR spectroscopy to reveal organic phosphorus synthesis in organic soil horizons. Soil Biology and Biochemistry 197:109519. https://doi.org/10.1016/j.soilbio.2024.109519 

Reusser JE, Siegenthaler MB, Winkel LH, Wächter D, Kretzschmar R, Meuli RG (2023) Geochemischer Bodenatlas der Schweiz: Verteilung von 20 Elementen in den Oberböden. Agroscope & Bundesamt für Umwelt (BAF). Agroscope Spezialpublikation, https://doi.org/10.34776/gca23-g (available in German, French, Italian, and English)

Siegenthaler MB, Ramoneda J, Frossard E, Mészáros É (2022) Microbial community responses to phosphorus and nitrogen inputs in the organic soil horizons of two contrasting temperate beech forests. Applied Soil Ecology 172:104357. https://doi.org/https://doi.org/10.1016/j.apsoil.2021.104357 

Siegenthaler MB, Tamburini F, Frossard E, Chadwick O, Vitousek P, Pistocchi C, Mészáros É, Helfenstein J (2020) A dual isotopic (32P and 18O) incubation study to disentangle mechanisms controlling phosphorus cycling in soils from a climatic gradient (Kohala, Hawaii). Soil Biology and Biochemistry 149:107920. https://doi.org/10.1016/j.soilbio.2020.107920