Marie Spohn

During the last years, my work has concentrated on the following research topics.

The stoichiometry of soil organic matter
What shapes the stoichiometry of soil organic matter and how does the stoichiometry of soil organic matter affect element cycling?

Selected publications

• Spohn, M. (2024). Preferential adsorption of nitrogen-and phosphorus-containing organic compounds to minerals in soils: A review. Soil Biology and Biochemistry, 109428.
• Spohn M., and 29 others (2023). The positive effect of plant diversity on soil carbon depends on climate. Nature Communications 14, 6624.
• Spohn, M., & Stendahl, J. (2022). Carbon, nitrogen, and phosphorus stoichiometry of organic matter in Swedish forest soils and its relationship with climate, tree species, and soil texture. Biogeosciences, 19(8), 2171-2186.
• Spohn, M. (2020). Phosphorus and carbon in soil particle size fractions: A synthesis. Biogeochemistry, 147(3), 225-242.
• Spohn, M. (2020). Increasing the organic carbon stocks in mineral soils sequesters large amounts of phosphorus. Global Change Biology, 26(8), 4169-4177.

N2 fixation 
How do abiotic factors, such as C, N, and P availability and soil water content, affect N2 fixation?

Selected publications

• Vázquez, E., & Spohn, M. (2025). Non-symbiotic N2 fixation is less sensitive to changes in temperature than carbon mineralization in Northern forest soils. Geoderma, 453, 117128.
• Seuss, I., Scheibe, A., & Spohn, M. (2022). N2 fixation is less sensitive to changes in soil water content than carbon and net nitrogen mineralization. Geoderma, 424, 115973.
• Scheibe, A., & Spohn, M. (2022). N2 fixation per unit microbial biomass increases with aridity. Soil Biology and Biochemistry, 108733.
• Vázquez, E., Schleuss, P. M., Borer, E. T., Bugalho, M. N., Caldeira, M. C., Eisenhauer, N., ... & Spohn, M. (2022). Nitrogen but not phosphorus addition affects symbiotic N2 fixation by legumes in natural and semi-natural grasslands located on four continents. Plant and Soil, 1-19.
• Schleuss, P. M., Widdig, M., Biederman, L. A., Borer, E. T., Crawley, M. J., Kirkman, K. P., ... & Spohn, M. (2021). Microbial substrate stoichiometry governs nutrient effects on nitrogen cycling in grassland soils. Soil Biology and Biochemistry, 155, 108168.

Microbial biomass stoichiometry as a driver of element cycling in soils
Do stoichiometric relationships between the soil microbial biomass and soil organic matter explain element cycling in soil?

Selected publications

• Spohn, M., & Berg, B. (2023). Import and release of nutrients during the first five years of plant litter decomposition. Soil Biology and Biochemistry, 176, 108878.
  Widdig, M., Heintz-Buschart, A., Schleuss, P. M., Guhr, A., Borer, E. T., Seabloom, E. W., &
• Spohn, M. (2020). Effects of nitrogen and phosphorus addition on microbial community composition and element cycling in a grassland soil. Soil Biology and Biochemistry, 151, 108041.
• Schleuss, P. M., Widdig, M., Heintz-Buschart, A., Guhr, A., Martin, S., Kirkman, K., & Spohn, M. (2019). Stoichiometric controls of soil carbon and nitrogen cycling after long-term nitrogen and phosphorus addition in a mesic grassland in South Africa. Soil Biology and Biochemistry, 135, 294-303.
• Spohn, M. (2016). Element cycling as driven by stoichiometric homeostasis of soil microorganisms. Basic and applied ecology, 17(6), 471-478.
• Spohn, M. (2015). Microbial respiration per unit microbial biomass depends on litter layer carbon-to-nitrogen ratio. Biogeosciences, 12(3).
• Spohn, M., & Chodak, M. (2015). Microbial respiration per unit biomass increases with carbon-to-nutrient ratios in forest soils. Soil Biology and Biochemistry, 81, 128-133.
• Heuck, C., Weig, A., & Spohn, M. (2015). Soil microbial biomass C: N: P stoichiometry and microbial use of organic phosphorus. Soil Biology and Biochemistry, 85, 119-129.
• Spohn, M., & Kuzyakov, Y. (2013). Phosphorus mineralization can be driven by microbial need for carbon. Soil Biology and Biochemistry, 61, 69-75

Microbial carbon use efficiency and microbial biomass turnover
Does the availability of carbon and nutrients affect soil microbial carbon use efficiency and how can we measure this?

Microbial carbon use efficiency quantifies how microbes partition carbon between respiration and growth. In order to analyze soil microbial carbon use efficiency and microbial growth, we developed a new technique, which allows us to determine soil microbial growth and carbon use efficiency in a substrate independent way, based on the incorporation of 18O from water into the microbial DNA. The results show that microbial carbon use efficiency varies less strongly than expected and that soil C storage is more affect by the turnover of the microbial biomass than by microbial carbon use efficiency

Selected publications

• Widdig, M., Schleuss, P. M., Biederman, L. A., Borer, E. T., Crawley, M. J., Kirkman, K. P., ... & Spohn, M. (2020). Microbial carbon use efficiency in grassland soils subjected to nitrogen and phosphorus additions. Soil Biology and Biochemistry, 107815.
• Spohn, M., Pötsch, E. M., Eichorst, S. A., Woebken, D., Wanek, W., & Richter, A. (2016). Soil microbial carbon use efficiency and biomass turnover in a long-term fertilization experiment in a temperate grassland. Soil Biology and Biochemistry, 97, 168-175.
• Spohn, M., Klaus, K., Wanek, W., & Richter, A. (2016). Microbial carbon use efficiency and biomass turnover times depending on soil depth – Implications for carbon cycling. Soil Biology and Biochemistry, 96, 74-81.

Mobilization of inorganic phosphorus
What controls mobilization of inorganic phosphorus in soils?

Selected publications

• Brucker, E., Kernchen, S., & Spohn, M. (2020). Release of phosphorus and silicon from minerals by soil microorganisms depends on the availability of organic carbon. Soil Biology and Biochemistry, 143, 107737.
• Pastore, G., Kaiser, K., Kernchen, S., & Spohn, M. (2020). Microbial release of apatite-and goethite-bound phosphate in acidic forest soils. Geoderma, 370, 114360.
• Spohn, M., Zeißig, I., Brucker, E., Widdig, M., Lacher, U., & Aburto, F. (2020). Phosphorus solubilization in the rhizosphere in two saprolites with contrasting phosphorus fractions. Geoderma, 366, 114245.
• Widdig, M., Schleuss, P. M., Weig, A. R., Guhr, A., Biederman, L. A., Borer, E. T., ... & Spohn, M. (2019). Nitrogen and phosphorus additions alter the abundance of phosphorus-solubilizing bacteria and phosphatase activity in grassland soils. Frontiers in Environmental Science, 7, 185.