PhD project offered by the IMPRS-gBGC in Jan 2023


Importance of microbial necromass formation and persistence for soil carbon storage along management intensification gradients in forests and grasslands

Marion Schrumpf , Qing-Fang Bi

Background and goals

Soil organic matter (OM) is an important natural source of atmospheric CO2 concentrations and understanding the drivers of soil OM persistence is pivotal for climate change prediction and mitigation. The role of microorganisms for soil carbon cycling is dual, since they not only decompose OM but also contribute to it via necromass formation after cell death. Similar to compounds originating from decomposing plant debris, microbial necromass can become stabilised by association with minerals, thus contributing to the formation of persistent soil OM. While it was frequently observed that land use influences the relative contribution of microbial necromass to soil OM, underlying processes are not well understood. Therefore, we aim at studying, how land use and management (forest and grassland) influence both, (1) the formation and (2) the longevity of bacterial and fungal necromass in soils. Results will be related to microbial functional potentials based on carbon and nutrient cycling genes, and the observed patterns of microbial-derived soil OM and the microbial community composition at the same sites studied in a complementary second PhD project.

The study will be conducted in the framework of the DFG-funded priority program Biodiversity Exploratories (, where the effects of management intensification in forests and grasslands on biodiversity and ecosystem functioning and services are studied in three German regions. The advertised PhD project will be part of the contributing project “BIONECS”, dealing with different aspects on how land use affects the contribution of microbial-derived carbon to soil OM. The study will be done in close collaboration with a second PhD student supervised by Klaus Kaiser, Bruno Glaser (both from Martin-Luther-University Halle-Wittenberg) and Kezia Goldmann (UFZ Halle).

Your tasks will involve

  • Contribution to joint soil sampling in spring 2023
  • Determination of microbial biomass, its growth and carbon use efficiency (incorporation rates of 18O from labelled water into newly formed microbial DNA)
  • Incubation of soil samples with 13C-labelled bacterial and fungal necromass to determine their longevity in soils
  • Incubation of soil samples with 13C-labelled root litter to trace the transformation of plant- into microbial-derived carbon

Your profile

We are looking for a highly motivated and team-oriented PhD student interested in a scientific career. The successful candidate should have a broad interest in the drivers of soil carbon storage and turnover, and how those are linked to microbial composition, activity, and mineralogy. The project requires a background in soil science, soil microbiology and biogeochemical processes, which should be proven by respective courses and a master in geoecology, biogeosciences, environmental sciences, forestry, physical geography, biology, or related fields of science. Finally, very good oral and written communication skills in English are required.

Working environment

The Max Planck Institute for Biogeochemistry in Jena offers an exceptional dynamic, creative, international, and multidisciplinary working environment. The successful applicant will join the Soil Biogeochemistry group, which is encompassing experimental and theoretical work on the persistence and sensitivity of organic carbon in soils, and interactions between biogeochemical cycles of carbon, nutrients, and water at all spatial scales.

Living in Jena

The city of Jena is not only famous for its high-tech industry, internationally renowned research institutions, and a modern university, but also for its beautiful natural setting in the Saale valley with its steep limestone slopes. The climate is mild, and a large variety of plants grow in the close surroundings, including wine grapes and wild orchids. The city of Jena has a large active student scene supporting a diverse cultural life. The Max Planck Society seeks to increase the number of women in those areas where they are underrepresented and therefore explicitly encourages women to apply. The Max Planck Society is committed to increasing the number of individuals with disabilities in its workforce and therefore encourages applications from such qualified individuals. For further information, please contact Marion Schrumpf or Qing-Fang Bi).

>> more information about the IMPRS-gBGC + application