PhD project offered by the IMPRS-gBGC in Jan 2020

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Influence of plant and soil diversity on molecular composition of dissolved organic matter (DOM)

Gerd Gleixner , Markus Lange

Project description

Dissolved organic matter (DOM) is a key component in the global carbon cycle and knowledge on its composition and reactivity is crucial to understand biogeochemical processes (1), such as nutrient cycling and organic matter storage (2). DOM, initially leached from decomposing plant material or exuded from roots, undergoes a substantial processing and recycling by soil microorganisms. Thereby, the soil microbial community remobilizes nutrients, which in turn are needed for plant growth. Thus, DOM integrates the information of production and decomposition processes (3) and helps to better understand the interactions between plants and the soil microbial community. The project will elaborate interactions between plants, the soil microbial community and the soil matrix by using an advanced ultra-high resolution mass spectrometric approach. The successful PhD candidate will analyse molecular signatures of DOM, in order to better understand the positive plant diversity effects on the ecosystem in general and specifically why this positive relation strengths over time.
The PhD candidate will work in the frame of The Jena Experiment, one of the longest running largescale biodiversity-ecosystem experiments in the world (4, 5). The central aim of the experiment is to uncover the mechanisms that determine biodiversity-ecosystem functioning relationships in the short- and in the long-term by applying novel experimental and analytical approaches (6). Supervision at the MPI-BGC is provided by Prof. Dr. Gerd Gleixner and Dr. Markus Lange. Additional expertise will be provided by Simon Benk (network analysis) Carsten Simon (fragmentation trees).

Working group and planned collaborations

The PhD candidate will work in the working group of apl. Prof. Dr. Gerd Gleixner at MPI-BGC. Additional measurements will be conducted in the labs of our cooperation partners Thorsten Dittmar (University of Oldenburg) that provide access to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Supervision at the MPI-BGC is provided by apl. Prof. Dr. Gerd Gleixner and Dr. Markus Lange. Prof. Dr. Georg Pohnert as supervisor from the Friedrich Schiller University Jena will provide additional advice on analytical chemistry.

Requirements

Applications to the IMPRS-gBGC are open to well-motivated and highly-qualified students from all countries. For this particular PhD project we seek a candidate with
  • a Master's degree in Environmental Chemistry or related sciences
  • experience in analytical chemistry, LC-MS, handling of big data sets
  • of advantage is experience in high resolution MS (FT-ICR-MS or Orbitrap)
  • very good oral and written communication skills in English
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.

References

  • J. J. Cole et al., Plumbing the Global Carbon Cycle: Integrating Inland Waters into the Terrestrial Carbon Budget. Ecosystems 10, 172-185 (2007).
  • J. C. Neff, G. P. Asner, Dissolved organic carbon in terrestrial ecosystems: Synthesis and a model. Ecosystems 4, 29-48 (2001).
  • V.-N. Roth et al., Persistence of dissolved organic matter explained by molecular changes during its passage through soil. Nature Geoscience, 1-7 (2019).
  • F. Isbell et al., Biodiversity increases the resistance of ecosystem productivity to climate extremes. Nature 526, 574-577 (2015).
  • W. W. Weisser et al., Biodiversity effects on ecosystem functioning in a 15-year grassland experiment: patterns, mechanisms, and open questions. Basic and Applied Ecology, (2017).
  • M. Lange et al., Plant diversity increases soil microbial activity and soil carbon storage. Nature Communications 6, (2015).


(a) Aerial view of The Jena Experiment, the longest-running biodiversity experiments in Europe; (b) Front view of an LC-Orbitrap MS system; (c) Plot of DOM spectra from different soil depths, analysed with ultra-high resolution mass spectrometry
(a) Aerial view of The Jena Experiment, the longest-running biodiversity experiments in Europe; (b) Front view of an LC-Orbitrap MS system; (c) Plot of DOM spectra from different soil depths, analysed with ultra-high resolution mass spectrometry


>> more information about the IMPRS-gBGC + application