PhD project offered by the IMPRS-gBGC in July 2021


(How) do microorganisms control the natural molecular complexity of dissolved organic matter?

Gerd Gleixner , Manja Marz , Simon Benk

Project description

Modern analytical techniques, such as ultrahigh resolution mass spectrometry (HR-MS), have revealed a previously unseen molecular complexity in dissolved organic matter (DOM), encompassing multiple ten thousand individual molecular components. Currently, it is believed that the molecular composition of DOM is a combination of 1) a highly diverse molecular background, which is persistent, and 2) temporally and spatially variable additions of distinct metabolites, which are produced and consumed by locally active microorganisms. However, it is still unclear how a combination of individual metabolic processes finally leads to natural DOM of such high complexity. Major questions include: Is the molecular complexity of DOM a result of microbial community diversity? Or does, on the other hand, the diversity of available substrates control the microbial community composition? How long does it take for complexity to emerge from low-diversity systems? Does the rate of change depend more on the microbial or molecular diversity? Initial attempts at reconstructing microbial metabolic functions for the processing of natural substrates suggest that microbial and molecular systems are indeed highly coupled, supporting results from biodiversity research which show beneficial effects of high diversity on natural ecosystem functioning.

The successful candidate will conduct experiments on the microbial processing of natural substrates with gradients in the complexity of DOM and microbial communities, from single compounds and single organisms to community-level decomposition of complex natural substrates. The results of the simultaneous monitoring of the molecular composition of DOM and the active microbial communities will be combined in a biochemical reaction model. The resulting model will be scalable from single processes to natural complexity and will inform about ecosystem functioning in uniform or diverse environments. The successful candidate will have access to state-of-the-art HR-MS and molecular biology facilities as well as computing resources at the MPI-BGC and will work closely with cooperation partners both locally at the FSU and abroad.

We seek a highly motivated candidate that is interested in revealing detailed interactions between molecules and microorganisms. The ideal candidate will have:
  • a university degree in environmental sciences, chemistry, biology or a related field
  • experience with analytical techniques and biochemistry lab work
  • experience with data analytics using python, matlab or R
  • experience in the development of models
  • excellent oral and written communication skills in English

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. Furthermore, the Max Planck Society seeks to in-crease the number of women in those areas where they are underrepresented and therefore explicitly encourages women to apply.

>> more information about the IMPRS-gBGC + application