PhD project offered by the IMPRS-gBGC in

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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 such as carbon storage, CO2 release and coupling of terrestrial and marine systems (Cole et al., 2007; Tranvik et al., 2009). In order to better understand the processes that affect the origin and fate of DOM, system-specific source markers have to be identified to track the fate of DOM through various systems.
In recent studies, we demonstrated that DOM represents a snapshot of ecosystem activities and that DOM contains ecosystem-specific molecules (Roth et al., 2013; Roth et al., 2014, Roth et al., 2015). Based on these results, we want to focus our activities on the one hand on exploring the vegetation influence on the molecular composition of DOM. On the other hand want to conduct a bigger ecosystem comparison that includes a higher number of samples and ecosystems as done so far.
The proposed project will address the following research questions:
  1. What is the vegetation influence on the molecular composition of DOM?
  2. Which environmental factors influence the molecular composition of DOM in different ecosystems?

In order to address these research questions, the candidate will perform litter decomposition experiments with different plants to characterize the resulting DOM. Further, the molecular composition of a high number of DOM samples from a variety of different ecosystems including DOM samples collected at sites of the CRC AquaDiva, the Jena Experiment, MPI-BGC and other collaboration partners will be examined. Ultrahigh resolution mass spectrometry will be applied to characterize the DOM on the molecular level. A suite of complementary parameters that characterize the ecosystems will be determined by the candidate and collaboration partners

Working group and planned collaborations

The PhD candidate will work in the working group of Prof. Dr. Gerd Gleixner at MPI-BGC. Additional measurements will be conducted in the labs of our cooperation partners Thorsten Dittmar (University of Oldenburg) and Norbert Hertkorn (Helmholtz Zentrum München) that provide access to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and nuclear magnetic resonance spectroscopy (NMR). Supervision at the MPI-BGC is provided by Prof. Dr. Gerd Gleixner and Dr. Vanessa-Nina Roth. 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 Chemistry, Environmental Chemistry or other chemistry related sciences
  • experience in analytical chemistry, LC-MS, handling of big data sets
  • experience in high resolution MS (FT-ICR-MS or Orbitrap) is of advantage
  • very good oral and written communication skills in English

After you have been selected

The IMPRS-gBGC office will happily assist you with your transition to Jena. The conditions of employment, including upgrades and duration follow the rules of the Max Planck Society for the Advancement of Science and those of the German civil service. The gross monthly income amounts about 2000 EUR, which will cover all your expenses in Germany.
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

  • Cole, J. J.; Prairie, Y. T.; Caraco, N. F.; McDowell, W. H.; Tranvik, L. J.; Striegl, R. G.; Duarte, C. M.; Kortelainen, P.; Downing, J. A.; Middelburg, J. J. & Melack, J. Plumbing the global carbon cycle: Integrating inland waters into the terrestrial carbon budget. Ecosystems, 2007, 10, 171-184.
  • Roth, V.-N.; Dittmar, T.; Gaupp, R. & Gleixner, G. Latitude and pH driven trends in the molecular composition of DOM across a north south transect along the Yenisei River. Geochimica et Cosmochimica Acta, 2013, 123, 93 – 105.
  • Roth, V.-N.; Dittmar, T.; Gaupp, R. & Gleixner, G. Ecosystem-specific composition of dissolved organic matter. Vadose Zone Journal, 2014, 13, doi:10.2136/vzj2013.09.0162.
  • Roth, V.-N.; Dittmar, T.; Gaupp, R. & Gleixner, G. The molecular composition of dissolved organic matter in forest soils as a function of pH and temperature. PLoS ONE, 2015, 10(3): e0119188, doi: 10.1371/journal.pone.0119188.
  • Tranvik, L. J.; Downing, J. A.; Cotner, J. B.; Loiselle, S. A.; Striegl, R. G.; Ballatore, T. J.; Dillon, P.; Finlay, K.; Fortino, K.; Knoll, L. B.; Kortelainen, P. L.; Kutser, T.; Larsen, S.; Laurion, I.; Leech, D. M.; McCallister, S. L.; McKnight, D. M.; Melack, J. M.; Overholt, E.; Porter, J. A.; Prairie, Y.; Renwick, W. H.; Roland, F.; Sherman, B. S.; Schindler, D. W.; Sobek, S.; Tremblay, A.; Vanni, M. J.; Verschoor, A. M.; von Wachenfeldt, E. & Weyhenmeyer, G. A. Lakes and reservoirs as regulators of carbon cycling and climate. Limnology and Oceanography, 2009, 54, 2298-2314.


(a) Soil water collection; (b) Solid phase extraction of DOM; (c) FT-ICR mass spectrum of DOM.
(a) Soil water collection; (b) Solid phase extraction of DOM; (c) FT-ICR mass spectrum of DOM.


>> more information about the IMPRS-gBGC + application