Open PhD project: Ancient sediments drive modern microbial food webs
International Max Planck Research School for global Biogeochemical Cycles
The IMPRS-gBGC offers a PhD program specializing in global biogeochemistry and related Earth system sciences. The overall research and teaching focuses on:
- Improved understanding of biogeochemical processes with an emphasis on terrestrial ecosystems
- Development of observational techniques to monitor and assess biogeochemical feedbacks in the Earth system
- Theory and model development for improving the representation of biogeochemical processes in comprehensive Earth system models
Geochemistry, Mineralogy, Petrology & Volcanology (GMPV)
Soil System Sciences (SSS)
advisors: Kirsten Küsel , Valerie F. Schwab , Susan Trumbore
Life and services provided by deep soils and groundwater reservoirs are thought to depend very much on relationships between atmosphere and surface ecosystems which provide easily accessible carbon sources and energy for deeper life. However, it has been recently shown that bacteria in carbonate-rock aquifers assimilate large quantities of ancient carbon ( 14 C-free) suggesting that sedimentary rock C deposited millions of years ago can sometimes be a major energy source. Sediments are a major C reservoir on earth, and the deep terrestrial subsurface harbors a large fraction of the global microbial biomass. Therefore, understanding the mechanisms that control the sedimentary C assimilation by microorganism is essential in a better understanding of the ability of the subsurface to process ancient carbon.
This project aims to give insight into the relationships between the nature (particularly the molecular compositions) of sedimentary organic matter deposited in the terrestrial subsurface and metabolic activities in the interfaces between rock and soil and rock and groundwater. The research focuses on answering the questions: Can we relate the 13 C- and 14 C-content of specific microbe-derived molecules to nature/origin/molecular composition of bitumen extracted from sedimentary rocks? How do these molecules relate to the specific environmental conditions (O 2 content)? Which microbes have the genetic potential to process the compounds extracted from the rocks? Can we detect and trace genes responsible for the degradation of ancient organic carbon?
To answer these questions samples will be obtained among different 1) soil-sedimentary rock interfaces distinct by the content, origin or maturity (e.g. graphitization) of ancient organic matter 2) groundwaters with distinct hosting rocks (carbonate rocks, sandstones) and chemistry (samples will be collected in collaboration with CRC AquaDiva). Within the project, analytical techniques such as GC-MS and HPLC-MS will be applied to characterize the molecular diversity of the extracted sedimentary organic matter. The specific compound selected for compound specific isotope analyses will be purified by preparative-HPLC and its radiocarbon signature will be analyzed by new accelerator mass spectrometer which allows the 14 C-analyse of a few µg of C. Furthermore, genomes of the microbes present in groundwaters will be screened for their genetic potential to degrade alkanes, etc. Rock incubation experiments will be performed to link activity measurements to lipid extraction data.
Working group & planned collaborations
The PhD candidate will be affiliated to the department of Biogeochemical processes at the MPI-BGC and to the chair of Aquatic Geomicrobiology at the faculty of Biological Sciences at the Friedrich Schiller University (FSU) Jena. Supervision at the MPI-BGC is provided by Prof. Dr. Kirsten Küsel from FSU, apl. Prof. Dr. Susan Trumbore, and Dr. Valérie Schwab. Strong collaboration with others CRC AquaDiva members is expected.
Applications to the IMPRS-gBGC are open to well-motivated and highly-qualified students from all countries. Prerequisites for this PhD project are:
- a Master’s degree in Chemical Biology, Microbiology, Chemistry, Environmental Sciences with strong background in chemistry and/or molecular microbiology
- Interest in soil science, carbon cycle and or microbiology
- Experience in GC-, LC-MS and/or stable and radiocarbon isotope analyses (GC-IRMS), and/or
- Experience in omics technologies, bioinformatics and/or sample preparation for the above mentioned techniques
- Excellent oral and written communication skills in English
The Max Planck Society and the FSU Jena seeks to increase the number of women in those areas where they are underrepresented and therefore explicitly encourages women to apply. They are committed to increasing the number of individuals with disabilities in its workforce and therefore encourages applications from such qualified individuals.
How to apply
Application deadline for the fully funded PhD positions is 24 February, 2020. Pre-interviews via web conference will be carried out and promising candidates will be invited to take part in our recruitment symposium (20-22 April, 2020).