How vulnerable are groundwater microbiomes in European Critical Zone Observatories (CZOs)? |
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Kirsten Küsel,
Gerd Gleixner
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Project descriptionThe Critical Zone (CZ) reaches from the lower troposphere to the rivers, soils and aquifers of the Earth’s near surface and encompasses the whole terrestrial biosphere (Brantley et al., 2017). This zone is deemed “critical” because it represents the major interface where crucial biogeochemical processes of water (retention in soil, formation of rain) and carbon cycling (nutrient remineralization, C sequestration, photosynthesis and growth) and microbial processing take place (Roth et al., 2019; Spracklen et al., 2018). Dissolved or colloidal organic molecules are important ecological and biochemical signals (“biomarkers”) that mediate and reflect these processes (Bourtsoukidis et al., 2018; Malik et al., 2020; Roth et al., 2019), and play a significant role in the distribution of nutrients and trace elements (Kretzschmar & Schäfer, 2005; Yan et al., 2014). Soil-borne microorganisms are transported with the soil seepage water into the subsurface and some of them can finally reach and thrive in the groundwater (Herrmann et al., 2023). Weather extremes, like heavy rainfalls after a summer drought might bypass the filter function of the soil and transfer more surface signals and microorganisms into the groundwater. However, these processes are little understood, especially how the microbial communities are responding to changes in habitat and climate.Therefore, we will analyze microbial communities of several groundwater biomes (see picture showing groundwater access in the Äspö Hard Rock tunnel in Sweden) having different geological lithologies, flow regimes, surface vegetation and climate zones in Europe (see Map) and compare them with surface communities. Research aim & questionsThe overall research aim is: to analyze the vulnerability of European groundwater by analyzing the similarity of microbial groundwater and surface communities as higher similarity shows higher vulnerability. Based on existing information from the European CZOs, we will analyze the driving factors for the community structure and the genomic potential of the microbial community. The results will be compared to results from molecular fingerprints of dissolved organic matter (independent PhD thesis), the composition of intact polar lipids (independent PhD thesis) and the ability of ecosystems for free living nitrogen fixation (independent Master Thesis). Within this IMPRS project, the candidate will build upon an established collaboration between the Friedrich Schiller University Jena and the Max Planck Institute for Biogeochemistry with strong links to the CRC AquaDiva.Applied techniquesWithin the project, soil and groundwater microbiomes will be analyzed using 16S rRNA amplicon sequencing. Selected sites will be further analyzed using metagenomics to obtain taxonomic and functional patterns and metagenome-assembled genomes (MAGs). MAGs will be used to elucidate genomic potentials which will be linked with DOM characteristics and metabolites.Affiliation and supportThe PhD candidate will be affiliated to the chair “Aquatic Geomicrobiology” at the Institute for Biodiversity at FSU Jena and the “Molecular Biogeochemistry” group at MPI-BGC. The successful PhD candidate jointly work with two other Phd candidates and a master student on the project, which will most likely enhance the impact of this research project.RequirementsApplications to the IMPRS-gBGC are open to highly motivated and qualified students from all countries. For this particular PhD project we seek a candidate with
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