Prof. William Orsi
Professor für Geomikrobiologie
LMU
Postanschrift:
Richard-Wagner-Str. 10
80333 München
About me
The Orsi geomicrobiology lab was started in 2016 in the Department of Earth Sciences at Ludwig-Maximilians-Universität München (University of Munich). As of 2024 the group has produced four PhD students, three postdocs, and more than 13 Master student theses. In addition, a number of international visiting scholars, colleagues, postdocs, PhD students have visited over the years which makes for an active and engaging research environment. We value interdisciplinary science and creative thinking. In all of our projects we value teamwork because we believe that TEAM stands for "Together Everyone Achieves More".
since 2017 Director of the Mentoring Program at LMU Munich (Faculty of Geoscience).
since 2022 Chair of the executive committee for the Munich GeoCenter
Research
Microorganisms influence the composition of the atmosphere, the cycling of elements within and through ecosystems, and the functioning of ecosystems. Microorganisms are also the most metabolically flexible, and the most taxonomically and evolutionarily diverse organisms on Earth. Yet deciphering how that diversity influences biogeochemical processes at larger scales is a challenge, because of the overwhelming complexity of microbial communities makes it difficult to quantify how microbial taxa assimilate and transform elements in the environment.
We use a combination of methods that blend traditions from microbial ecology including stable isotope probing, genomic, gene expression, and GC-MS tools to investigate how the diversity and physiology of microorganisms shape carbon cycling of ecosystems. Our research is derived primarily from field observations, as well as DNA and RNA stable isotope labeling experiments. We are focused on the microbial and biochemical mechanisms underlying the biogeochemical cycling of carbon, and its processing through microbial feeding chains.
© William Orsi
Aquatic Microbial Carbon Cycle
Microorganisms influence the composition of the atmosphere, the cycling of elements within and through ecosystems, and the functioning of ecosystems. Microorganisms are also the most metabolically flexible, and the most taxonomically and evolutionarily diverse organisms on Earth. Yet deciphering how that diversity influences biogeochemical processes at larger scales is a challenge, because of the overwhelming complexity of microbial communities makes it difficult to quantify how microbial taxa assimilate and transform elements in the environment.
We use a combination of methods that blend traditions from microbial ecology including stable isotope probing, genomic, and gene expression tools to explore how the diversity and physiology of microorganisms shape the biogeochemistry of marine ecosystems. Our research is derived primarily from field observations, as well as DNA and RNA stable isotope labeling experiments. Our research is primarily focused on the biological and biochemical mechanisms underlying marine microbial loops: the biogeochemical cycling of carbon and its processing through microbial food webs in the ocean.
Running Projects
- Ozeanographische Forschungsfahrt EreBUS
- Aufschlüsselung der Nahrungskette von magnetotaktischen Bakterien zu Protozoen unter Labor- und Umweltbedingungen (DFG, SPP2404 DeepDyn, seit 2023)
- Magnetofossilation: Bildung und Erhalt von Magnetosomen in Sedimenten (DFG, SPP2404 DeepDyn, seit 2024)
William D Orsi, Jason M Smith, Shuting Liu, Zhanfei Liu, Carole M Sakamoto, Susanne Wilken, Camille Poirier, Thomas A Richards, Patrick J Keeling, Alexandra Z Worden, Alyson E Santoro: Diverse, uncultivated bacteria and archaea underlying the cycling of dissolved protein in the ocean, The ISME Journal, Volume 10, Issue 9, September 2016, Pages 2158–2173, https://doi.org/10.1038/ismej.2016.20
Einsiedl, F., Wunderlich, A., Sebilo, M., Coskun, Ö. K., Orsi, W. D., and Mayer, B.: Biogeochemical evidence of anaerobic methane oxidation and anaerobic ammonium oxidation in a stratified lake using stable isotopes, Biogeosciences, 17, 5149–5161, https://doi.org/10.5194/bg-17-5149-2020, 2020.
Sedimentkern
Die Grünfärbung ist charakteristisch für Sedimente vor Namibias Küste und geht auf hohe Konzentration von eisenhaltigen Mineralien zurück. | © William Orsi
Deep Biosphere
Scientific ocean drilling has revealed a deep biosphere of widespreadmicrobial life in sub-seafloor sediment. Microbial metabolism in the marine subsurface probably has an important role in global biogeochemical cycles, but deep biosphere activities are not well understood. Life in these settings subsist over long timescales under extreme energy limitation, the levels of activity are very low and therefore it is a major challenge to measure the activity of cells in these settings to determine their role in the subsurface ecosystem. We use a combination of genomic, transcriptomic, and quantitative stable isotope probing (qSIP) methods to investigate the metabolism of microbial life that exists deep below the Earth surface and survives over long (millions of years) timescales. A major goal is to quantify the role of individual microbial taxa within the complex carbon flows that occur within these extremely energy limited ecosystems. Further information on Center for Dark Energy Biosphere Investigation
Orsi, W., Edgcomb, V., Christman, G. et al. Gene expression in the deep biosphere. Nature 499, 205–208 (2013). https://doi.org/10.1038/nature12230
William D. Orsi, Tobias Magritsch, Sergio Vargas, Ömer K. Coskun, Aurele Vuillemin, Sebastian Höhna, Gert Wörheide, Steven D’Hondt, B. Jesse Shapiro, Paul Carini. Genome evolution in bacteria isolated from million-year-old subseafloor sediment. bioRxiv 2020.12.19.423498; doi: https://doi.org/10.1101/2020.12.19.423498
Hydrothermal Microbial Ecology
Hydrothermal habitats offer a window into deep earth processes and provide a unique habitat for life that is adapted to grow at high temperatures and under unique geochemical conditions for example extreme acidic or alkaline conditions. We are interested in questions such as what are the limits to life in such "extreme" habitats and what does this teach us about the emergence of life and the possibility for life on other habitable worlds. Research is derived from field observations involving genomic, gene expression, and stable isotope labeling experiments to better understand how metabolism and carbon fixation mechanisms operate in hydrothermal settings across steep chemical gradients and temperature gradients. We also perform experiments in the lab whereby we create hydrothermal chimneys across eH and pH gradients under a controlled anoxic atmosphere to study how the mineral diversity and chemical transformations (for example of gases) are linked to biological activity and the potential implications for prebiotic chemistry in simulated Hadean hydrothermal systems.
Ribozyme trapping in ferruginous chemical gardens im TRR 392 Molecular Evolution in Prebiotic Environments (seit 2024), dem Nachfolger des Sonderforschungsbereich SFB235: Emergence of Life (2018 - 2023)
Prüfung der Bewohnbarkeit alkalischer hydrothermaler Schlote in einer simulierten Hadean-Ozeanumgebung (DFG, seit 2023)
Coskun, Ö.K., Vuillemin, A., Schubotz, F., Klein F., Sichel S.E., Eisenreich W., Orsi W.: Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. ISME J 16, 257–271 (2022). https://doi.org/10.1038/s41396-021-01066-x
F. Klein, S.E. Humphris, W. Guo, F. Schubotz, E.M. Schwarzenbach, & W.D. Orsi: Fluid mixing and the deep biosphere of a fossil Lost City-type hydrothermal system at the Iberia Margin, Proc. Natl. Acad. Sci. U.S.A. 112 (39) 12036-12041, https://doi.org/10.1073/pnas.1504674112 (2015).