Links and Functions

Breadcrumb Navigation


Curriculum Vitae


  • 2020-Present Professor (W2, with Tenure), Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians Universität (LMU) München

  • 2016-2020 Professor (W2, tenure-track), Department of Earth and Environmental Sciences, Paleontology and Geobiology,Ludwig-Maximilians Universität (LMU) München
  • 2014-2015 Postdoctoral Investigator, Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution (WHOI)
  • 2013-2014 Assistant Research Scientist, Horn Point Laboratory, University of Maryland Center for Environmental Sciences (UMCES)
  • 2011-2013 Postdoctoral Fellow, Department of Geology and Geophysics, Woods Hole Oceanographic Institution (WHOI)
  • 2006-2011 Graduate Researcher, Biology Department, Northeastern University


  • 2006-2011 Ph.D. in Biology, Northeastern University
    (Advisor: Prof. Dr. Slava S. Epstein)
  • 2002-2006 B.S. in Biology with honors, Temple University
    (Advisor: Prof. Ee Lin Lim)

Research Awards

  • 2023-2026 German National Research Foundation (DFG) grant awarded (€ 247,477): “Investigating the food chain from magnetotactic bacteria to protozoa under laboratory and environmental conditions”. Principle Investigator: William Orsi.
  • 2023-2026 German National Research Foundation (DFG) grant awarded (€ 260,000): “Testing the habitability of simulated Hadean hydrothermal vent ecosystems”. Principle Investigator: William Orsi.
  • 2022-2025 German National Research Foundation (DFG) grant awarded (€ 565,000): “Illuminating the ecology of marine fungi using quantitative stable isotope probing”. Principle Investigator: William Orsi.
  • 2021-2022 DFG Excellence Initiative Investitionsfonds Award (€ 100,000): “Radiolysis and deep life”. Principle Investigator: William Orsi.
  • 2018-2021 German National Research Foundation (DFG) grant awarded (€ 480,000): “Tracing primordial metabolism reflected by microorganisms at hydrothermal vents
  • 2017-2020 German National Research Foundation (DFG) grant awarded (€ 360,000): “Aerobic microbial activity in deep sea abyssal clay
  • 2016-2017 Junior Researcher Award (DFG excellence initiative) research grant awarded: “Genome evolution over geological timescales in marine sediment”
  • 2014-2015 Deep Ocean Exploration Institute (WHOI) research grant awarded:
    “Geosphere-biosphere interactions at a cretaceous “Lost City’-type hydrothermal system at the Iberia Margin”
  • 2014-2015 Center for Dark Energy Biosphere Investigations research grant awarded: “Microbial activity in oxygenated subseafloor sediment”
  • 2014 Center for Dark Energy Biosphere Investigations Research Travel and Exchange grant awarded
  • 2012-2013 Ocean Life Institute (WHOI) research grant awarded:
    “Presence and activity of subseafloor Fungi in multiple geochemical settings”
  • 2012-2013 Center for Dark Energy Biosphere Investigations research grant awarded: “The distribution and activity of marine subsurface Fungi”
  • 2012 Center for Dark Energy Biosphere Investigations travel grant awarded
  • 2011-2013 Center for Dark Energy Biosphere Investigations postdoctoral fellowship:
    “Worldwide exploration of fungal distributions and activities in subseafloor sediment


Research Interests

  • • Anaerobic microbiology
    • Microbial carbon cycling
    • Biogeochemistry
    • Stable isotope probing

Teaching and Mentoring Experience

  • 2017-present Co-director of the young scientist Mentoring Program at LMU Munich (Faculty of Geoscience).
  • 2016-present Lecturer and lab instructor for the Geomicrobiology Masters course in Geobiology and Paleobiology Program (MGAP), at LMU Munich
  • 2016-present Lecturer and field course instructor for the Geobiology undergraduate course, Geoscience Bachelors Program at LMU Munich
  • 2016-present Lecturer and field course instructor for the Marine Geology undergraduate course, Geoscience Bachelors Program at LMU Munich
  • 2016-present Lecturer and lab instructor for module Molecular Methods Masters course in Geobiology and Paleobiology Program (MGAP), at LMU Munich
  • 2016-present Lecturer and lab instructor for the Laboratory Methods Masters course in Geobiology and Paleobiology Program (MGAP), at LMU Munich
  • 2016-present Vice-chair of selection committee for Masters Program in Geobiology and Paleobiology (MGAP), at LMU Munich
  • 2016-present Advisor for more than 20 Bachelors and Master Student theses, four PhDs, and three Postdocs

Professional Activities and Service

Reviewer for funding agencies:

NSF Biological Oceanography (Bio-OCE) Program
German Research Nation Funding Agency (DFG)
Swiss Science National Funding Agency
ERC Horizon 2017 funding program
Swedish National Academy of Sciences
French National Research Agency (ANR) ‘Living Earth’
European Union Marie Curie Postdoctoral Fellowship Program

Reviewer for >20 journals including:

Nature Microbiology
Nature Reviews Microbiology
Science Advances
Marine Chemistry
The ISME Journal
Limnology and Oceanography
Applied and Environmental Microbiology
FEMS Microbiology Letters
FEMS Microbial Ecology
BMC Biology

Editor at the following journals:
The ISME Journal
Environmental Microbiology


H-index (August, 2023): 38 (Google Scholar), 32 (Web of Science)

Helmbrecht V, Weingart M, Klein F, Braun D, Orsi W* (2023) White and green rust chimneys accumulate RNA in a ferruginous chemical garden. Geobiology 21: 758-769.

Weingart M, Chen S, Donat C, Helmbrecht V, Orsi W, Braun D, Alim K (2023) Alkaline vents recreated in two dimensions to study pH gradients, precipitation morphology, and molecular accumulation. Science Advances 9: eadi1884.

Coskun OK, Gomez-Saez GV, Beren M, Ozcan D, Hosgormez H, Einsiedl F, Orsi W* (2023) Carbon metabolism and biogeography of candidate phylum “Candidatus Bipolaricaulota” in geothermal environments of Biga Peninsula, Turkey. Frontiers in Extreme Microbiology 14: 1063139.

Mincer TJ, Bos ER, Zettler ER, Zhao S, Asbun AA, Orsi W, GuzzettaVS, Amaral-Zettler LA (2023) Sargasso Sea Vibrio bacteria: Underexplored potential pathovars in a perturbed habitat. Water Research 242: 120033.

Orsi W* (2023) A rapid method for measuring ATP+ADP+AMP in marine sediment. Environmental Microbiology 2: 1549-1558.

Orsi W and Inagaki F (2023) Decoding geobiological evolution from microbiomes. Science Advances 9: eadg5448.

Orsi W* (2022) Quantitative microbial ecology: future challenges and opportunities. Environmental Microbiology 25: 91-96.

Vuillemin A, Coskun OK, Orsi W (2022) Microbial activities and selection from surface ocean to subseafloor on the Namibian continental shelf. Applied and Environmental Microbiology 10: e0021622.

Vargas S, Leiva L, Eitel M, Curdt F, Rohde S, Arnold C, Nickel M, Schupp P, Orsi W, Adamska M, Wörheide G (2022) Body-plan reorganization in a sponge correlates with microbiome change. Molecular Biology and Evolution 40: msad138.

Michaelis T, Wunderlich A, Coskun OK, Orsi W, Baumann T, Einsiedl F (2022) High resolution vertical biogeochemical profiles in the hyporheic zone reveal insights into microbial methane cycling. Biogeosciences 19: 4551-4569.

Orsi W*, Vuillemin, Coskun OK, Rodriguez P, Oertel Y, Niggemann J, Mohrholz V, Gomes-Saez G (2022) Carbon assimilating fungi from surface ocean to subseafloor revealed by coupled phylogenetic and stable isotope analysis. The ISME Journal 16: 1245-1261.

Coskun OK, Vuillemin A, Schubotz F, Klein F, Sichel SE, Eisenreich W, Orsi W* (2022) Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. The ISME Journal 16: 257-271.

Orsi W*, Magritsch T, Vargas S, Coskun OK, Vuillemin A, Höhna S, Wörheide G, D’Hondt S, Shapiro J, Carini P (2021) Genome evolution in clonal bacterial populations isolated from million-year-old subseafloor sediment. mBio 12: e01150-21.

Garber AI, Ramirez GA, McAllister SM, Orsi W, D’Hondt S (2021) Cryptic metabolisms in anoxic subseafloor sediment. Environmental Microbiology Reports 13: 696-701.

Puzenat V, Escartin J, Martel JE, Barreyre T, Le Moine S, Paraskevi N, Gracias N, Allemand P, Antoniou V, Coskun O, Garcia R, Grandjean P, Jørgensen SL, Magi L, Mandalakis M, Orsi W, Polymenakou P, Schouw A, Vallicrosa G, Vlasopoulos O. (2021) Shallow-water hydrothermalism at Milos (Greece): Nature, distribution, heat fluxes and impact on ecosystems. Marine Geology 438; 106521.

E Capo, C Giguet-Covex, A Rouillard, K Nota, P D Heintzman, A Vuillemin, D Ariztegui, F Arnaud, S Belle, S Bertilsson, C Bigler, R Bindler, AG Brown, CL Clarke, SE Crump, D Debroas, G Englund, GF Ficetola, RE Garner, J Gauthier, I Gregory-Eaves, L Heinecke, U Herzschuh, A Ibrahim, V Kisand, KH Kjær, Y Lammers, J Littlefair, E Messager, ME Monchamp, F Olajos, W Orsi, MW Pedersen, DP Rijal, J Rydberg, T Spanbauer, KR Stoof-Leichsenring, P Taberlet, L Talas, C Thomas, DA Walsh, Y Wang, E Willerslev, A van Woerkom, H H Zimmermann, MJL Coolen, LS Epp, I Domaizon, IG Alsos, L Parducci (2021) Lake sedimentary DNA research on past terrestrial and aquatic biodiversity: Overview and recommendations. Quarternary 4: 6.

Vuillemin A, Kerrigan Z, D’Hondt S, Orsi W (2020) Exploring the abundance, metabolic potential, and gene expression of subseafloor Chloroflexi in million-year-old oxic and anoxic abyssal clay. FEMS Microbiology Ecology 96: fiaa223.

Vuillemin A, Vargas S, Coskun O, Pockalny R, Murray R, Smith DC, D’Hondt S, Orsi W* (2020) Atribacteria reproducing over millions of years in the Atlantic abyssal subseafloor. mBio 11:e01937-20.

Orsi W*, Morard R, Vuillemin A, Eitel M, Wörheide G, Milucka J, Kucera M. (2020) Anaerobic metabolism of Foraminifera thriving below the seafloor. The ISME Journal 14: 2580-2594.

Orsi W*, Vuillemin A, Rodriguez P, Coskun O, Gomez G, Mohrholz V, Lavik G, Ferdelman T
(2020) Metabolic activity analyses demonstrate that Lokiarchaeon exhibits
homoacetogenesis in sulfidic marine sediments. Nature Microbiology 5: 248–255.

Einsiedl F, Wunderlich A, Sebilo M, Coskun ÖK, Orsi W, Mayer B (2020) Biogeochemical evidence of anaerobic methane oxidation and anaerobic ammonium oxidation in a stratified lake using stable isotopes. Biogeosciences 17: 5149–5161.

Orsi W*, Schink B, Buckel W, Martin WF (2020) Physiological limits to life in anoxic subseafloor sediment. FEMS Microbiology Reviews 2: 219-231.

LaRowe DE, Arndt S, Bradley JA, Estes ER, Hoarfrost A, Lang SQ, Lloyd KG, Mahmoudi N, Orsi W, Shah Walter SR, Steen AD, Zhao R (2020) The fate of organic carbon in marine sedements – New insights from recent data and analysis. Earth-Science Reviews 204: 103146.

Girard EB, Kaliwoda M, Schmahl WW, Wörheide G, Orsi W* (2020) Biodegradation of textile waste by marine bacterial communities enhanced by light. Environmental Microbiology Reports 12: 406-418.

Vuillemin A, Wankel SD, Coskun OK, Magritsch T, Vargas S, Estes ER, Spivack AJ, Smith
DC, Pockalny R, Murray RW, D’Hondt S, Orsi W* (2019) Archaea dominate oxic
subseafloor communities over multimillion-year timescales. Science Advances 5:

Coskun O, Özen V, Wankel S, Orsi W* (2019) Quantifying population specific growth in benthic bacterial communities under low oxygen using H218O. The ISME Journal 13,

Ortega-Arbulu AS, Pichler M, Vuillemin A, Orsi W* (2019) Effects of organic matter and low
oxygen on the mycobenthos in a coastal lagoon. Environmental Microbiology 21: 374-

Orsi W* (2018) Ecology and evolution of seafloor and subseafloor microbial communities. Nature Reviews Microbiology 16, 671-683. [Recommended by Faculty of 1000]

Coskun OK, Pichler M, Vargas S, Gilder S, Orsi W* (2018) Linking uncultivated microbial populations with benthic carbon turnover using quantitative stable isotope probing. Applied and Environmental Microbiology 84(18): e01083-18.

Pichler M, Coskun O, Ortega AS, Conci N, Wörheide G, Vargas S, Orsi W* (2018) A 16S rRNA gene sequencing and analysis protocol for the Illumina MiniSeq platform. MicrobiologyOpen e00611.

Vuillemin A, Horn F, Friese A, Winkel M, Alawi M, Wagner D, Henny C, Orsi W, Crowe SA, Kallmeyer J (2018) Metabolic potential of microbial communities from ferruginous sediments. Environmental Microbiology 20, 4297-4313.

Vuillemin A, Ariztegui D, Horn F, Kallmeyer J, Orsi W, the PASADO Science Team (2018) Microbial community composition along a 50,000 year lacustrine sediment sequence. FEMS Microbiology Ecology 94, fiy029.

Kose SH, Grice K, Orsi W, Ballal M, Coolen MJL (2018) Metagenomics of pigmented and cholesterol gallstones: the putative role of bacteria. Scientific Reports 8, 11218.

Giosan L, Orsi W, Coolen M, Wuchter C, Dunlea AG, Thirumalai K, Munoz S, Clift PD, Donnelly JP, Galy V, Fuller DQ (2018) Neoglacial climate anomalies and the Harappan Metamorphosis. Climate of the Past 14, 1669-1686.

More KD, Orsi W, Galy V, Giosan L, He L, Grice K, Coolen MJL (2018) A 43 kyr record of protist communities and their response to oxygen minimum zone variability in the Northeastern Arabian Sea. Earth and Planetary Science Letters 496, 248-256.

Orsi W*, Richards TA, Francis WR (2018) Predicted microbial secretomes and their target substrates in marine sediments. Nature Microbiology 3: 32-37.

Orsi W*, Wilken S, del Campo J, Heger T, James E, Richards TA, Keeling PJ, Worden AZ, Santoro AE (2018) Identifying protist consumers of photosynthetic picoeukaryotes in the surface ocean using stable isotope probing. Environmental Microbiology 20, 815-827

He K, Gilder SA, Orsi W, Zhao X, Petersen N (2017) Constant flux of spatial niche partitioning through high-resolution sampling of magnetotactic bacteria. Applied and Environmental Microbiology 83(20) e01382-17.

Orsi W*, Coolen MJ, Wuchter C, He L, More KD, Irigoien X, Chust G, Johnson C, Hemingway JD, Lee M, Galy V, Giosan L (2017) Climate oscillations reflected in the microbiome of Arabian Sea sediments. Scientific Reports 7: 6040.

Orsi W*, Jørgensen BB, Biddle JF (2016) Transcriptional analysis of sulfate reducing and chemolithoautotrophic sulfur oxidizing bacteria in the deep subseafloor. Environmental Microbiology Reports 8, 452-460.

Orsi W*, Smith JM, Liu S, Liu Z, Sakamoto CM, Wilken S, Poirier C, Richards TA, Keeling PJ, Worden AZ, Santoro AE (2016) Diverse, uncultivated bacteria and archaea underlying the cycling of dissolved protein in the ocean. The ISME Journal 10, 2158-2173. [Recommended by Faculty of 1000]

Klein F, Humphris SE, Guo W, Schubotz F, Schwarzenbach EM, Orsi WD (2015) Fluid mixing and the deep biosphere of a fossil Lost City-type hydrothermal system at the Iberia Margin. PNAS 112, 12036-12041.

Orsi W*, Richards TA, Santoro AE (2015) Cellular maintenance processes potentially underpin the survival of subseafloor fungi over geological timescales. Estuarine Costal and Shelf Science 164: A1-A9.

Orsi W*, Smith JM, Wilcox HM, Swalwell JE, Carini P, Worden AZ, Santoro AE (2015). Ecophysiology of uncultivated marine euryarchaea is linked to particulate organic matter. The ISME Journal 9: 1747-1763.

Coolen MJL** and Orsi W** (2015) The transcriptional response of microbial communities in thawing Alaskan permafrost soils. Frontiers in Microbiology 6:197. **Co-first authors.

Engelhardt T, Orsi W, Jørgensen BB (2015) Viral activities and life-cycles in deep subseafloor sediment. Environmental Microbiology Reports 7: 868-873..

Santoro AE, Dupont CL, Richter RA, Craig MT, Carini P, McIlvin MR, Yang Y, Orsi W, Moran D, Saito MA (2015). Genomic and proteomic characterization of ‘Candidatus Nitrosopelagicus brevis’: an ammonia-oxidizing archaeon from the open ocean. PNAS 114:1173-1178.

Orcutt BN, LaRowe D, Lloyd K, Mills H, Orsi W, Reese BK, Sauvage J, Huber JA, Amend J. (2014) IODP deep biosphere research workshop report – a synthesis of recent investigations, and discussion of new research questions and drilling targets. Scientific Drilling 2:1-6.

Stoeck T, Filker S, Edgcomb V, Orsi W, Yakimov M, Pachiadaki M, Breiner HW, LaCono V, Stock A. (2014) Living at the limits: Evidence for microbial eukaryotes thriving under pressure in deep anoxic, hypersaline habitats. Advances in Ecology doi:10.1155/2014/532687

Orsi W*, Edgcomb V, Christman G, Biddle J. (2013). Gene expression in the deep biosphere. Nature 499: 205-208.
Coolen MJL, Orsi W, Balkema C, Quince C, Harris K, Sylva S, Filipova-Marinova M, Giosan L. (2013). Evolution of the plankton paleome in the Black Sea from the Deglacial to Anthropocene. PNAS 110(21): 8609-14.

Orsi W*, Biddle J, Edgcomb, V. (2013). Deep sequencing of subseafloor eukaryotic rRNA reveals active Fungi across multiple subseafloor provinces. PLoS ONE 8(2): e56335.

Burgaud G, Woehlke S, Redou V, Orsi W, Beaudoin D, Barbier G, Biddle J, Edgcomb V. (2013). Deciphering presence and activity of fungal communities in marine sediments using a model estuarine system. Aquatic Microbial Ecology 70: 45-62.

Stock A, Edgcomb V, Orsi W, Filker S, Breiner HW, Yakimov M, Stoeck T. (2013). Evidence for isolated evolution of deep-sea ciliate communities through geological separation and environmental selection. BMC Microbiology 13:150.

Edgcomb V, Bernhard J, Summons R, Orsi W, Beaudoin D, Visscher P. (2013). Active eukaryotes in microbialites from Highborne Cay, Bahamas, and Hamelin Pool (Shark Bay), Australia. The ISME Journal. 8: 418-429.

Edgcomb V, Orsi W, Biddle J. (2013) Fungi in the marine subsurface; In: Kallmeyer, J. and Wagner, D. (eds.), Microbial life of the Deep Biosphere. (in press) De Gruyter, Berlin.

Orsi W*, Song Y, Hallam S, Edgcomb V. (2012). Effect of oxygen minimum zone formation on communities of marine protists. The ISME Journal 6: 1586-1601.

Orsi W, Edgcomb V, Faria J, Foissner W, Fowle W, Hohmann T, Suarez S, Taylor C, Taylor GT, Vdacny P, Epstein S. (2012). Class Cariacotrichea, a novel ciliate taxon from the anoxic Cariaco Basin, Venezuela; International Journal of Systematic and Evolutionary Microbiology 62: 1425-1433.

Orsi W*, Charvet S, Vd’ačný P, Bernhard JM, Edgcomb V. (2012). Prevalence of partnerships between bacteria and ciliates in oxygen-depleted marine water columns. Frontiers in Extreme Microbiology 3: 341.

Vdacny P, Bourland W, Orsi W, Epstein S, Foissner W. (2012). Genealogical analyses of multiple loci of litostomatean ciliates (Protista, Ciliophora, Litostomatea). Molecular Phylogenetics and Evolution 65(2): 397-411.

Filker S, Stock A, Breiner H W, Edgcomb V, Orsi W, Yakimov M, Stoeck T. (2012). Environmental selection of protistan plankton communities in hypersaline anoxic deep-sea basins, Eastern Mediterranean Sea. MicrobiologyOpen 2(1): 54-63.

Orsi W and Edgcomb V. (2012). Microbial Eukaryotes in Oxygen Minimum Zones; In: Seckbach, J., Oren, A., and Stan-Lotter, H. (eds.), Polyextremophiles – Organisms living under multiple stress; Springer, Dordrecht.

Edgcomb V and Orsi W. (2012). Microbial Eukaryotes in Hypersaline Anoxic Deep Sea Basins; In: Seckbach, J., Oren, A., and Stan-Lotter, H. (eds.), Polyextremophiles – Organisms living under multiple stress; Springer, Dordrecht.

Orsi W, Edgcomb V, Jeon S O, Leslin C, Bunge J, Taylor G T, Varela R, Epstein S. (2011). Protistan microbial observatory in the Cariaco Basin, Caribbean. Part II. Habitat specialization. The ISME Journal 5:1344-1356.

Edgcomb V, Orsi W, Bunge J, Jeon S O, Leslin C, Christen R, Holder M, Taylor G T, Suarez P, Varela R, Epstein S. (2011). Protistan microbial observatory in the Cariaco Basin, Caribbean. Part I. Pyrosequencing vs. Sanger insights into species richness. The ISME Journal 5: 1357-1373.

Edgcomb V, Orsi W, Taylor G T, Vd’ačný P, Taylor C, Suarez P, Epstein S. (2011). Commentary: Accessing marine protists from the anoxic Cariaco Basin. The ISME Journal 5: 1237-1241.

Edgcomb V, Orsi W, Breiner HW, Stock A, Filkner S, Yakimov M, Stoeck T. (2011). Eastern Mediterranean deep hypersaline anoxic lakes: novel active kinetoplastids associated with halocline habitats. Deep–Sea Research I 58 (10): 1040-1048.

Vd’ačný P, Bourland W, Orsi W, Epstein S, Foissner W. (2011). Phylogeny and classification of the Litostomatea (Protista, Ciliophora), with an emphasis on free-living taxa and the 18S rRNA gene. Molecular Phylogenetics and Evolution 59 (2): 510-522.

Vd’ačný P, Orsi W, Bourland W, Satoshi S, Epstein S, Foissner W. (2011). Morphological and molecular phylogeny of Dileptids: resolution at the base of the class Litostomatea (Ciliophora, Intramacronucleata). European Journal of Protistology 47 (4): 295-313.

Vd’ačný P, Orsi W, Foissner W. (2010). Molecular and morphological evidence for a sister group relationship of the classes Armophorea and Litostomatea (Ciliophora, Intramacronucleata, Lamellicorticata infraphyl. nov.), with an account on basal haptorid litostomateans. European Journal of Protistology 46 (4): 298-309.

Edgcomb V, Orsi W, Leslin C, Epstein SS, Bunge J, Jeon S, Yakimov MM, Behnke A, Stoeck T. (2009). Protistan community patterns within the brine and halocline of deep hypersaline anoxic basins in the eastern Mediterranean Sea. Extremophiles 13 (1): 151-167.

Stoeck T, Behnke A, Christen R, Amaral-Zettler L, Rodriguez-Mora MJ, Chistoserdov A, Orsi W, Edgcomb VP. (2009). Massively parallel tag sequencing reveals the complexity of anaerobic marine protistan communities. BMC Biology 7:72.