Julie Cosmidis

Julie Cosmidis

Associate Professor of Geobiology

Microbe-Mineral Lab

We are currently recruiting new DPhil students. Please get in touch before applying if you are interested in these positions.

Biominerals are a fascinating testimony of life’s capacity to shape the inorganic world. Through the formation of minerals, bacteria participate in fluxes of most elements at the surface of the Earth, having profound impacts on biogeochemical cycles. Minerals formed by bacteria often possess unique properties such as non-crystallographic morphologies, thermodynamically unstable structures, out-of-equilibrium chemical compositions, and intimate association with organic matrices. These properties strongly influence the stability, reactivity, and bioavailability of biominerals in the environment, and hence determine their roles in biogeochemical cycles. Moreover, due to these specific properties, microbial biominerals can be used as biosignatures for the search of life on early Earth, and have been proposed as targets for astrobiological exploration on other planets. Our laboratory works on deciphering the molecular-level mechanisms of microbial biomineralization, with a focus on the organic-mineral interactions that confer biominerals their special properties.

In addition to their important role in biogeochemical cycles and value in palaeobiological investigations, microbial “biomineral factories” may be used to produce high-value materials for diverse technological applications. We are working on developing novel microbial processes for the bioproduction of high-value minerals and materials. Through these efforts, we work to make microbial biomineralization a critical tool to meet our needs of mineral materials (e.g. for energy storage or construction) without compromising Earth’s resources, enabling us to transition from a petrochemical industry to a more sustainable model based on bio-manufacturing.

Current lab members:

  •  Shuo Wang – NERC DTP DPhil student
  • Sharmin Yousuf Rikta – DPhil student
  • Luke williams – Lab manager


BioFacts project (ERC Starting grant / UKRI)

Starting April 2024, the 5-year project BioFacts will combine high-throughput Raman spectromicroscopy and molecular biology approaches to uncover new biological mechanisms controlling microbial biomineralization. Please get in touch if you are interested in joining the project as a postdoctoral researcher or DPhil student.

  • Cosmidis J, Will tomorrow’s mineral materials be grown?, Microbial Biotechnology (2023)
  • Cosmidis J, Benzerara K, Why do microbes make minerals?, Comptes Rendus. Géoscience (2022)
  • McMahon S, Cosmidis J, False Biosignatures on Mars: Anticipating Ambiguity, Journal of the Geological Society (2022)
  • Cron B, Macalady J. L., Cosmidis J, Organic stabilization of extracellular elemental sulfur in a Sulfurovum-rich biofilm: a new role for EPS? Frontiers in Microbiology (2021)
  • Nims C, Lafond J, Alleon J, Templeton A, Cosmidis J, Organic biomorphs may be better preserved than microorganisms in early Earth sediments, Geology (2021)
  • Stanton C, Cosmidis J, Kump L, A re-examination of the mechanism of whiting events: A new role for diatoms in Fayetteville Green Lake (New York, USA), EarthArXiv (2021)
  • Cron B, Henri P, Chan C, Macalady J, Cosmidis J, Elemental sulfur formation by Sulfuricurvum kujiense is mediated by extracellular organic compounds, Frontiers in Microbiology, 10, 2710 (2019)
  • Nims C, Cron B, Wetherington M, Macalady J, Cosmidis J, Low frequency Raman Spectroscopy for micron-scale and in vivo characterization of elemental sulfur in microbial samples, Nature Scientific Reports, 9, 7971 (2019)
  • Cosmidis J, Nims C, Diercks D, Templeton A, Formation and stabilization of elemental sulfur through organomineralization, Geochimica et Cosmochimica Acta, 247, 59–82 (2019)
  • Stanton C, Barnes B, Kump Lee R., Cosmidis J, A re-examination of the mechanism of whiting events: A new role for diatoms in Fayetteville Green Lake (New York, USA), Geobiology (2023)
  • Lau G L, Trivedi C B,  Grasby S E, Spear J R, Cosmidis J, Templeton A S, Sulfur-and Iron-Rich Mineralogical Features Preserved in Permafrost in the Canadian High Arctic: Analogs for the Astrobiological Exploration of Mars, Frontiers in Astronomy and Space Sciences (2022)
  • Cosmidis J, O’Reilly S,  Ellison E T,  Crispin K L, Diercks D, Templeton A S, Carbonate polymorphism controlled by microbial iron redox dynamics at a natural CO2 leakage site (Crystal Geyser, Utah), EarthArXiv (2021)
  • Bralower T, Cosmidis J, Fantle M.S., Lowery C.M. et al., The Habitat of the Nascent Chicxulub Crater, AGU Advances, 1, e2020AV000208 (2020)
  • Bralower T, Cosmidis J, Heaney PJ, Kump LR, et al., Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact, Earth and Planetary Science Letters, 548, 116476 (2020)
  • Picard A, Gartman A, Cosmidis J, Obst M, Vidoudez C, Clarke DR, Girgis PR, Authigenic iron sulfide minerals preserve organic carbon in anoxic environments, Chemical Geology, 530, 119343 (2019)
  • Johnson J E, Muhling J R, Cosmidis J, Rasmussen B, Templeton A S, Low-Fe(III) Greenalite Was a Primary Mineral from Neoarchean Oceans, Geophysical Research Letters (2018)
  • Skouri-Panet  F, Benzerara K, Cosmidis J,Férard C, Caumes G, De Luca G, Heuilin T, Duprat E, In Vitro and in Silico Evidence of Phosphatase Diversity in the Biomineralizing Bacterium Ramlibacter tataouinensis, Frontiers in Microbiology,8, 2592 (2018)
  • Lau G, Cosmidis J, Grasby S, Trivedi C, Spear J, Templeton A, Low-temperature formation and stabilization of rare allotropes of cyclooctasulfur (β-S8 and γ-S8) in the presence of organic carbon at a sulfur-rich glacial site in the Canadian High Arctic, Geochimica et Cosmochimica Acta, 200, 218–231 (2017)
  • Cosmidis J, Templeton A, Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments, Nature Communications, 7, 12812 (2016)
  • Li J, Margaret-Oliver I, Cam N, Boudier T, Blondeau M, Leroy E, Cosmidis J, Skouri-Panet F, Guigner J-M, Ferard C, Poinsot M, Moreira D, Lopez-Garcia P, Cassier-Chauvat C, Chauvat F, Benzerara K, Biomineralization patterns of intracellular carbonatogenesis in cyanobacteria: Molecular hypotheses, Minerals, 6:1, 10 (2016)
  • Cosmidis J, Benzerara K, Guyot F, Skouri-Panet F, Duprat E, Férard C, Guigner J-M, Babonneau F, Coehlo C, Calcium-phosphate biomineralization induced by alkaline phosphatase activity in Escherichia coli: localization, kinetics and potential signatures in the fossil record, Frontiers in Earth Science, 3, 84 (2015)
  • Jain R, Seder-Colomina M, Jordan N, Dessi P, Cosmidis J, van Hullebusch E, Weiss S, Farges F, Lens P, Entrapped elemental selenium nanoparticles affect physicochemical properties of selenium fed activated sludge, Journal of hazardous materials, 295, 193–200 (2015)
  • Zatoń M, Niedźwiedzki G, Marynowski L, Benzerara K, Pott C, Cosmidis J, Krzykawski T, Filipiak P, Coprolites of Late Triassic carnivorous vertebrates from Poland: An integrative approach, Palaeogeography Palaeoclimatology Palaeoecology, 430, 21–46 (2015)
  • Cosmidis J, Benzerara K, Nassif N, Tyliszczak T, Bourdelle F, Characterization of Ca-phosphate biological materials by Scanning Transmission X-ray Microscopy (STXM) at the Ca L2,3-, P L2,3– and C K-edges, Acta Biomaterialia, 12, 260–269 (2015)
  • Li J, Bernard S, Benzerara K, Beyssac O, Allard T, Cosmidis J, Moussou J, Impact of biomineralization on the preservation of microorganisms during fossilization: An experimental perspective, Earth and Planetary Science Letters, 400, 113–122 (2014)
  • Benzerara K, Skouri-Panet F, Li J, Ferard C, Gugger  M,  Laurent T, Couradeau E,  Ragon M, Cosmidis J, Menguy N, Margaret-Oliver I, Tavera R, Lopez-Garcia P, Moreira D, Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria, Proceedings of the National Academy of Sciences, 111, 10933–10938 (2014).
  • Cosmidis J, Benzerara K, Morin G, Busigny V, Jézéquel D, et al., Biomineralization of iron phosphates in the anoxic water column of Lake Pavin (Massif Central, France), Geochemica et Cosmochemica Acta, 126:78–96 (2014).
  • Cosmidis J, Benzerara K, Menguy N, Arning E, Microscopy evidence of bacterial microfossils in phosphorite crusts of the Peruvian shelf: implications for phosphogenesis mechanisms, Chemical Geology, 359, 10–22 (2013)
  • Baumgartner J, Morin G, Menguy N, Perez Gonzalez T, Widdrat M, Cosmidis J, Faivre D, Magnetotactic bacteria form magnetite from a phosphate-rich ferric hydroxide via nanometric ferric (hydr)oxide intermediates, Proceedings of the National Academy of Sciences, 110, 14883–14888 (2013)
  • Bourdelle F, Benzerara K, Beyssac O, Cosmidis J, Neuville D R, Brown G E Jr., Paineau E, Quantification of the ferric/ferrous iron ratio in silicates by scanning transmission X-ray microscopy at the Fe L2,3 edges, Contributions to Mineralogy and Petrology, 166, 423–434 (2013)
  • Cosmidis J, Benzerara K, Gheerbrant E, Estève I, Bouya B and Amaghzaz M, Nanometer scale characterization of exceptionally preserved bacterial fossils in Paleocene phosphorites from Ouled Abdoun (Morocco), Geobiology, 11:2, 139–153 (2013)

Book Chapters

  • Busigny V, Jézéquel D, Cosmidis J, Viollier E, Benzerara K, Planavsky N, Albéric P, Lebeau O, Sarazin G and Michard G, The Iron Wheel in Lac Pavin: Interaction with Phosphorus Cycle. In: Lake Pavin: History, biogeochemistry, and sedimentology of a deep meromictic maar lake, T Sime-Ngando, P Boivin, E Chapron, D Jezequel, and M Meybeck (eds.), Springer International Publishing, pp. 205–220 (2016)
  • Cosmidis J, Benzerara K, Soft X-ray Scanning Transmission Micro-Spectroscopy, In: Biomineralization Sourcebook: Characterization of Biominerals and Biomimetic Materials, Laurie Gower and Elaine DiMasi (eds.), Taylor and Francis, London, pp. 115–133 (2014)


  • Cosmidis J and Templeton A, “Sulfur-Carbon Tubes and/or Spheres, and Methods of Making Same”, US Patent No. 10790500 (2020)