Julie Cosmidis

Julie Cosmidis

Associate Professor of Geobiology

Microbial biomineralization is one of the mechanisms by which microorganisms impact their environment, and it is increasingly regarded as an important driving force in the chemical, geological and biological evolution of Earth throughout its history. My research focuses on deciphering the molecular mechanisms involved in microbial biomineralization, understanding its impact on past and present environments, and using it as a tool for tracing microbial activity in the geological record. I also work on developing industrial applications for biomaterials and microbial processes.

Please click on  this link to learn about potential DPhil projects. Prospective students are invited to contact me before submitting an application.

  • McMahon S, Cosmidis J, False Biosignatures on Mars: Anticipating Ambiguity, Journal of the Geological Society (2021)
  • 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)
  • 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)
  • 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)