My research interests include:
- The search for and study of ancient biosignatures, including microfossils, organic geochemistry, and isotopic signatures, with emphasis on those of the Archean (the first 2 billion years of Earth history)
- The search for past or present signature of extraterrestrial life, especially on Mars
- Understanding the organic geochemical alteration of microfossils and inorganic aspects of fossilization (e.g., permineralization)
Current Projects
From my lab
Searching for oxidizing oases in the Paleoarchean Moodies Group, Barberton Greenstone Belt, South Africa through elemental, organic, and isotope geochemistry (Brianna Orrill's NASA-funded project with Mike Tice of Texas A&M University)
Searching for evidence of ancient life in Jezero crater on Mars with the Mars 2020 mission (funded through the Mars 2020 Returned Sample Science Participating Scientist program/Mars 2020 Science Office)
Study of the microbial composition and diversity in microbialites from a 2.5-billion-year-old carbonate platform from the Kaapvaal craton of South Africa, and thermal alteration of ancient sedimentary rocks as measured by Raman spectroscopy in various lithologies (Andrea Corpolongo's and Sam Hall's NSF-funded Ph.D. projects with collaborators Bertus Smith and Nicolas Beukes (deceased), U. of Johannesburg)
Developing a laboratory for in situ morphological and geochemical analyses of microbial fossils and traces in rocks from the ancient Earth and Mars (Andrea Corpolongo's UC Office of Research funded postdoctoral work)
Carbon and sulfur isotope compositions and ecological interpretations of 2.5-billion-year-old microfossils from South Africa (collaborators: Jeff Osterhout, UCLA; Ken Williford, JPL; John Valley, UW-Madison)
As a collaborator
Biofilm textures and morphologies from Yellowstone National Park (with Jeff Havig and Trinity Hamilton, University of Minnesota)
Identifying inclusions in garnets in Paleozoic metamorphic rocks from New England (collaborator: Craig Dietsch, UC Geology)
From my lab
Searching for oxidizing oases in the Paleoarchean Moodies Group, Barberton Greenstone Belt, South Africa through elemental, organic, and isotope geochemistry (Brianna Orrill's NASA-funded project with Mike Tice of Texas A&M University)
Searching for evidence of ancient life in Jezero crater on Mars with the Mars 2020 mission (funded through the Mars 2020 Returned Sample Science Participating Scientist program/Mars 2020 Science Office)
Study of the microbial composition and diversity in microbialites from a 2.5-billion-year-old carbonate platform from the Kaapvaal craton of South Africa, and thermal alteration of ancient sedimentary rocks as measured by Raman spectroscopy in various lithologies (Andrea Corpolongo's and Sam Hall's NSF-funded Ph.D. projects with collaborators Bertus Smith and Nicolas Beukes (deceased), U. of Johannesburg)
Developing a laboratory for in situ morphological and geochemical analyses of microbial fossils and traces in rocks from the ancient Earth and Mars (Andrea Corpolongo's UC Office of Research funded postdoctoral work)
Carbon and sulfur isotope compositions and ecological interpretations of 2.5-billion-year-old microfossils from South Africa (collaborators: Jeff Osterhout, UCLA; Ken Williford, JPL; John Valley, UW-Madison)
As a collaborator
Biofilm textures and morphologies from Yellowstone National Park (with Jeff Havig and Trinity Hamilton, University of Minnesota)
Identifying inclusions in garnets in Paleozoic metamorphic rocks from New England (collaborator: Craig Dietsch, UC Geology)
Publications (*denotes a student led paper)
Hausrath EM, Sullivan R, Goreva Y, Zorzano M-P, Vaughan A, Cousin A, Siljeström S, Sharma S, Shumway A, Kizovski T, VanBommel S, Tice M, Knight A, Martinez G, Vicente-Retortillo A, Mandon L, Adcock CT, Madariaga JM, Población I, Johnson JR, Lasue J, Gasnault O, Randazzo N, Cardarelli EL, Kronyak R, Bechtold A, Paar G, Udry A, Forni O, Bedford CC, Carman NA, Bell JF III, Benison K, Bosak T, Brown A, Broz A, Calef F, Clark BC, Cloutis E, Czaja AD, Fornaro T, Fouchet T, Golombek M, Gómez F, Herd CDK, Herkenhoff K, Jakubek RS, Jandura L, Martinez-Frias J, Mayhew LE, Meslin P-Y, Newman CE, Núñez JI, Poulet F, Royer C, Russell P, Sephton MA, Sharma SK, Shuster D, Simon JI, Tirona I, Wiens RC, Weiss BP, Williams AJ, Williford K, Wolf ZU, and the Regolith Working Group (Accepted) Collection and in situ analyses of regolith samples by the Mars 2020 rover: Implications for their formation and alteration history. Journal of Geophysical Research: Planets.
Bosak T, Shuster DL, Scheller E, Siljeström S, Zawaski M, Mandon L, Simon JI, Weiss BP, Stack KM, Mansbach EN, Treiman A, Benison K, Brown A, Czaja AD, Farley K, Hausrath EM, Herd CDK, Johnson J, Mayhew LE, Minitti ME, Williford K, Wogsland BV, Zorzano MP, Hurowitz J, Hand K, Allwood A, Amundsen HEF, Bell J, Benzerara K, Beyssac O, Cable M, Calef F, Caravaca G, Calef FJ III, Catling D, Clavé E, Cloutis E, Cohen BA, Cousin A, Flannery D, Forni O, Fouchet T, Gibbons E, Gómez F, Gupta S, Hickman-Lewis K, Kalucha H, Lopes-Reyes G, Maki J, Maurice S, Randazzo N, Rice J, Sephton M, Sharma S, Steele A, Tate C, Uckert K, Udry A, and Wiens R. (2024) Astrobiological potential of rocks acquired by the Perseverance rover at a sedimentary fan front in Jezero crater, Mars. AGU Advances, 5, e2024AV001241. https://doi.org/10.1029/2024AV001241
Phua YY, Ehlmann BL, Siljeström S, Czaja AD, Beck P, Connell S, Wiens RC, Jakubek RS, Williams RME, Zorzano M-P, Minitti ME, Pascuzzo AC, Hand KP, Bhartia R, Kah LC, Mandon L, Razzell Hollis J, Scheller EL, Sharma S, Steele A, Uckert K, Williford KH, and Yanchilina AG (2024) Characterizing hydration carrier phases in altered rocks of Jezero Crater fan and floor geologic units with SHERLOC on Mars 2020 Journal of Geophysical Research: Planets, 129, e2023JE008251. https://doi.org/10.1029/2023JE008251
Zorzano M-P, Martínez G, Polkko J, Tamppari LK, Newman C, Savijärvi H, Goreva Y, Viúdez‑Moreiras D, Bertrand T, Smith M, Hausrath EM, Siljeström S, Benison K, Bosak T, Czaja AD, Debaille V, Herd CDK, Mayhew L, Sephton MA, Shuster D, Simon JI, Weiss B, Randazzo N, Mandon L, Brown A, Hecht MH, and Martínez‑Frías J. (2024) Present-day thermal and water activity environment of the Mars Sample Return collection. Scientific Reports 14, 7175. https://doi.org/10.1038/s41598-024-57458-4
Benison, K. C., Gill, K. K., Sharma, S., Siljeström, S., Zawaski, M., Bosak, T., Broz A, Clark BC, Cloutis E, Czaja AD, Flannery D, Fornaro T, Gómez F, Hand K, Herd CDK, Johnson JR, Madariaga JM, Madsen MB, Martinez-Frías J, Nachon M, Núñez JI, Pedersen DAK, Randazzo N, Shuster DL, Simon J, Steele A, Tate C, Treiman A, Uckert K, Williams AJ, and Yanchilina A. (2024) Depositional and diagenetic sulfates of Hogwallow Flats and Yori Pass, Jezero crater: Evaluating preservation potential of environmental indicators and possible biosignatures from past Martian surface waters and groundwaters. Journal of Geophysical Research: Planets, 129 (2), e2023JE008155. https://doi.org/10.1029/2023JE008155
Jakubek RS, Bhartia R, Uckert K, Asher SA, Czaja AD, Fries MD, Hand K, Haney NC, Razzell Hollis J, Minitti M, Sharma SK, Sharma S, and Siljeström S. (2023) Calibration of Raman Bandwidths on the SHERLOC Deep UV Raman and Fluorescence Instrument aboard the Perseverance Rover. Applied Spectroscopy. https://doi.org/10.1177/00037028231210885
#Siljeström S, #Czaja AD, *Corpolongo A, Berger EL, Li AY, Cardarelli E, Abbey W, Asher SA, Beegle LW, Benison KC, Bhartia R, Bleefeld BL, Burton AS, Bykov SV, Clark B, DeFlores L, Ehlmann BL, Fornaro T, Fox A, Gómez F, Hand K, Haney NC, Hickman-Lewis K, Hug WF, Imbeah S, Jakubek RS, Kah LC, Kivrak L, Lee C, Martínez-Frías J, McCubbin FM, Minitti M, Moore K, Morris RV, Núñez JI, Osterhout JT, Phua YY, Randazzo N, Razzell Hollis J, Rodriguez C, Roppel R, Scheller EL, Sephton ME, Sharma SK, Sharma S, Steadman K, Steele A, Tice M, Uckert K, VanBommel S, Williams AJ, Williford KH, Winchell K, Wu M, Yanchilina A, and Zorzano M-P. (2024) Evidence of Sulfate-Rich Fluid Alteration in Jezero Crater Floor, Mars. Journal of Geophysical Research: Planets 129 (1), e2023JE007989. https://doi.org/10.1029/2023JE007989 (#Contributed equally as co-lead authors)
*Corpolongo A, Jakubek RS, Abbey W, Asher SA, Baker D, Beegle LW, Berger EL, Bhartia R, Brown AJ, Burton AS, Bykov SV, Cardarelli E, Cloutis EA, Conrad P, Czaja AD, DeFlores L, Flannery D, Fornaro T, Fries M, Haney NC, Hickman-Lewis K, Kah L, Lee C, McCubbin FM, Minitti M, Morris RV, Hollis JR, Roppel R, Scheller EL, Sharma S, Shkoylar S, Siljeström S, Steadman K, Steele A, Uckert K, Wogsland BV, and Yanchilina A. (2023) SHERLOC Raman mineral detections of the Mars 2020 Crater Floor Campaign, Journal of Geophysical Research: Planets 128 (3), e2022JE007455. https://doi.org/10.1029/2022JE007455
Sharma S, Roppel RD, Murphy AE, Beegle LW, Bhartia R, Steele A, Razzell Hollis J, Siljeström S, McCubbin FM, Asher SA, Abbey WJ, Allwood AC, Berger EL, Bleefeld BL, Burton AS, Bykov SV, Cardarelli EL, Conrad PG, Corpolongo A, Czaja AD, DeFlores LP, Edgett K, Farley KA, Fornaro T, Fox AC, Fries MD, Harker D, Hickman-Lewis K, Huggett J, Imbeah S, Jakubek RS, Kah LC, Lee C, Liu Y, Magee A, Minitti M, Moore KR, Pascuzzo A, Sanchez-Vahamonde CR, Scheller EL, Shkolyar S, Stack KM, Steadman K, Tuite M, Uckert K, Werynski A, Wiens RC, Williams AJ, Winchell K, Kennedy MR, and Yanchilina A (2023) Diverse organic-mineral associations in Jezero crater, Mars. Nature, 619: 724–732. https://doi.org/10.1038/s41586-023-06143-z
Simon JI, Hickman-Lewis K, Cohen BA, Mayhew LE, Shuster DL, Debaille V, Hausrath EM, Weiss BP, Bosak T, Zorzano M-P, Amundsen HEF, Beegle LW, Bell JF III, Benison KC, Berger EL, Beyssac O, Brown AJ, Calef F, Casademont TM, Clark B, Clavé E, Crumpler L, Czaja AD, Fairén AG, Farley KA, Flannery DT, Fornaro T, Forni O, Gómez F, Goreva Y, Gorin A, Hand KP, Hamran S-E, Henneke J, Herd CDK, Horgan BNH, Johnson JR, Joseph J, Kronyak RE, Madariaga JM, Maki JN, Mandon L, McCubbin FM, McLennan SM, Moeller RC, Newman CE, Núñez JI, Pascuzzo AC, Pedersen DA, Poggiali G, Pinet P, Quantin-Nataf C, Rice M, Rice JW Jr., Royer C, Schmidt M, Sephton M, Sharma S, Siljeström S, Stack KM, Steele A, Sun VM, Udry A, VanBommel S, Wadhwa M, Wiens RC, Williams AJ, and Williford KH. (2023) Samples Collected from the Floor of Jezero Crater with the Mars 2020 Perseverance Rover, Journal of Geophysical Research: Planets 128, e2022JE007474. https://doi.org/10.1029/2022JE007474
Sun VZ, Hand KP, Stack KM, Farley KA, Simon JI, Newman C, Sharma S, Liu Y, Wiens RC, Williams AJ, Tosca N, Alwmark S, Beyssac O, Brown A, Calef F, Cardarelli EL, Clavé E, Cohen B, Corpolongo A, Czaja AD, Del Sesto T, Fairen A, Fornaro T, Fouchet T, Garczynski B, Gupta S, Herd CDK, Hickman-Lewis K, Horgan B, Johnson J, Kinch K, Kizovski T, Kronyak R, Lange R, Mandon L, Milkovich S, Moeller RC, Núñez J, Paar G, Pyrzak G, Quantin-Nataf C, Shuster DL, Siljeström S, Steele A, Tice M, Toupet O, Udry A, Vaughan A, and Wogsland B. (2023) Overview and Results from the Mars 2020 Perseverance Rover’s First Science Campaign on the Jezero Crater Floor. Journal of Geophysical Research: Planets 128, e2022JE007613. https://doi.org/10.1029/2022JE007613
Tingle KE, Porter SM, Raven MR, Czaja AD, Webb SM, and Bloeser B (2023) Organic preservation of vase-shaped microfossils from the late Tonian Chuar Group, Grand Canyon, Arizona, USA. Geobiology, 00, 1–20. https://doi.org/10.1111/gbi.12544
Lima-Zaloumis J, Neubeck A, Ivarsson M, Bose M, Greenberger R, Templeton AS, Czaja AD, Kelemen P, and Edvinsson T (2022) Microbial biosignature preservation in carbonated serpentine from the Samail Ophiolite, Oman. Nature Communications Earth and Environment, 3(231). https://doi.org/10.1038/s43247-022-00551-1
*Osterhout JT, Schopf JW, Kudryavtsev AB, Czaja AD, and Williford KH (2022) Deep-UV Raman spectroscopy of carbonaceous Precambrian microfossils: Insights into the search for past life on Mars. Astrobiology, 22(10): 1239-1254. https://doi.org/10.1089/ast.2021.0135
Farley KA, Stack KM, Shuster DL, Horgan BHN, Hurowitz JA, and 110 coauthors (2022) Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars. Science, 377(6614): https://doi.org/10.1126/science.abo2196
Johnson CM, Zheng XY, Djokic T, Van Kranendonk MJ, Czaja AD, Roden EE, and Beard BL (2022) Early Archean biogeochemical iron cycling and nutrient availability: New insights from a 3.5 Ga land-sea transition, Earth-Science Reviews, 228: 103992. https://doi.org/10.1016/j.earscirev.2022.103992.
Hackley PC, Kus J, Mendonça Filho JG, Czaja AD, Borrego AG, Životić D, Valentine BJ, and Hatcherian JJ (2022) Characterization of bituminite in Kimmeridge Clay by confocal laser scanning and atomic force microscopy. International Journal of Coal Geology, 251: 103927. https://doi.org/10.1016/j.coal.2022.103927. link to paper
Riedman LA, Porter SM, and Czaja AD (2021) Phosphatic scales in vase shaped microfossil assemblages from Death Valley, Grand Canyon, Tasmania and Svalbard. Geobiology. https://doi.org/10.1111/gbi.12439 PDF
*Gangidine A, Walter MR, Havig JR, Jones C, Sturmer DM, and Czaja AD. (2021) Trace elements in ancient microfossils as a biosignature for Earth and Mars. Life, 11(2): 142. https://doi.org/10.3390/life11020142 PDF
Gan T, Luo T, Pang K, Zhou C, Zhou G, Wan B, Li G, Yi Q, Czaja AD, and Xiao S. (2021) Cryptic terrestrial fungus-like fossils of the early Ediacaran Period. Nature Communications, 12: Article number 641. https://doi.org/10.1038/s41467-021-20975-1 PDF
Hegna TA, Czaja AD, and Rogers DC (2020) Raman spectroscopic analysis of the composition of the clam-shrimp carapace (Branchiopoda: Laevicaudata, Spinicaudata, Cyclestherida): a dual calcium phosphate–calcium carbonate composition. Journal of Crustacean Biology 1–5. https://doi.org/10.1093/jcbiol/ruaa078 PDF
Peng X, Guo Z, Du M, Czaja AD, Papineau D, Chen S, Xu H, Li J, Ta K, Bai S, and Dasgupta S (2020) Past endolithic life in metamorphic ocean crust. Geochemical Perspective Letters 14, 14–19 https://doi.org/10.7185/geochemlet.2017 PDF
Smith AJB, Beukes NJ, Gutzmer J, Johnson CM, Czaja AD, Nhleko N, de Beer F, Hoffman JW, and Awramik SM (2020) Life on a Mesoarchean marine shelf: insights from the world’s oldest known granular iron formation. Scientific Reports, 10, 10519. https://doi.org/10.1038/s41598-020-66805-0 PDF
*Gangidine A, Havig JR, Hannon JS, and Czaja AD (2020) Silica precipitation in a wet-dry cycling hot spring simulation chamber. Life, 10(3), https://doi.org/10.3390/life10010003 PDF
*Gangidine A, Havig JR, Fike DA, Jones C, Hamilton TL, and Czaja AD (2020) Trace element concentrations in hydrothermal silica deposits as a potential biosignature. Astrobiology, 20(3): 1–12. PDF
*Osterhout JT, Czaja AD, Fralick PW, and Bartley JK (2019) Preservation of carbon isotopes in kerogen from thermally altered Mesoproterozoic lacustrine microbialites. Canadian Journal of Earth Science, 56: 1017–1026, dx.doi.org/10.1139/cjes-2018-0309. PDF
Manning-Berg AR, Wood RS, Williford KH, Czaja AD, and Kah LC (2019) The taphonomy of Proterozoic microbial mats and implications for early diagenetic silicification, Geosciences, 9, 40, doi:10.3390/geosciences9010040. link to paper
Beaty DW, et al. (70 co-authors) (2019), The potential science and engineering value of samples delivered to Earth by Mars sample return, Meteoritics & Planetary Science, 54(S1): S3–S152, doi: 10.1111/maps.13242. PDF
Czaja AD, Johnson CM, Beard BL, and Van Kranendonk MJ (2018) A multistage origin for Neoarchean layered hematite-magnetite BIF from the Weld Range, Yilgarn Craton, Western Australia. Chemical Geology, 488: 125–137. link to paper
Muscente, AD, Czaja, AD, Tuggle, J, Winkler, C, and Xiao, S (2018) Manganese oxides resembling microbial fabrics and their implications for recognizing inorganically preserved microfossils. Astrobiology.
Vrazo MB, Diefendorf AF, Crowley BE, and Czaja AD (2018) Late Cretaceous marine arthropods relied on terrestrial organic matter as a food source: geochemical evidence from the Coon Creek lagerstätte in the Mississippian embayment. Geobiology. PDF
Guo Z, Czaja AD, Chen S, Ta K, and Peng X (2018) Cellular taphonomy of well-preserved Gaoyuzhuang microfossils: a window into the preservation of ancient cyanobacteria. Precambrian Research, 304: 88–89. PDF
Muscente AD, Czaja AD, Riedman LA, and Colleary C (2017) Organic Matter in Fossils. In Encyclopedia of Geochemistry, White WM, Ed. Springer International Publishing. PDF
Kang J, Czaja AD, and Guliants VV (2017) Carbon dioxide as feedstock in selective oxidation of propane. European Journal of Inorganic Chemistry. 2017(40): 4757–4762 PDF
Smith AJB, Beukes NJ, Gutzmer J, Czaja AD, Johnson CM, and Nhleko N (2017) Oncoidal granular iron formation in the Mesoarchaean Pongola Supergroup, southern Africa: Textural and geochemical evidence for biological activity during iron deposition. Geobiology, 15: 731–749. PDF
Czaja AD, Beukes NJ, and Osterhout JT (2016) Sulfur-oxidizing bacteria prior to the Great Oxidation Event from the 2.52 Ga Gamohaan Formation of South Africa. Geology, 44(12): 983–986. PDF Suppl File Suppl video A Suppl Video B Suppl Video C
d'Abzac F-X, Czaja AD, Beard, BL, Schauer JJ, and Johnson CM (2014) Iron distribution in size-resolved aerosols generated by UV-femtosecond laser ablation: Influence of cell geometry and implications for in situ isotopic determination by LA-MC-ICP-MS. Geostandards and Geoanalytical Research, 38(3): 293–309. PDF
Wilmeth DT, Dornbos SQ, Isbell JL, and Czaja AD (2014) Putative domal microbial structures in fluvial siliciclastic facies of the Mesoproterozoic (1.09 Ga) Copper Harbor Conglomerate, Upper Peninsula of Michigan, USA. Geobiology, 12: 99–108. PDF
d'Abzac F-X, Beard BL, Czaja AD, Konishi H, Schauer J, and Johnson CM (2013) Iron isotope composition of particles produced by UV-femtosecond laser ablation of natural oxides, sulfides, and carbonates. Analytical Chemistry, 85: 11885–11892. PDF
Li W, Czaja AD, Van Kranendonk MJ, Beard BL, Roden EE, and Johnson CM (2013) An anoxic, Fe(II)-rich, U-poor ocean 3.46 billion years ago. Geochimica et Cosmochimica Acta, 120: 65–79. PDF
Shen-Miller J, Aung LH, Turek J, Schopf JW, Tholandi M, Yang M, and Czaja AD (2013) Centuries-old viable fruits of Nelumbo nucifera Gaertn var. China Antique. Tropical Plant Biology, 6(2-3): 53–68. PDF
Czaja AD, Johnson CM, Beard BL, Roden EE, Li W, and Moorbath S (2013) Biological Fe oxidation controlled deposition of banded iron formation in the ca. 3,770 Ma Isua Supracrustal Belt (West Greenland). Earth and Planetary Science Letters, 363: 192–203. PDF Suppl File Suppl Tables
Czaja AD, Johnson CM, Roden EE, Beard BL, Voegelin AR, Nägler TF, Beukes NJ, and Wille M (2012) Evidence for free oxygen in the Neoarchean ocean based on coupled iron–molybdenum isotope fractionation. Geochimica et Cosmochimica Acta, 86: 118–137. PDF Suppl File Suppl Tables
Czaja AD, Johnson CM, Yamaguchi KE, and Beard BL (2012) Comment on “Abiotic Pyrite Formation Produces a Large Fe Isotope Fractionation” by Guilbaud et al. Science, 335: 538. PDF
Beard BL, Handler RM, Scherer MM, Wu L, Czaja AD, Heimann A, and Johnson CM (2010) Iron isotope fractionation between aqueous ferrous iron and goethite. Earth and Planetary Science Letters, 295: 241–250. PDF
Czaja AD, Johnson CM, Beard BL, Eigenbrode JL, Freeman KH, and Yamaguchi KE (2010) Iron and carbon isotope evidence for ecosystem and environmental diversity in the ~2.7 to 2.5 Ga Hamersley Province, Western Australia. Earth and Planetary Science Letters, 292: 170–180. PDF Suppl File Suppl Table S1 Suppl Table S2
Czaja AD, Kudryavtsev AB, Cody GD, and Schopf JW (2009) Characterization of permineralized kerogen from an Eocene fossil fern. Organic Geochemistry, 40(3): 353–364. PDF
Schopf JW, Kudryavtsev AB, Czaja AD, and Tripathi AB (2007) Evidence of Archean life: stromatolites and microfossils. Precambrian Research, 158(3–4): 141–155. PDF
Czaja AD, Kudryavtsev AB, and Schopf JW (2006) New method for the microscopic, nondestructive acquisition of ultraviolet resonance Raman spectra from plant cell walls. Applied Spectroscopy, 60(4): 352–355. PDF
Schopf JW, Kudryavtsev AB, Agresti DG, Czaja AD, and Wdowiak TJ (2005) Raman imagery: a new approach to assess the geochemical maturity and biogenicity of permineralized Precambrian microscopic fossils. Astrobiology, 5: 333–371. PDF
Jones CS, Cardon ZG, and Czaja AD (2003) A phylogenetic view of low level CAM in Pelargonium (Geraniaceae). American Journal of Botany, 90: 135–142. PDF
Cardon ZG, Czaja AD, Funk JL, and Vitt P (2002) Periodic carbon flushing to roots of Quercus rubra seedlings affects soil respiration and rhizosphere microbial biomass. Oecologia, 133: 215–223. PDF
Schopf JW, Kudryavtsev AB, Agresti DG, Wdowiak TJ, and Czaja AD (2002) Images of Earth’s earliest fossils? – Reply. Nature, 420: 477. PDF
Schopf JW, Kudryavtsev AB, Agresti DG, Wdowiak TJ, and Czaja AD (2002) Laser-Raman imagery of Earth's earliest fossils. Nature, 416: 73–76. PDF
Bosak T, Shuster DL, Scheller E, Siljeström S, Zawaski M, Mandon L, Simon JI, Weiss BP, Stack KM, Mansbach EN, Treiman A, Benison K, Brown A, Czaja AD, Farley K, Hausrath EM, Herd CDK, Johnson J, Mayhew LE, Minitti ME, Williford K, Wogsland BV, Zorzano MP, Hurowitz J, Hand K, Allwood A, Amundsen HEF, Bell J, Benzerara K, Beyssac O, Cable M, Calef F, Caravaca G, Calef FJ III, Catling D, Clavé E, Cloutis E, Cohen BA, Cousin A, Flannery D, Forni O, Fouchet T, Gibbons E, Gómez F, Gupta S, Hickman-Lewis K, Kalucha H, Lopes-Reyes G, Maki J, Maurice S, Randazzo N, Rice J, Sephton M, Sharma S, Steele A, Tate C, Uckert K, Udry A, and Wiens R. (2024) Astrobiological potential of rocks acquired by the Perseverance rover at a sedimentary fan front in Jezero crater, Mars. AGU Advances, 5, e2024AV001241. https://doi.org/10.1029/2024AV001241
Phua YY, Ehlmann BL, Siljeström S, Czaja AD, Beck P, Connell S, Wiens RC, Jakubek RS, Williams RME, Zorzano M-P, Minitti ME, Pascuzzo AC, Hand KP, Bhartia R, Kah LC, Mandon L, Razzell Hollis J, Scheller EL, Sharma S, Steele A, Uckert K, Williford KH, and Yanchilina AG (2024) Characterizing hydration carrier phases in altered rocks of Jezero Crater fan and floor geologic units with SHERLOC on Mars 2020 Journal of Geophysical Research: Planets, 129, e2023JE008251. https://doi.org/10.1029/2023JE008251
Zorzano M-P, Martínez G, Polkko J, Tamppari LK, Newman C, Savijärvi H, Goreva Y, Viúdez‑Moreiras D, Bertrand T, Smith M, Hausrath EM, Siljeström S, Benison K, Bosak T, Czaja AD, Debaille V, Herd CDK, Mayhew L, Sephton MA, Shuster D, Simon JI, Weiss B, Randazzo N, Mandon L, Brown A, Hecht MH, and Martínez‑Frías J. (2024) Present-day thermal and water activity environment of the Mars Sample Return collection. Scientific Reports 14, 7175. https://doi.org/10.1038/s41598-024-57458-4
Benison, K. C., Gill, K. K., Sharma, S., Siljeström, S., Zawaski, M., Bosak, T., Broz A, Clark BC, Cloutis E, Czaja AD, Flannery D, Fornaro T, Gómez F, Hand K, Herd CDK, Johnson JR, Madariaga JM, Madsen MB, Martinez-Frías J, Nachon M, Núñez JI, Pedersen DAK, Randazzo N, Shuster DL, Simon J, Steele A, Tate C, Treiman A, Uckert K, Williams AJ, and Yanchilina A. (2024) Depositional and diagenetic sulfates of Hogwallow Flats and Yori Pass, Jezero crater: Evaluating preservation potential of environmental indicators and possible biosignatures from past Martian surface waters and groundwaters. Journal of Geophysical Research: Planets, 129 (2), e2023JE008155. https://doi.org/10.1029/2023JE008155
Jakubek RS, Bhartia R, Uckert K, Asher SA, Czaja AD, Fries MD, Hand K, Haney NC, Razzell Hollis J, Minitti M, Sharma SK, Sharma S, and Siljeström S. (2023) Calibration of Raman Bandwidths on the SHERLOC Deep UV Raman and Fluorescence Instrument aboard the Perseverance Rover. Applied Spectroscopy. https://doi.org/10.1177/00037028231210885
#Siljeström S, #Czaja AD, *Corpolongo A, Berger EL, Li AY, Cardarelli E, Abbey W, Asher SA, Beegle LW, Benison KC, Bhartia R, Bleefeld BL, Burton AS, Bykov SV, Clark B, DeFlores L, Ehlmann BL, Fornaro T, Fox A, Gómez F, Hand K, Haney NC, Hickman-Lewis K, Hug WF, Imbeah S, Jakubek RS, Kah LC, Kivrak L, Lee C, Martínez-Frías J, McCubbin FM, Minitti M, Moore K, Morris RV, Núñez JI, Osterhout JT, Phua YY, Randazzo N, Razzell Hollis J, Rodriguez C, Roppel R, Scheller EL, Sephton ME, Sharma SK, Sharma S, Steadman K, Steele A, Tice M, Uckert K, VanBommel S, Williams AJ, Williford KH, Winchell K, Wu M, Yanchilina A, and Zorzano M-P. (2024) Evidence of Sulfate-Rich Fluid Alteration in Jezero Crater Floor, Mars. Journal of Geophysical Research: Planets 129 (1), e2023JE007989. https://doi.org/10.1029/2023JE007989 (#Contributed equally as co-lead authors)
*Corpolongo A, Jakubek RS, Abbey W, Asher SA, Baker D, Beegle LW, Berger EL, Bhartia R, Brown AJ, Burton AS, Bykov SV, Cardarelli E, Cloutis EA, Conrad P, Czaja AD, DeFlores L, Flannery D, Fornaro T, Fries M, Haney NC, Hickman-Lewis K, Kah L, Lee C, McCubbin FM, Minitti M, Morris RV, Hollis JR, Roppel R, Scheller EL, Sharma S, Shkoylar S, Siljeström S, Steadman K, Steele A, Uckert K, Wogsland BV, and Yanchilina A. (2023) SHERLOC Raman mineral detections of the Mars 2020 Crater Floor Campaign, Journal of Geophysical Research: Planets 128 (3), e2022JE007455. https://doi.org/10.1029/2022JE007455
Sharma S, Roppel RD, Murphy AE, Beegle LW, Bhartia R, Steele A, Razzell Hollis J, Siljeström S, McCubbin FM, Asher SA, Abbey WJ, Allwood AC, Berger EL, Bleefeld BL, Burton AS, Bykov SV, Cardarelli EL, Conrad PG, Corpolongo A, Czaja AD, DeFlores LP, Edgett K, Farley KA, Fornaro T, Fox AC, Fries MD, Harker D, Hickman-Lewis K, Huggett J, Imbeah S, Jakubek RS, Kah LC, Lee C, Liu Y, Magee A, Minitti M, Moore KR, Pascuzzo A, Sanchez-Vahamonde CR, Scheller EL, Shkolyar S, Stack KM, Steadman K, Tuite M, Uckert K, Werynski A, Wiens RC, Williams AJ, Winchell K, Kennedy MR, and Yanchilina A (2023) Diverse organic-mineral associations in Jezero crater, Mars. Nature, 619: 724–732. https://doi.org/10.1038/s41586-023-06143-z
Simon JI, Hickman-Lewis K, Cohen BA, Mayhew LE, Shuster DL, Debaille V, Hausrath EM, Weiss BP, Bosak T, Zorzano M-P, Amundsen HEF, Beegle LW, Bell JF III, Benison KC, Berger EL, Beyssac O, Brown AJ, Calef F, Casademont TM, Clark B, Clavé E, Crumpler L, Czaja AD, Fairén AG, Farley KA, Flannery DT, Fornaro T, Forni O, Gómez F, Goreva Y, Gorin A, Hand KP, Hamran S-E, Henneke J, Herd CDK, Horgan BNH, Johnson JR, Joseph J, Kronyak RE, Madariaga JM, Maki JN, Mandon L, McCubbin FM, McLennan SM, Moeller RC, Newman CE, Núñez JI, Pascuzzo AC, Pedersen DA, Poggiali G, Pinet P, Quantin-Nataf C, Rice M, Rice JW Jr., Royer C, Schmidt M, Sephton M, Sharma S, Siljeström S, Stack KM, Steele A, Sun VM, Udry A, VanBommel S, Wadhwa M, Wiens RC, Williams AJ, and Williford KH. (2023) Samples Collected from the Floor of Jezero Crater with the Mars 2020 Perseverance Rover, Journal of Geophysical Research: Planets 128, e2022JE007474. https://doi.org/10.1029/2022JE007474
Sun VZ, Hand KP, Stack KM, Farley KA, Simon JI, Newman C, Sharma S, Liu Y, Wiens RC, Williams AJ, Tosca N, Alwmark S, Beyssac O, Brown A, Calef F, Cardarelli EL, Clavé E, Cohen B, Corpolongo A, Czaja AD, Del Sesto T, Fairen A, Fornaro T, Fouchet T, Garczynski B, Gupta S, Herd CDK, Hickman-Lewis K, Horgan B, Johnson J, Kinch K, Kizovski T, Kronyak R, Lange R, Mandon L, Milkovich S, Moeller RC, Núñez J, Paar G, Pyrzak G, Quantin-Nataf C, Shuster DL, Siljeström S, Steele A, Tice M, Toupet O, Udry A, Vaughan A, and Wogsland B. (2023) Overview and Results from the Mars 2020 Perseverance Rover’s First Science Campaign on the Jezero Crater Floor. Journal of Geophysical Research: Planets 128, e2022JE007613. https://doi.org/10.1029/2022JE007613
Tingle KE, Porter SM, Raven MR, Czaja AD, Webb SM, and Bloeser B (2023) Organic preservation of vase-shaped microfossils from the late Tonian Chuar Group, Grand Canyon, Arizona, USA. Geobiology, 00, 1–20. https://doi.org/10.1111/gbi.12544
Lima-Zaloumis J, Neubeck A, Ivarsson M, Bose M, Greenberger R, Templeton AS, Czaja AD, Kelemen P, and Edvinsson T (2022) Microbial biosignature preservation in carbonated serpentine from the Samail Ophiolite, Oman. Nature Communications Earth and Environment, 3(231). https://doi.org/10.1038/s43247-022-00551-1
*Osterhout JT, Schopf JW, Kudryavtsev AB, Czaja AD, and Williford KH (2022) Deep-UV Raman spectroscopy of carbonaceous Precambrian microfossils: Insights into the search for past life on Mars. Astrobiology, 22(10): 1239-1254. https://doi.org/10.1089/ast.2021.0135
Farley KA, Stack KM, Shuster DL, Horgan BHN, Hurowitz JA, and 110 coauthors (2022) Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars. Science, 377(6614): https://doi.org/10.1126/science.abo2196
Johnson CM, Zheng XY, Djokic T, Van Kranendonk MJ, Czaja AD, Roden EE, and Beard BL (2022) Early Archean biogeochemical iron cycling and nutrient availability: New insights from a 3.5 Ga land-sea transition, Earth-Science Reviews, 228: 103992. https://doi.org/10.1016/j.earscirev.2022.103992.
Hackley PC, Kus J, Mendonça Filho JG, Czaja AD, Borrego AG, Životić D, Valentine BJ, and Hatcherian JJ (2022) Characterization of bituminite in Kimmeridge Clay by confocal laser scanning and atomic force microscopy. International Journal of Coal Geology, 251: 103927. https://doi.org/10.1016/j.coal.2022.103927. link to paper
Riedman LA, Porter SM, and Czaja AD (2021) Phosphatic scales in vase shaped microfossil assemblages from Death Valley, Grand Canyon, Tasmania and Svalbard. Geobiology. https://doi.org/10.1111/gbi.12439 PDF
*Gangidine A, Walter MR, Havig JR, Jones C, Sturmer DM, and Czaja AD. (2021) Trace elements in ancient microfossils as a biosignature for Earth and Mars. Life, 11(2): 142. https://doi.org/10.3390/life11020142 PDF
Gan T, Luo T, Pang K, Zhou C, Zhou G, Wan B, Li G, Yi Q, Czaja AD, and Xiao S. (2021) Cryptic terrestrial fungus-like fossils of the early Ediacaran Period. Nature Communications, 12: Article number 641. https://doi.org/10.1038/s41467-021-20975-1 PDF
Hegna TA, Czaja AD, and Rogers DC (2020) Raman spectroscopic analysis of the composition of the clam-shrimp carapace (Branchiopoda: Laevicaudata, Spinicaudata, Cyclestherida): a dual calcium phosphate–calcium carbonate composition. Journal of Crustacean Biology 1–5. https://doi.org/10.1093/jcbiol/ruaa078 PDF
Peng X, Guo Z, Du M, Czaja AD, Papineau D, Chen S, Xu H, Li J, Ta K, Bai S, and Dasgupta S (2020) Past endolithic life in metamorphic ocean crust. Geochemical Perspective Letters 14, 14–19 https://doi.org/10.7185/geochemlet.2017 PDF
Smith AJB, Beukes NJ, Gutzmer J, Johnson CM, Czaja AD, Nhleko N, de Beer F, Hoffman JW, and Awramik SM (2020) Life on a Mesoarchean marine shelf: insights from the world’s oldest known granular iron formation. Scientific Reports, 10, 10519. https://doi.org/10.1038/s41598-020-66805-0 PDF
*Gangidine A, Havig JR, Hannon JS, and Czaja AD (2020) Silica precipitation in a wet-dry cycling hot spring simulation chamber. Life, 10(3), https://doi.org/10.3390/life10010003 PDF
*Gangidine A, Havig JR, Fike DA, Jones C, Hamilton TL, and Czaja AD (2020) Trace element concentrations in hydrothermal silica deposits as a potential biosignature. Astrobiology, 20(3): 1–12. PDF
*Osterhout JT, Czaja AD, Fralick PW, and Bartley JK (2019) Preservation of carbon isotopes in kerogen from thermally altered Mesoproterozoic lacustrine microbialites. Canadian Journal of Earth Science, 56: 1017–1026, dx.doi.org/10.1139/cjes-2018-0309. PDF
Manning-Berg AR, Wood RS, Williford KH, Czaja AD, and Kah LC (2019) The taphonomy of Proterozoic microbial mats and implications for early diagenetic silicification, Geosciences, 9, 40, doi:10.3390/geosciences9010040. link to paper
Beaty DW, et al. (70 co-authors) (2019), The potential science and engineering value of samples delivered to Earth by Mars sample return, Meteoritics & Planetary Science, 54(S1): S3–S152, doi: 10.1111/maps.13242. PDF
Czaja AD, Johnson CM, Beard BL, and Van Kranendonk MJ (2018) A multistage origin for Neoarchean layered hematite-magnetite BIF from the Weld Range, Yilgarn Craton, Western Australia. Chemical Geology, 488: 125–137. link to paper
Muscente, AD, Czaja, AD, Tuggle, J, Winkler, C, and Xiao, S (2018) Manganese oxides resembling microbial fabrics and their implications for recognizing inorganically preserved microfossils. Astrobiology.
Vrazo MB, Diefendorf AF, Crowley BE, and Czaja AD (2018) Late Cretaceous marine arthropods relied on terrestrial organic matter as a food source: geochemical evidence from the Coon Creek lagerstätte in the Mississippian embayment. Geobiology. PDF
Guo Z, Czaja AD, Chen S, Ta K, and Peng X (2018) Cellular taphonomy of well-preserved Gaoyuzhuang microfossils: a window into the preservation of ancient cyanobacteria. Precambrian Research, 304: 88–89. PDF
Muscente AD, Czaja AD, Riedman LA, and Colleary C (2017) Organic Matter in Fossils. In Encyclopedia of Geochemistry, White WM, Ed. Springer International Publishing. PDF
Kang J, Czaja AD, and Guliants VV (2017) Carbon dioxide as feedstock in selective oxidation of propane. European Journal of Inorganic Chemistry. 2017(40): 4757–4762 PDF
Smith AJB, Beukes NJ, Gutzmer J, Czaja AD, Johnson CM, and Nhleko N (2017) Oncoidal granular iron formation in the Mesoarchaean Pongola Supergroup, southern Africa: Textural and geochemical evidence for biological activity during iron deposition. Geobiology, 15: 731–749. PDF
Czaja AD, Beukes NJ, and Osterhout JT (2016) Sulfur-oxidizing bacteria prior to the Great Oxidation Event from the 2.52 Ga Gamohaan Formation of South Africa. Geology, 44(12): 983–986. PDF Suppl File Suppl video A Suppl Video B Suppl Video C
d'Abzac F-X, Czaja AD, Beard, BL, Schauer JJ, and Johnson CM (2014) Iron distribution in size-resolved aerosols generated by UV-femtosecond laser ablation: Influence of cell geometry and implications for in situ isotopic determination by LA-MC-ICP-MS. Geostandards and Geoanalytical Research, 38(3): 293–309. PDF
Wilmeth DT, Dornbos SQ, Isbell JL, and Czaja AD (2014) Putative domal microbial structures in fluvial siliciclastic facies of the Mesoproterozoic (1.09 Ga) Copper Harbor Conglomerate, Upper Peninsula of Michigan, USA. Geobiology, 12: 99–108. PDF
d'Abzac F-X, Beard BL, Czaja AD, Konishi H, Schauer J, and Johnson CM (2013) Iron isotope composition of particles produced by UV-femtosecond laser ablation of natural oxides, sulfides, and carbonates. Analytical Chemistry, 85: 11885–11892. PDF
Li W, Czaja AD, Van Kranendonk MJ, Beard BL, Roden EE, and Johnson CM (2013) An anoxic, Fe(II)-rich, U-poor ocean 3.46 billion years ago. Geochimica et Cosmochimica Acta, 120: 65–79. PDF
Shen-Miller J, Aung LH, Turek J, Schopf JW, Tholandi M, Yang M, and Czaja AD (2013) Centuries-old viable fruits of Nelumbo nucifera Gaertn var. China Antique. Tropical Plant Biology, 6(2-3): 53–68. PDF
Czaja AD, Johnson CM, Beard BL, Roden EE, Li W, and Moorbath S (2013) Biological Fe oxidation controlled deposition of banded iron formation in the ca. 3,770 Ma Isua Supracrustal Belt (West Greenland). Earth and Planetary Science Letters, 363: 192–203. PDF Suppl File Suppl Tables
Czaja AD, Johnson CM, Roden EE, Beard BL, Voegelin AR, Nägler TF, Beukes NJ, and Wille M (2012) Evidence for free oxygen in the Neoarchean ocean based on coupled iron–molybdenum isotope fractionation. Geochimica et Cosmochimica Acta, 86: 118–137. PDF Suppl File Suppl Tables
Czaja AD, Johnson CM, Yamaguchi KE, and Beard BL (2012) Comment on “Abiotic Pyrite Formation Produces a Large Fe Isotope Fractionation” by Guilbaud et al. Science, 335: 538. PDF
Beard BL, Handler RM, Scherer MM, Wu L, Czaja AD, Heimann A, and Johnson CM (2010) Iron isotope fractionation between aqueous ferrous iron and goethite. Earth and Planetary Science Letters, 295: 241–250. PDF
Czaja AD, Johnson CM, Beard BL, Eigenbrode JL, Freeman KH, and Yamaguchi KE (2010) Iron and carbon isotope evidence for ecosystem and environmental diversity in the ~2.7 to 2.5 Ga Hamersley Province, Western Australia. Earth and Planetary Science Letters, 292: 170–180. PDF Suppl File Suppl Table S1 Suppl Table S2
Czaja AD, Kudryavtsev AB, Cody GD, and Schopf JW (2009) Characterization of permineralized kerogen from an Eocene fossil fern. Organic Geochemistry, 40(3): 353–364. PDF
Schopf JW, Kudryavtsev AB, Czaja AD, and Tripathi AB (2007) Evidence of Archean life: stromatolites and microfossils. Precambrian Research, 158(3–4): 141–155. PDF
Czaja AD, Kudryavtsev AB, and Schopf JW (2006) New method for the microscopic, nondestructive acquisition of ultraviolet resonance Raman spectra from plant cell walls. Applied Spectroscopy, 60(4): 352–355. PDF
Schopf JW, Kudryavtsev AB, Agresti DG, Czaja AD, and Wdowiak TJ (2005) Raman imagery: a new approach to assess the geochemical maturity and biogenicity of permineralized Precambrian microscopic fossils. Astrobiology, 5: 333–371. PDF
Jones CS, Cardon ZG, and Czaja AD (2003) A phylogenetic view of low level CAM in Pelargonium (Geraniaceae). American Journal of Botany, 90: 135–142. PDF
Cardon ZG, Czaja AD, Funk JL, and Vitt P (2002) Periodic carbon flushing to roots of Quercus rubra seedlings affects soil respiration and rhizosphere microbial biomass. Oecologia, 133: 215–223. PDF
Schopf JW, Kudryavtsev AB, Agresti DG, Wdowiak TJ, and Czaja AD (2002) Images of Earth’s earliest fossils? – Reply. Nature, 420: 477. PDF
Schopf JW, Kudryavtsev AB, Agresti DG, Wdowiak TJ, and Czaja AD (2002) Laser-Raman imagery of Earth's earliest fossils. Nature, 416: 73–76. PDF
