Karen Junge

Karen Junge’s research focuses on microbial life at the interface of the biosphere and geosphere, with an emphasis on life in ice. In the field and laboratory she examines how polar, cold-adapted (psychrophilic) bacteria survive and function at extremely low temperatures, and how they interact with and shape their physical and chemical environment.

Her work explores the genomic, proteomic, physiological, and ecological adaptations that enable life in frozen systems, and how microbial communities respond to changing environmental conditions. By combining approaches from molecular biology, microbiology, geophysics, and atmospheric science, she develops methods to study microorganisms in ice under conditions that closely reflect their natural environment.

Polar ice systems also serve as natural analogs for icy environments beyond Earth. In this context, her research contributes to broader questions in Astrobiology, including how life persists under extreme conditions and how we might detect it in ice-covered worlds.

• Frantz, C. M., Crump, B. C., Carpenter, S., Firth, E., Orellana, M. V., Light, B., & Junge, K. (2026). Microbial Ecology of Rotten Sea Ice: Implications for Arctic Carbon Cycling with Global Warming. Microorganisms, 14(2), 482. https://doi.org/10.3390/microorganisms14020482

• Gentilhomme, A. S., Dhakar, K., Timmins-Schiffman, E., Chaw, M., Firth, E., Junge, K., & Nunn, B. L. (2025). Proteomic Insights into Psychrophile Growth in Perchlorate-Amended Subzero Conditions: Implications for Martian Life Detection. Astrobiology. https://doi.org/10.1089/ast.2024.0065

• Ewert, M., Nunn, B. L., Firth, E., & Junge, K. (2025). Metabolic Responses, Cell Recoverability, and Protein Signatures of Three Extremophiles: Sustained Life During Long-Term Subzero Incubations. Microorganisms, 13(2), 251. https://doi.org/10.3390/microorganisms13020251

• Ni Z, Arevalo R Jr, Bardyn A, Willhite L, Ray S, Southard A, Danell R, Graham J, Li X, Chou L, Briois C, Thirkell L, Makarov A, Brinckerhoff W, Eigenbrode J, Junge K, Nunn BL. (2023). Detection of Short Peptides as Putative Biosignatures of Psychrophiles via Laser Desorption Mass Spectrometry. Astrobiology, 23(6), 657-669. PubMed PMID: 37134219. https://doi.org/10.1089/ast.2022.0138. 
   

• Mudge, M.C., Nunn, B.L., Firth, E., Ewert, M., Hales, K., Fondrie, W.E., Noble, W.S., Toner, J., Light, B., and Junge, K.A. (2021), Subzero, saline incubations of Colwellia psychrerythraea reveal strategies and biomarkers for sustained life in extreme icy environments. Environ Microbiol, 23: 3840-3866, doi:10.1111/1462-2920.15485.

• Frantz, C.M., Light, B., Farley, S.M., Carpenter, S., Lieblappen, R., Courville, Z., Orellana, M.V., and Junge, K.: Physical and optical characteristics of heavily melted “rotten” Arctic sea ice, The Cryosphere, 13, 775-793, doi:10.5194/tc-13-775-2019, 2019.
   

• Junge, K., Cameron, K. and Nunn, B., 2019. Diversity of Psychrophilic Bacteria in Sea and Glacier Ice Environments—Insights Through Genomics, Metagenomics, and Proteomics Approaches. In Microbial Diversity in the Genomic Era (pp. 197-216). Academic Press. https://doi.org/10.1016/B978-0-12-814849-5.00012-5

• Nunn, B.L., K. Slattery, K. A. Cameron, E. Timmins-Schiffman, and K. Junge. 2015. Proteomics of Colwellia psychrerythraea at subzero temperatures – a life with limited movement, flexible membranes and vital DNA repair. Environmental Microbiology. 111, 9009-9014.

• Cameron, K.A., B. Hagedorn, M. Dieser, B.C. Christner, K. Choquette, R. Sletten, B. Crump, C. Kellogg, and K. Junge. 2015. Diversity and potential sources of microbiota associated with snow on western portions of the Greenland Ice Sheet. Environmental Microbiology, 17:594-609.

• Dieser, M., E.L.J.E. Broemsen, K.A. Cameron, G.M. King, A. Achberger, K. Choquette, B. Hagedorn, R. Sletten, K. Junge, and B.C. Christner. 2014. Molecular and biogeochemical evidence for methane cycling beneath the western margin of the Greenland Ice Sheet. ISME Journal, 8:2305-2316.

• Junge, K., B.C. Christner, and J.T. Staley, “Diversity of Psychrophilic Bacteria from Sea Ice – and Glacial Ice Communities“. In K. Horikoshi, G. Antranikian, A. Bull, F. Robb, and K. Stetter (eds), Extremophiles Handbook. Springer, Heidelberg, Germany. 1247 pp, 2011.

• Skidmore, M., Jungblut, Anne, and Urschel, M. and K. Junge., “Cryospheric Environments in Polar regions (Glaciers and Ice Sheets, Sea Ice, Ice Shelves).”, In Polar Microbiology. L.Whyte and R. Miller (eds). ASM Press., (2011), Accepted.

• Junge, K., and B.D. Swanson,’ High-resolution ice nucleation spectra of sea-ice bacteria: Implications for cloud formation and life in frozen environments‘, Biogeosciences Discussion, 4, 4261-4282, 2008.

• Mock, T. and K. Junge, “Psychrophilic Diatoms: Mechanisms for Survival in Freeze-thaw cycles”, Algae and Cyanobacteria in Extreme Environments, Springer Netherlands; DOI10.1007/978-1-4020-6112-7, pp. 343 to 364, 2007.

• M.L. Laucks, A. Sengupta, K. Junge, E.J. Davis and B.D. Swanson. “Comparison of psychro-active Arctic marine bacteria and common mesophilic bacteria using surface-enhanced raman spectroscopy”. Appl. Spectroscopy 10: 1222-1228, 2006.

• K. Junge, H. Eicken, B. D. Swanson and, J. W. Deming. “Bacterial incorporation of leucine into protein down to –20°C with evidence for potential activity in subeutectic saline ice formations”. Cryobiol. 52: 417–429, 2006.

• Deming, J. W. and K. Junge. ‘‘Colwellia’’, in The Proteobacteria, Part B, Bergey’s Manual of Systematic Bacteriology, G. T. Staley, D. J. Benner, N. R. Krieg, and G. M. Garrity, Eds. (Springer, New York, 2005), 2nd., Vol. 2, pp. 447–454, 2005.

• Junge, K., H. Eicken, and J. W. Deming. A Microscopic Approach to Investigate Bacteria under In-Situ Conditions in Arctic Lake Ice: Initial Comparisons to Sea Ice. In Bioastronomy 2002: Life Amongst the Stars IAU Symposium 213, eds. R. Norris and F. Stootman. Astronomical Society of the Pacific, San Francisco: 381-388, 2004.

• Junge, K., H. Eicken, and J. W. Deming. “Bacterial activity at -20°C in Arctic wintertime sea ice“. Appl. Environ. 70: 550-557, 2004.

• Junge, K., H. Eicken, and J. W. Deming. “Motility of Colwellia psychrerythrea str. 34H observed at subzero temperatures“. Appl. Environ. Microbiol. 69: 4282–4284, 2003.

• Junge, K., J.F. Imhoff, J.T. Staley and J.W. Deming, “Phylogenetic diversity of numerically important Arctic sea-ice bacteria cultured at subzero temperature”, Microb. Ecol. 43: 315-328, 2002.

• Krembs, C., H. Eicken, K. Junge, and J. W. Deming, “High concentrations of exopolymeric substances in wintertime sea ice: Implications for the polar ocean carbon cycle and cryoprotection of diatoms“, Deep-Sea Res. I 9: 2163 –2181, 2002.

• Skoog, A. K. Whitehead, F. Sperling, and K. Junge, “Microbial glucose uptake and growth along a horizontal nutrient gradient in the North Pacific“, Limnol. Oceanogr., 47(6):1676–1683, 2002.

• Staley, J. T, K. Junge, and J. Deming. And some like it cold: sea ice microbiology. In Biodiversity of Life, eds. J. T Staley and A.-L. Reysenbach, pp. 423-438, 2001.

• Junge, K., C. Krembs, J. Deming, A. Stierle and H. Eicken, “A microscopic approach to investigate bacteria under in situ conditions in sea-ice samples“, Ann. Glaciol. 33: 304-310, 2001.

• Junge K, J. J. Gosink, H.-G. Hoppe and J. T. Staley. Arthrobacter, Brachybacterium and Planococcus isolates identified from Antarctic sea ice brine. Description of Planococcus mcmeekenii, sp. nov. Syst Appl Microbiol 21: 306-314, 1998.