Samuel Kounaves

Department of Chemistry
Pearson Chemistry Laboratory
62 Talbot Avenue
Tufts University 
Medford, MA 02155 

Office: P108-B || Phone: 617-627-3124


Research Homepage || Curriculum Vitae

Current Appointments


Professor of Chemistry, Department of Chemistry, Tufts University
Adjunct Professor, Department of Earth and Ocean Sciences, Tufts University
Visiting Professor, Department of Earth Science & Engineering, Imperial College London, UK

Research Affiliate, NASA-Jet Propulsion Laboratory, Pasadena, CA

Scientific Advisor, Centre of Astronomy & Astrophysics, Technical University Berlin, Germany




Postdoctoral Fellow, 1987-88, Harvard University, Cambridge, MA (James Young)
Postdoctoral Research Associate, 1985-86, S.U.N.Y. at Buffalo, NY (Janet Osteryoung)
Ph.D. (D.Sc.), 1985, Université de Genève, Geneva, Switzerland (Jacques Buffle)
B.A., 1975, M.S., 1978, California State University at San Diego/SDSU, CA (Alberto Zirino)


Research Interests

In-situ Planetary and Extreme Biogeochemical Analysis The Kounaves group research is aimed at unraveling fundamental questions in planetary science using modern in-situ analytical systems designed to study the biogeochemistry of extreme environments, where no one has gone before. As Co-I and Lead Scientist for the Wet Chemistry Lab (WCL) onboard NASA's Phoenix Mars Lander, Kounaves and his group performed the first wet chemical analysis of the martian soil using an array of electrochemical sensors. The experiments revealed an alkaline soil containing a variety of soluble minerals, but most surprising was the discovery of almost 1% perchlorate (ClO4-). Its discovery has wide ranging implications and has altered the way we view the chemistry of Mars and its potential to support life.


The presence of perchlorate as Ca(ClO4)2 suggests that Mars' surface may have been severely arid for at least the past ~600 million years. The ClO4- may also be responsible for brines due to its depression of the H2O freezing point to -78ºC, the control of planet-wide soil and atmospheric water content, and the dificulty of instruments to detect organics on Mars (VL/GCMS; Phx/TEGA; & MSL/SAM). It could also act as an electron doner/energy source for any indigenous subsurface microbes, and is both good & bad for human explorers (can provide energy, fuel, and oxygen, but is human health hazard). The group's recent discovery, that ClO4- may form on any Cl-bearing mineral surface that is exposed to UV and that the process generates intermediary oxychlorines and highly oxidizing radicals, has implications not only for the production of ClO4- and the alteration of organics on Mars, but also on Earth and perhaps throughout the solar system and beyond.


The discovery of ClO4- on Mars led the group to investigate the same possibility in Antarctica's McMurdo Dry Valleys. The study provided the first unambiguous discovery and clear evidence of the ubiquitous natural formation of perchlorate on Earth, with accumulation in arid environments and global atmospheric production. The discovery also suggests the hypothesis that the perchlorate reducing bacteria and arachea may be a remnant of a significant pre-oxygen Earth perchlorate ecosystem. The group has also recently confirmed ClO4-, ClO3-, and NO3-, in the Mars meteorites EETA79001 & Tissint, and also in lunar and chondrite meteorites.


In addition to the current investigations exploring Mars' geochemistry and its potential for supporting past or present microbial life in surface or subsurface environments, their research (funded by NASA and NSF) includes understanding the geochemical and environmental history as recorded by the chemistry of planetary surface materials, and the geobiochemistry in extreme environments on Earth in places such as the McMurdo and other Antarctica Dry Valleys, Death Valley, the Tindouf Basin (Morocco), and the Atacama Desert (Chile).


Most recently they have been funded by major NASA COLDTech and ICEE2 grants to develop a chemical sensor array to study the geochemistry, subglacial ocean chemistry, and habitability of Saturn's moon Enceladus by analysis of the ejected plume material and the surface ice on Europa. 



Recent & Selected Publications.


Methanogenic Archaea Can Produce Methane in Deliquescence-Driven Mars Analog Environments,
D. Maus, J. Heinz, J. Schirmack, A. Airo, S. P. Kounaves, D. Wagner, and D. Schulze-Makuch,
Nature Sci. Rep. 2020, 10:6, doi:10.1038/s41598-019-56267-4


Indigenous Organic-Oxidized Fluid Interactions in the Tissint Mars Meteorite, E. A. Jaramillo (Oberlin),
S. H. Royle, M. W. Claire, S. P. Kounaves, and M. A. Sephton, Geophys. Res. Lett. 2019, 46, 3090-3098, doi:10.1029/2018GL081335


The Production of Perchlorate (ClO4-) from Chlorite (ClO2-) and Chlorate (ClO3-) on Earth and Mars,
D. Liu and S. P. Kounaves, ACS Earth Space Chem. 2019, 3, 1678-1684, doi:10.1021/acsearthspacechem.9b00134.


Effects of Oxygen-Containing Salts on the Detection of Organic Biomarkers on Mars and in Terrestrial Analogue Soils, W. Montgomery, E. A. Oberlin, S. H. Royle, S. P. Kounaves, D. Schulze-Makuch, M. A. Sephton, Astrobiology, 2019, 19, 711-721, doi:10.1089/ast.2018.1888.


A Transitory Microbial Habitat in the Hyperarid Atacama Desert, D. Schulze-Makuch, D. Wagner,
S. P. Kounaves, et al., PNAS, 2018, 115, 2670-2675, doi:10.1073/pnas.1714341115


Survivability of 1-Chloronapthalene During Simulated Early Diagenesis: Implications for Chlorinated Hydrocarbon Detection on Mars, S. H Royle, J. Tan, S. P. Kounaves, M. A. Sephton, J. Geophys. Res.,
2018, 123, 2790-2802, doi:10.1029/2018JE005711


Perchlorate Driven Combustion of Organic Matter During Py-GC-MS: Implications for Organic Matter Detection on Earth & Mars, S. H Royle, E. A. Oberlin, J. S. Watson, W. Montgomery, S. P. Kounaves,
M. A. Sephton, J. Geophys. Res., 2018, 123, 1901-1909, doi:10.1029/2018JE005615


Effect of hydration state of Martian perchlorate salts on their decomposition temperatures during thermal extraction, S. H. Royle, W. Montgomery, S. P. Kounaves and M. A. Sephton, J. Geophys. Res., 2017, 122, 2793-2802, doi:10.1002/2017JE005381


The Origins of Perchlorate in the Martian Soil, B. L. Carrier and S. P. Kounaves, Geophys. Res. Lett.,
2015, 42, 3739-3745. doi:10.1002/2015GL064290


Evidence of Martian Perchlorate, Chlorate, and Nitrate in Mars Meteorite EETA79001: Implications for Oxidants and Organics, S. P. Kounaves, B. L. Carrier, G. D. O'Neil, S. T. Stroble, and M. W. Clair, Icarus, 2014, 229, 206-213. doi:10.1016/j.icarus.2013.11.012


Effects of Extreme Cold and Aridity on Soils and Habitability: McMurdo Dry Valleys as an Analog for the Mars Phoenix Landing Site, L. K. Tamppari, R. M. Anderson, P. D. Archer Jr., S. Douglas, S. P. Kounaves, C. P. McKay, D. W. Ming, Q. Moore, J. E. Quinn, P. H. Smith, S. Stroble, A. P. Zent, Antarctic Science, 2012, 24, 211-228. doi:10.1017/S0954102011000800


Soluble Sulfate in the Martian Soil at the Phoenix Landing Site, S. P. Kounaves, M. H. Hecht, J. Kapit, R. C. Quinn, D. C. Catling, B. C. Clark, D. W. Ming, K. Gospodinova, P. Hredzak, K. McElhoney, and J. Shusterman, Geophys. Res. Lett., 2010, 37, L09201. doi:10.1029/2010GL042613


Discovery of Natural Perchlorate in the Antarctic Dry Valleys and its Global Implications,
S. P. Kounaves, S. T. Stroble, R. M. Anderson, Q. Moore, D. C. Catling, S. Douglas, C. P. McKay, D. W. Ming, P. H. Smith, L. K. Tamppari, A. P. Zent, Environ. Sci. Technol., 2010, 44, 2360-64.


Wet Chemistry Experiments on the 2007 Phoenix Mars Scout Lander: Data Analysis and Results
S. P. Kounaves, M. H. Hecht, J. Kapit, K. Gospodinova, L. DeFlores, R. C. Quinn, W. V. Boynton, B. C. Clark, D. C. Catling, P. Hredzak, D. W. Ming, Q. Moore, J. Shusterman, S. Stroble, S. J. West, and S. M. Young,. J. Geophys. Res., 2010, 115, E00E10.


Detection of Perchlorate and the Soluble Chemistry of Martian Soil at the Phoenix Lander Site, M. H. Hecht,
S. P. Kounaves, R. C. Quinn, S. J. West, S. M. M. Young, D. W. Ming, D. C. Catling, B. C. Clark, W. V. Boynton, J. Hoffman, L. P. DeFlores, K. Gospodinova, J. Kapit, and P. H. Smith Science, 2009, 325, 64-67. doi:10.1126/science.1172466

Evidence for Calcium Carbonate at the Mars Phoenix Landing Site, W. V. Boynton, D. W. Ming,
S. P. Kounaves, et al., Science, 2009, 325, 61-64.


H2O at the Phoenix Landing Site, P. H. Smith, L. K. Tamppari, R. E. Arvidson, D. Bass, D. Blaney, W. V. Boynton, A. Carswell, D. C. Catling, B. C. Clark, T. Duck, E. DeJong, D. Fisher, W. Goetz, H. P. Gunnlaugsson, M. H. Hecht, V. Hipkin, J. Hoffman, S. F. Hviid, H. U. Keller, S. P. Kounaves, et al.,
Science, 2009, 325, 58-61
. doi:10.1126/science.1172339



Complete up-to-date list of publications can be found HERE.

Selected Media & E/PO Links

- ACS Kavli Award Lecture "The Chemistry of Finding Extraterrestrial Life" April 2019

- AAAS Annual Meeting News "Perchlorate on Mars" February 2013


- The Phoenix Mission: Onto the Ice PBS 1-hour special on the Phoenix Mars Mission


- NECN TV "Curiosity Rover Lands on Mars" August 2012


- WGBH 7 One Guest Interview May 2009


- NOVA ScienceNOW "Phoenix Lander Wet Chemistry with PBS/Tyson" July 2008


- MSNBC Today Show "Is There Life on Mars" Interview with Ann Curry June 2008



Organics discovered on Mars!
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