Samuel Kounaves

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

Office: P-108B

Office:617-627-3124 USCell:781-526-4137 UKCell:+44 7763 262356


Research Homepage: http://planetary.chem.tufts.edu/

Current Appointments


Professor of Chemistry, Department of Chemistry, Tufts University
Adjunct Professor, Department of Earth and Ocean Sciences, Tufts University
Research Affiliate, NASA-Jet Propulsion Laboratory, Pasadena, CA

Visiting Professor, Department of Earth Science & Engr, Imperial College London, UK




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 or on-site elctroanalytical systems designed to study the biogeochemistry of extreme environments, where no one has gone before. As Phoenix mission Co-I and Lead Scientist for the Wet Chemistry Lab (WCL), Professor Kounaves and his group performed the first wet chemical analysis of the martian soil. The experiments revealed an alkaline soil containing a variety of soluble minerals, but most surprising was the discovery of almost 1% perchlorate (ClO4-). Its presence at the Phoenix landing site (and confirmed by Curiosity at Gale Crater and in Mars meteorite EETA79001) has wide ranging implications that have altered the way we view the chemistry of Mars and its potential to support life. The formation of ClO4- generates intermediary oxychlorines and highly oxidizing radicals that appear to be responsible for the destruction of organics (and any life!) on the martian surface. The presence of the perchlorate as Ca(ClO4-) suggests that Mars' surface (at least around the Phoenix landing site) has been severely arid for at least the past ~600 million years. The ClO4- on Mars may also be responsible for brines & gullies due to depression of the H2O freezing point to -78C, control of planet-wide soil and atmospheric water content, has hindered the detection of organics (VL GCMS; Phx TEGA; & MSL SAM), could be a possible food 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 discovery of perchlorate on Mars led the group to investigate the same possibility in the Antarctic 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 that the perchlorate reducing bacteria and arachea may be a remnant of a significant pre-oxygen Earth perchlorate ecosystem.


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) also 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 Antarctic Dry Valleys, Death Valley, and mid-Atlantic deep-ocean thermal vents. They are also interested in applying similar techniques to investigate the surface and sub-glacial oceans on other planetary bodies such as Jupiter's moon, Europa.  The group's research in astrobiology is focused on exploring concepts and analytical techniques for unambiguous detection of microbial life in extraterrestrial settings, and the survivability of organics on Mars' surface.


Selected Recent Publications

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


Identification of the Perchlorate Parent Salts at the Phoenix Mars Landing Site and Possible Implications,
S. P. Kounaves, N. A. Chaniotakis, V. F. Chevrier, B. L. Carrier, K. E. Folds, V. M. Hansen, K. M. McElhoney, G. D. O'Neil, and A. W. Weber, Icarus, 2014, 232, 226-231. doi:10.1016/j.icarus.2014.01.016


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


Electrochemistry of Aqueous Colloidal Graphene Oxide on Pt Electrodes, G. D. O'Neil, A.W. Weber, R. Buiculescu, N. A. Chaniotakis, and S. P. Kounaves, Langmuir, 2014, 30, 9599-9606. doi:10.1021/la502053m


Comparison of the Phoenix Mars Lander Wet Chemistry Laboratory Soil Analyses with Antarctic Dry Valley Soils, Mars Meteorite EETA79001 Sawdust, and a Mars Simulant, S. T. Stroble, K. M. McElhoney, and
S. P. Kounaves, Icarus, 2013, 225, 933-939.


An Electrochemically Based Total Organic Carbon Analyzer for Planetary and Terrestrial On-Site Applications, S. T. Stroble and S. P. Kounaves, Anal. Chem., 2012, 84, 6271–6276. doi:10.1021/ac301704m


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


The Oxidation-Reduction Potential of Aqueous Soil Solutions at the Mars Phoenix Landing Site, R. C. Quinn, J. D. Chittenden, S. P. Kounaves, and M. H. Hecht, Geophys. Res. Lett., 2011, 38, L14202. doi:10.1029/2011GL047671


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 list of publications can be found HERE.

Selected Media & E/PO Links

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


- The Analytical Scientist "Quantitative Analysis and the Essence of Doing Good Science" January 2013


- 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



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