ProfessorSamuel Kounaves

The Kounaves group's research interests are aimed at unraveling fundamental questions in planetary science using modern in-situ analytical systems designed to study the geochemistry and biogeochemistry of extraterrestrial environments, and using biomarkers and Molecular Assembly Theory to identify past/present microbial life.

As Co-I and Lead Scientist (PI) 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 ClO₄^- may 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 difficulty of instruments to detect organics on Mars (Viking/GCMS; Phoenix/TEGA; & Curiosity/SAM). It could also act as an electron donor/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 organic biomarkers 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 archea 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 grants to (1) investigate how potential biomarker molecules on the surface of Mars would be altered or destroyed in the search for life and (2) , develop a chemical sensor array to unambiguously detect microbial life and determine 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.Planetary Chemical Analysis and Astrobiology. More about the Kounaves Research Group can be found HERE.