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Early Habitable Environments and the Evolution of Complexity Principal Investigator - David J. Des Marais


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By Jane Braxton Little

Dave Des Marais in Lassen National Park with studentsMayson Trujillo stretches across a rock at the edge of a stream cascading through Lassen Volcanic National Park. Braving snow from an advancing blizzard, she meticulously collects a sample of the sulphur-scented water. Trujillo, a senior at Red Bluff High School in California, is intent on the task at hand: gathering data that may hold clues for early life on Earth—and potentially, Mars.

To reach the stream, Trujillo and 13 classmates snowshoed a mile into the center of an ancient volcano—for them, a routine field trip in a one-of-a-kind collaboration with NASA Astrobiology Institute's Ames Team. The park’s mud pots and fumaroles can exceed 240˚F, too hot for most creatures but potentially habitable to the types of microbes that populated Earth 3.5 billion years ago. Understanding those conditions could help astrobiologists interpret signs of life on other planets, particularly Mars, where the Curiosity rover is scooping up soil. And the database of hydrothermal features the students have been building, based on sample analyses they do back at their high school lab, could guide future exploration of the Red Planet.

Dave Des Marais, a NASA geochemist who has been involved in Mars missions since the 1990s, started the Red Bluff program six years ago. He says the work being done by the students—possibly NASA's only high school astrobiology interns—is sophisticated research, worthy of college juniors and seniors. By providing "real science in all its gory details," Des Marais says, he hopes to develop a cadre of professional astrobiologists who will continue the search long after he and his colleagues are gone.

The class is no easy A. In fact, interns don’t even receive credit for their after-school commitment. But who else gets to have snowball fights with NASA scientists, asks Trujillo, as she seals her water sample into a sterile tube. "And it'd be so crazy if we actually find something out there on Mars," she says, "even if it's only a microbe."

This article originally appeared in the September 2014 issue of Popular Science.


On August 1-3, 2014, NASA Ames Team scientists, park rangers, and astronomers celebrated all that is out of this world during the Dark Sky Festival at Lassen Volcanic National Park.

Ames Team members presented the following talks and programs:

Lassen Dark Sky Festival 2014 Program Guide—NASA Astrobiology Tent. Provided an opportunity to meet with NASA scientists to find out more about astrobiology―the study of the origin, evolution, distribution, and future of life in the universe!

—Astrobiology: Searching for Aliens? What can rocks tells us about ancient life on other planets and what exactly is astrobiology? Presented by NASA Ames and Blue Marble Space Institute of Science astrobiologist Sanjoy Som.

—Exploring Mars for Evidence of Life. Evidence of interactions between volcanism and water has been discovered on Mars. NASA Ames senior research scientist, Dave Des Marais, explained how Lassen is studied to search for clues of ancient life on Mars.

—How Hot Springs Support Life. NASA Ames scientist Kirsten Fristad delved into the formation and chemistry of hydrothermal systems that can support life in unbelievably extreme conditions.

—Microbes and Life on Other Planets. NASA Ames and SETI Institute scientist Niki Parenteau talked about how microscopic organisms in Lassen’s hydrothermal areas help direct the search for life on other planets.

—Two Years on Mars. Dave Blake, NASA Ames senior research scientist, shared results from the first two years of the exploration by the Mars Science Laboratory focusing on mineralogy of the Red Planet.

- Intern Recognition Night and Public Lecture, May 6, 2014

Dave Des Marais and Student Interns at Warner ValleyThe Ames Team Astrobiology Student Intern Program, a partnership between Red Bluff High School, Lassen Volcanic National Park and NASA Ames Research Center, held its annual intern recognition night and public lecture on May 6, 2014, at Red Bluff High School. The student interns gave a presentation on the results of their year-long research project studying Warner Valley at Lassen. The students also addressed the big picture implications of their project – by examining the hydrothermal environments at Lassen, and how their research will help NASA direct the search for evidence of microbial life in ancient hydrothermal systems on Mars.

Dave Des Marais gave the keynote lecture titled, "Mars Exploration, Lassen and Life." Des Marais is the NASA Ames Team principal investigator and a member of the science teams of NASA's 2003 Spirit and Opportunity Rover mission, the 2004 Mars Reconnaissance Orbiter mission, and the 2012 Curiosity Rover mission.

The student presentation and keynote lecture can be viewed here.


The NAI Ames Team has partnered with the California Academy of Sciences in the “Dark Universe Program,” a new cosmology show that began on January 31, 2014. On Saturdays from February 8th through March 15th, the Ames team will discuss the Mars Science Laboratory Mission and will demonstrate and engage museum visitors in real-time hands-on analyses of Martian analog rocks using an Earthly version of CheMin – the X-ray diffraction instrument onboard the Curiosity rover.

Niki Parenteau and Tom Bristow at California Academy of SciencesOn February 8, 2014, Ames team members Niki Parenteau and Tom Bristow discussed the Mars Science Laboratory mission with the general public at the California Academy of Sciences. With the Curiosity rover’s CheMin instrument in the background, Bristow demonstrates the use of a rock sieve to a young and eager audience.

In addition, team members will participate in the “Connect with a Scientist!” program and engage visitors in interactive conversations about their career paths, research projects and scientific discoveries.

For additional information on the “Dark Universe Program” and “Connect with a Scientist!” visit California Academy of Sciences.

"Serpentinization, Chemistry, and Life at the Coast Range Ophiolite Microbial Observatory," by Tori Hoehler

On November 5, 2013, Tori Hoehler gave a free public talk titled, "Serpentinization, Chemistry, and Life at the Coast Range Ophiolite Microbial Observatory" as part of the SETI Institute Colloquium Series.

SETI Talk - Tori Hoehler - November 2013Serpentinizing systems -- in which aqueous alteration of ultramafic rocks yields highly reducing and alkaline fluids -- have been suggested as possible niches for photosynthesis-independent ecosystems on Earth and beyond. To date, most research has focused on systems characterized by extremes of pH or redox potential, and on surface expressions (e.g., springs or vents) where deeply-sourced fluids mix with the surface chemistry.

To capture a broader cross-section of the geochemical diversity in serpentinizing systems, and to assess the biological potential of unmixed subsurface fluids, we established the Coast Range Ophiolite Microbial Observatory, a series of wells drilled into the actively serpentinzing subsurface of the McLaughlin Natural Reserve (Lake County, California).

Observations of mineralogy and microbial community composition in cored materials, aqueous geochemistry in recovered well fluids, and biological process rates in fluids and cored materials were combined with geochemical and bioenergetic models that relate host-rock composition and hydrology to biological potential. Both modeled and observational results indicate that natural variability in serpentinizing systems can generate a broad spectrum of geochemical conditions, and correspondingly wide range of biological potential. This range of conditions appears to cross the boundary from habitable to uninhabitable with regard to biological energy requirements, tolerance to extremely alkaline pH, or both.

"Microbial Mats and Earth's Early Biosphere," by Dave Des Marais

On September 17, 2013, Dave Des Marais gave a free public talk titled, "Microbial Mats and Earth's Early Biosphere" as part of the SETI Institute Colloquium Series.

Dave Des Marais - SETI Talk - Microbial Mats

Photosynthetic microbial mats are complete microbial ecosystems that can construct laminated "miniature reefs" called stromatolites. Their fossilized equivalents are among the oldest most abundant evidence of early life. Des Marais and his colleagues have studied cyanobacterial mats in an arid coastal environment at the Exportadora de Sal, S.A. (ESSA) salt works, Guerrero Negro, Baja California Sur, Mexico. He shows how the mats' oxygenated zone reflects a dynamic balance between vigorous photosynthetic O2 production and O2 consumption by diverse sulfide-oxidizing and heterotrophic bacteria.

Anoxygenic phototrophs and sulfate-reducing bacteria are quantitatively important consumers of dissolved organic matter. He shows how several previously unknown rRNS gene sequences of bacteria and eukarya were identified, indicating that these mats can extend our understanding of the diversity and early evolution of benthic microbial communities. He continues to catalog the diversity of lipid biosignatures, whose fossil equivalents can record the diversity of ancient microbial ecosystems.


Trailside Sign at Lassen National ParkThe second NASA astrobiology-themed trailside sign was installed at Lassen Volcanic National Park in August, 2013. The Ames Team, in partnership with Lassen and Lockheed Martin, is creating a series of four NASA astrobiology-themed trailside signs to further engage national park visitors in exploration and scientific discovery. The sign, “Lassen, Ancient Earth, Mars?,” highlights the link between Lassen’s hydrothermal areas and research on Mars. The Ames Team is studying hydrothermal habitats at Lassen to understand the origins and evolution of life in a planetary context. The first trailside sign was installed at Sulphur Works in May 2012. Trailside signs have been shown to be an effective tool for doing interpretation and outreach, impacting the public’s attitude toward science. The astrobiology interpretive trailside signs are a visible demonstration of Lockheed Martin and the Ames Team’s commitment to informal science education.


Dave BlakeCongratulations to Dave Blake who was awarded the Outstanding Leadership Medal at the 2013 Presidential Rank and NASA Honor Awards Ceremony at Ames Research Center on August 29, 2013, for development of a flight-qualified Chemistry and Mineralogy X-ray diffraction instrument for the Mars Science Laboratory mission.

The prestigious Outstanding Leadership Medal is awarded to government employees for notable leadership accomplishments that have significantly influenced the NASA Mission.  Sustained leadership and exceptionally high-impact leadership achievements should demonstrate the individual's effectiveness in advancing the Agency's goals and image in present and future terms.


Lassen Dark Sky Festival 2013Lassen Volcanic National Park and NASA hosted the Dark Sky Festival on August 9-11, 2013. This year's Dark Sky Festival included scale solar system hikes, special junior ranger astronomy activities, workshops, demonstrations from astronomy educators, and a chance to learn about the exciting field of astrobiology from NASA scientists and Red Bluff High School interns. Visitors learned about Lassen's role in the search for life from NASA Ames Team scientists in keynote programs featuring: Dave Blake, the principal investigator of the CheMin instrument onboard the Mars Curiosity rover; Kevin Zahnle, a planetologist with the Ames Team; and Dave Des Marais, the Principal Investigator of the Ames Research Center Team.

- With Dr. David Des Marais

Every first Tuesday of the month, S.A.G.A.N. ( hosts a program called "Talk to an Astrobiologist", where the public is invited to interact with a high-profile astrobiologist, who replies to questions on video. Each session lasts about an hour.

Talk to an Astrobiologist - with Dr. David Des MaraisAmes Team member and Principal Investigator, David Des Marais received a Ph.D. in Geochemistry from Indiana University in 1974. His long-term research interests have been the biogeochemical carbon cycle and the early evolution of Earth and its biosphere. His areas of specialization have included the stable isotope geochemistry of carbon in lunar samples, meteorites and oceanic basalts, the biogeochemistry of microbial communities in hypersaline environments, and the biogeochemistry of ancient (Precambrian) carbonates and organic matter. He serves on the editorial boards of the two journals Astrobiology and Geobiology. Des Marais is an interdisciplinary scientist for astrobiology on both the Mars Exploration Rover 2003 science operations working group and the Mars 2005 CRISM infrared spectrometer.

- An Evening Dialogue with the NASA Kepler Mission Leaders -

The Search for Other Earths The Search for Other Earths Tori Hoehler was a featured speaker at Lawrence Hall of Science Auditorium on Thursday, July 18, 2013. This program was for science educators, science students, and the general public.

With almost 3000 planet candidates discovered by Kepler since its launch in 2009, at no other time in history has the possibility of finding an Earth-like planet been so within our reach. Attendees learned about the groundbreaking hunt for exoplanets and its implications for the search for life elsewhere.


Casini Titan AtmosphereCollaborating with a group of Spanish Astronomers, Ames Team members Christiaan Boersma and Lou Allamandola found strong evidence for the presence of polycyclic aromatic hydrocarbon (PAH) molecules in the atmosphere of Saturn's largest moon, Titan. Utilizing the wealth of PAH spectra available in the NASA Ames PAH IR Spectroscopic Database, they analyzed data obtained by NASA's spacecraft Cassini.

Long time a mystery, the haze making up Titan's atmosphere can finally be attributed to PAHs. Focussing on the 3 micron region, dominated by a strong methane feature, the team found unexplained substructure. After careful subtraction of the methane emission, a residual component peaking at 3.28 micron remained - indicative for the presence of aromatic material.

Image of dark side of Titan moon taken from Cassini spacecraft provided by NASA JPL-Caltech Space Science Institute.Turning to the NASA Ames PAH IR Spectroscopic Database and after taking appropriate solar illumination into account, a blind computational analyzes was able to reproduce the observed emission feature and provide additional insight into the molecular properties of the emitting PAH mixture.

Titan is considered an early Earth analog and as such the presence of PAHs might provide important insight into the chemistry of the formation of life on our own planet.

The Spanish led group published their results in a paper that recently appeared in The Astrophysical Journal. Simultaneously, the European Space Agency and NASA issued a press release highlighting the results.

MARS IN 3D - Images from the Viking Mission

Mars in 3D NASA's twin Viking 1 and 2 spacecraft orbited, landed and collected breathtaking imagery of the Martian landscape between 1976 and 1979. Following the completion of the mission, 3D imagery from the orbiters and landers was transformed into a stereoscopic dual-16mm film by the late Dr. Elliott Levinthal of Stanford University, a member of the Viking imaging team.

The Mars in 3D Project was the committed effort to restore the film and its soundtrack to modern high-definition digital video and audio. Now, more than thirty years after its debut—the soundtrack to footage of the red planet from the Viking missions—a historic piece of computer music, has been restored by its Stanford creators.

On Friday, June 14, 2013, the Century Cinema 16 theater in Mountain View, was filled with an audience of about 450 to watch a special midnight showing of a meticulously restored version of "Mars in 3D," and for just the second time in a public viewing, the soundtrack will be heard at the quality the composers intended.

Tori Hoehler was invited to speak at this special event. His talk was titled, "Postcards from a Neighbor World."

Visit the Stanford Magazine article Return to Mars for additional information or to order a copy of the DVD, Mars in 3D.


Amanda Cook visited Sedgwick Elementary School, in Cupertino, California, where she spoke with 96 third graders who were studying stars, constellations, and Galileo. Using sequentially zoomed images of the Orion Nebula, Cook revealed to the students how a very small object in the sky can actually be something quite large. When showed just how big the Solar System is, in comparison to the Orion Nebula, the third graders were in awe. In addition, Cook talked about stellar winds blowing dust and gas into clumps that would soon form new stars.

Orion Nebula and how stars are born

The students asked many great questions after being introduced to the Mars Science Laboratory and O/OREOS spacecraft, and to the Galilean satellites: What is a supernova? How big is the constellation Pegasus? Why did NASA name a satellite after a cookie?


Ken StedmanA novel virus genome discovered in an extreme environment suggests recombination between unrelated groups of RNA and DNA viruses, by Geoffrey S. Diemer and Ames Team member Kenneth M. Stedman, published in Biology Direct 2012, 7:13, has been awarded the 7th Annual BioMed Central Research Award. This prestigious award was given as part of a BioMed Central organized event at Experimental Biology. Ken commented on winning the award and said, "We're extremely honored at this award considering all of the wonderful research that is being published at BioMed Central."

BioMed Central's Annual Research Awards celebrate excellence in scientific research made freely available through open access publishing within a portfolio of over 250 scientific and medical journals. Nominations are open to the scientific community and the winning articles, selected by dedicated judging panels, are chosen for their innovation and high-quality execution and discussion. The awards also acknowledge outstanding individual or institutional efforts made to support open access to research, as well as researchers demonstrating leadership in data sharing.


Oklahomans in SpaceThe Oklahoma Historical Society interviewed Ames Team member Andy Mattioda for an upcoming documentary regarding Oklahomans and the Space Program. The program will highlight the contributions of NASA engineers, scientists, lawyers, astronauts and even NASA administrators, all with Oklahoma backgrounds. The documentary is being developed in conjunction with the Oklahoma Educational Television Authority as part of the Oklahomans and Space Educational Program and will air later this year. Additional educational material for the program can be found on the Oklahoma Historical Society website. The producer of the documentary, Bill Moore, has also published a book regarding Oklahoman's contributions to the space program. Andy Mattioda will be featured in the second edition of the book.


Tori Hoehler in Greenhouse CBS News Video - Is Anybody Out There? The question "Is anybody out there?" grows more tantalizing with the discovery of each new far-off planet. Starry nights inspire wonder, and wondering: Is there life out there? (CBS News)

On April 28, 2013, CBS News Sunday Morning aired a segment titled "NASA's Kepler seeks to answer: Is anybody out there?" CBS News Correspondent Barry Petersen has been talking to scientists searching for clues.

As part of this segment, Petersen interviewed Ames Team member Tori Hoehler about his research on the simple types of life he imagines we might expect to find on planets light years away. In his greenhouse at NASA Ames Research Center, Tori showed Petersen his "window back in time" and explained that we had a microbial planet for probably more than two billion years, and if you wanted to put a picture in your head of what that might look like, this is it. As for what kind of life that may be out there, he says look to Earth and its extremes. Hoehler says organisms have been found in the hot springs of Yellowstone, which reach a pH close to battery acid. "Remarkable capabilities of these sorts of organisms," he said.

To see this CBS News Sunday segment in its entirety, click the picture or the link above. To see Tori Hoehler's interview in the video, scroll to the 3:23 point of this 5 minute video.


Tori Hoehler - Student Letter 1 Tori Hoehler - Student Letter 1 Tori Hoehler was the featured speaker for his son's second grade class at Benjamin Bubb Elementary School in Mountain View, California. The focus of his talk was "rocks." He explained to the students that the study of geology is like any other language — that every rock tells a story and they need to learn how to read it.

Following his talk, Tori received a stack of "thank you" letters from the students; two are featured here (click on the letters and drawing to view full-size). These letters certainly bring to light the value of NASA scientists interacting with kids!

As a geochemist and microbial ecologist, Tori Hoehler is the Lead Co-Investigator of the Ames Team's study of Mineralogical Traces of Early Habitable Environments.

Tori Hoehler - Student Letter 2 Tori Hoehler - Student Letter 2 Tori Hoehler - Student Letter 2 Drawing


Sanjoy Som at California Aerospace Week at State CapitolThe 2nd Annual California Aerospace event was held on March 12-13, 2013, at the State Capitol in Sacramento. This event is intended to educate state lawmakers about California's economically important aerospace industry.

Ames Team members Tori Hoehler and Sanjoy Som attended this event to represent CheMin.  They set up and manned a CheMin booth, demonstrated X-ray diffraction analysis in real time, and discussed how mineralogy equates to habitability, with legislators and the general public alike.

Sanjoy explained to visitors the importance of investigating rocks on other planets because rocks hold clues to the environment they were formed in. He talked about a rock rich in the California state mineral "serpentine" and described what information lies within. Likewise, Mars scientists use different instruments on board the Mars Rover to reveal their secrets, thus turning the pages of Mars history through the information hidden in the rocks.


Team members were invited to present their research at the NASA Astrobiology Institute (NAI) Executive Council meeting held on January 17-18, 2013, at Ames Research Center.

Ames Team Member Speak at NAI Executive Council Meeting

Principal Investigator, Dave Des Marais, talked about the overall theme of the Ames Team research, "Early Habitable Environments and the Evolution of Complexity," and explained the four approaches to understanding the origins of life.

Lou Allamandola continued with his presentation, "Tracking Cosmic Carbon's Evolution from the Solar System Across the Universe." He explained how researchers are taking Astrochemistry and Astrobiology out of the lab and into space by integrating laboratory work with different spacecraft missions and concepts associated with organics in space and extraterrestrial samples.

Tori Hoehler focused on understanding the interplay between "Rocks and Life" and how this interaction contributes to habitability. He talked about optimizing the use of CheMin as a tool for characterizing the habitability of Mars. Tori further expanded on the Coast Range Ophiolite Microbial Observatory (also know as The McLaughlin Drilling Project) and the Josephine Ophiolite Project which provides a natural lab for understanding mineral-based constraints on water, energy, temperature, pH (mineralogy -- habitability).

Andrew Pohorille explained that proteins are the main functional molecules of contemporary cells in his presentation, "How Proteins Became Functional." He continued the discussion talking about the search for understanding the puzzle of the origins of protein function.

Sandy Davis talked about "Solar System Evolution," and the research within his group. Jack Lissauer continued by giving an overview of NASA's Kepler Mission. He also discussed the simulations of delivery of water to terrestrial planets.

To learn more about the important work being done by the Ames Team, please visit the Research section of this website.

Click on the individual titles to view any of the above mentioned talks in full.


Dave Blake - CheMinThe Ames Team was invited to participate in Lassen Volcanic National Park's Second Annual Winter Film Festival on January 19-20, 2013.

At the request of the Lassen Park Superintendent, EPO provided two NASA films for public viewing: "Destination Innovation -- CheMin," starring Dave Blake, and the "Space Shuttle," narrated by William Shatner.


Niki ParenteauLinda JahnkeCongratulations to Niki Parenteau and Linda Jahnke for receiving a 2013 Science Innovation Fund (SIF) Award for their Astrobiology proposal "Coupling CheMin Mineralogical Analyses to the Preservation of Organics in Deposits Analogous to Ones Found on Mars." This project aims to leverage strengths at Ames Research Center, namely in situ mineralogical analyses using CheMin by Dave Blake, and traditional GC-MS analyses of lipids by Niki Parenteau and Linda Jahnke, in assessing the organic carbon preservation potential of phyllosilicates, sulfates, iron oxides, and amorphous silica at Lassen Volcanic National Park and Yellowstone National Park. Ames Team members Dave Des Marais and Tori Hoehler are also Co-Investigators.

The Science Mission Directorate (SMD) at NASA-HQ provided funding for this year's SIF. Of the 35 proposals submitted, 9 were selected. The SIF program is administered by the agency's Office of Chief Scientist, and was established to encourage early stage scientific research activities that are aligned with NASA's strategic goals and objectives.

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