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Executive Summary

The Rock-Powered Life NASA Astrobiology Institute team addresses systems on Earth and on rocky moons and planets such as Mars, Europa and Enceladus, where there is the potential to support life activity through water/rock reactions. In particular, the RPL NAI focuses on the mechanisms whereby energy may be released from the low-temperature hydration of mafic and ultramafic rocks, and the distribution, activity and biochemistry of the life forms that can harness this energy. RPL also seeks to detect the chemical and biological signatures of rock-hosted microbial activity. Our target rock types for the most intensive focus include serpentinites – rocks rich in olivine and pyroxene that have been partially hydrated during water/rock reactions – that may provide habitable environments at key moments in time and space in our solar system and beyond.

The 12 investigators of the Rock-Powered Life (RPL) team are collectively pursuing two overarching themes of research. Theme 1: Systems undergoing low-temperature serpentinization as test-beds for determining habitability, and Theme 2: Experimental constraints on pathways of water/rock interaction, in the presence and absence of biological processes. Each of these themes feeds into our collective efforts to address the following central objectives:

• Defining the pathways that control how energy is released from ultramafic rocks as they react with low-temperature fluids
• Identifying and interpreting the process rates and ecology in systems undergoing water/rock reaction
• Quantifying the geochemical and mineralogical progression of water/rock reactions in the presence and absence of biology
• Characterizing microbial communities within rock-hosted ecosystems and evaluating their metabolic activities
• Developing and testing predictive models of biological habitability during water/rock interaction

In Year 1, RPL team members have initiated our Theme 1 activities through first field campaigns at our three core study sites in serpentinizing systems: the Coast Range Ophiolite Microbial Observatory (CROMO) in California, the Samail ophiolite in Oman, and through Expedition 357 to the Atlantis Massif. CROMO is currently being utilized for long-term monitoring of dissolved aqueous geochemistry and gases, rock magnetic properties, ground water levels and changes in microbial diversity in low H2 ecosystems. Deep wells drilled into peridotite in Oman were accessed by RPL team members in January 2015 to obtain the first deep subsurface water samples and biomass of serpentinite-fluid organisms, and to use these materials to design approaches for culturing, DNA and RNA extraction, gene sequencing and mineralogical characterization. By the end of Year 1, a dozen RPL team members had formally applied to participate in the Oman Drilling Project (http://omandrilling.ac.uk) for 2016-2018. Similary, 4 RPL successfully applied to be members IODP Expedition 357 to Atlantis Massif along the Mid-Atlantic Ridge (http://www.eso.ecord.org/expeditions/357/357.php), as part of a critical two-month drilling operation to recover the first serpentinite cores from the subsurface adjacent to the Lost City Hydrothermal field. In addition, several RPL co-Is are effectively utilizing long-term research sites at Yellowstone National Park and Canadian subglacial ecosystems to further develop and test hypotheses regarding the habitability of water/rock supported ecosystems, particularly through unexpected pathways of energy transfer and the cycling of Fe, S and methane.

To date, the new field campaigns in low-temperature serpentinizing systems have been successful in recovering biomass from the fluids migrating through peridotite rocks, and RPL investigators have been able to detect the presence of critical energy sources such as H2, methane, ammonium and organic acids, as well as surprisingly high concentrations of oxidants such as sulfate and nitrate. Moreover, we have strong evidence for dynamic changes in rock mineralogy and magnetic properties associated with habitable conditions, and we have our first insights into the phylogeny of the most abundant organisms present in subsurface fluids across geochemical gradients. These are critical pieces of information for developing our studies that assess the mechanisms of low-temperature serpentinization, and for seeking the metabolic processes that are sustained in such systems. RPL team members have also developed several spectroscopic methods to characterize the geochemistry of serpentinites, through sample swaps of CROMO and Oman rocks between RPL labs. Our method development for detailed spectroscopic microscale geochemical and biological mapping also now sets the stage for further correlative analyses and biosignature detection efforts with JPL, WARC, SETI and the LU NAI teams as well.

RPL has spent substantive time establishing the framework for Theme 2 as well, where we are conducting experimental and modeling studies of low-temperature serpentinization pathways and associated life activity. First, several RPL labs are actively culturing anaerobic organisms and consortia from subsurface serpentinite fluids, in order to pursue genome sequencing of novel serpentinite-hosted organisms, and to design experiments where the rates and products of biologically-influenced water/rock reactions can be quantitatively constrained through a combination of transcriptomic, isotopic and spectroscopic analyses. Our greatest successes in Year 1 include the cultivation of methanogens and iron reducing and sulfate reducing organisms from Oman and CROMO fluids. Once these cultivars are well characterized, they will become critical components of future cross-team experimental studies, as well as model systems that we can base our design of in-situ activity assays in the deep subsurface, and which we can use in our search for organic biomarkers in serpentinizing systems. In addition, RPL investigators are carefully designing optimized protocols for DNA and RNA extraction and preservation from low-biomass samples, which will be critical for our work with cores and fluids to be recovered from Atlantis Massif and Oman, as well as from experiments that support the growth of only small numbers of cells.

New reaction vessels have been designed for low-temperature water/rock reaction experiments, enabling the establishment of mineral hydration studies that will reveal the key metastable phases involved in low-temperature hydrogen production. In parallel, a RPL reaction-path modeling group has been established to utilize the most appropriate thermodynamic and kinetic data available to simulate the alteration of rocks that undergo progressive stages of low-temperature serpentinization. RPL has chosen to utilize the EQ3/6 package to build numerical models that will significantly extend beyond the cell-scale reaction transport models RPL investigators have previously established to define habitable conditions capable of supporting methanogenesis.

In Year 1, the Rock-Powered Life team has focused substantial time and effort on the recruitment and establishment of personnel (graduate student, postdoctoral, and technical staff) to effectively meet our research objectives. We have also built effective communications and collaboration between our numerous distributed research groups. RPL holds monthly scientific video-conferences attended by >30 participants per occasion, and Communications Director Lisa Mayhew develops and distributes a monthly newsletter, as well as a valuable web presence at http://www.colorado.edu/lab/rockpoweredlife/ , where it is possible to find extensive information about our current activities and team of co-investigators, as well as details about the sixteen students and postdocs that have been recruited to RPL so far. In addition, Templeton, Boyd and Mayhew convened two in-person meetings for the RPL team since announcement of the award – first at AGU in Dec. 2014, and then formally with the majority of co-Is and students in a meeting held at the time of AbSciCon 2015. RPL investigators also presented twenty abstracts at AbSciCon in Chicago, and all co-Is have presented RPL related work in Year 1 at several international venues, Gordon Conferences and academic institutions.

Lastly, the RPL team is increasingly engaged in active collaborations with several of the other NAI teams, particularly through the newly designed “Serpentinizing Systems Science” working group and “Biosignatures” working group. Some of the new collaborations between RPL and Wisconsin, SETI and the Jet Propulsion laboratory will be supported by 2015 Director’s Discretionary funds, some are ideas embedded into new proposals submitted to the NASA PSTAR and Exobiology program or the NASA Postdoctoral Program, and some will soon be integrated into the Projects you will read about in our Year 2 report at the end of 2016! All of the interactions involve exchange of personnel and in-person visits between our 9 member institutions and the participating nodes of the NASA Astrobiology Institute.