Serpentinizing Systems Science Working Group (SSSWG)

Introduction

Serpentinization is a process occurs through space and time in our solar system when ultramafic rocks come into contact with water. There is compelling evidence for active and ancient serpentinization processes on Earth, across regions of the surface and subsurface of Mars, beneath the surface of icy satellites such as Enceladus and Europa, and beyond. However, many of the potential couplings between serpentinization and life activity remain enigmatic; thus well-defined planetary targets and potential biosignatures urgently need to be identified and validated.

Serpentinization occurs across a large range of environmental temperatures and water/rock interaction regimes and may be one of the most common habitable environments within our solar system. Diagnostic mineral assemblages, hyperalkaline fluids, and dissolved gases such as H2, CH4 and other reduced carbon compounds (e.g. low molecular weight hydrocarbons and organic acids) – all critical components for biological energy transduction – are then produced to variable extents during serpentinization. The extreme disequilibria between rocks and fluids in serpentinizing systems result in strong pH and chemical gradients that may have been exploited to support the earliest metabolisms and modes of energy conservation.

Recent interrogations of modern serpentinizing systems on Earth are beginning to yield the first information regarding the abundance, diversity and functional properties of life forms that can be sustained under extremes of pH and oxidant and carbon limitation. Innovative assessments of the biochemistry and evolutionary biology of active life within serpentinizing systems, coupled with detailed geochemical data, thermodynamic calculations, kinetic constraints, and mechanistic models, will help to establish new conceptual frameworks for the habitability of rocky ecosystems. Moreover, there will be numerous opportunities to identify diagnostic biological and chemical signatures of living serpentinizing systems, to optimize life-detection strategies, and to assess the potential for the preservation of such biosignatures through time.

Thus during 2016, a Serpentinizing Systems Science Working Group will be assembled. The initial objectives include: 1) supporting interdisciplinary efforts focused on the identification, interpretation and astrobiological significance of serpentinizing systems, and 2) creating pathways for sharing and building upon recent discoveries in Serpentinizing Systems Science across the NAI and within Astrobiology community. The activities and communication within the Serpentinizing Systems Science Working Group will be organized around four themes: Planetary Systems, Terrestrial Field Systems, Experimental Systems and Modeling.

CAN Teams: Univ. of Colorado, USC, SETI Inst., JPL, U.C.-Riverside, Univ. of Montana, Univ. of Wisconsin, Univ. of Illinois

Activities
Next Steps

A “Workshop Without Walls” was held in early 2017. This virtual event was organized by Tori Hoehler, Jen Blank and Alexis Templeton, and the content was developed by three Theme leads, Billy Brazelton, Tom McCollom and Steve Vance. These three Themes explored over three days included “Serpentinization on Earth” (Day 1), “Experiment and Theory” (Day 2), and “Planetary Systems” (Day 3).

Links to the 3 days of talks and discussion can be found here:

https://nai.nasa.gov/seminars/featured-seminar-channels/workshops-without-walls/2017/1/31/serpentinizing-systems-science/

First organizational meeting at AbSciCon 2015

The first organizational meeting of the Serpentinizing Systems Science Working group (SSSWG) was held at the June 2015 AbSciCon meeting. Over 25 researchers attended the kick-off session to discuss topics and formation of this science working group.

2015 Director's Discretionary Fund Projects

Low Pressure Serpentinization Reactions on Mars
Lead Investigator: Adrian Brown (SETI Institute Team)
Co-Investigators: Alexis Templeton, Lisa Mayhew (University of Colorado Boulder, Rock-Powered Life Team), Michael Russell (JPL Icy Worlds Team)

This proposal will simulate the formation of talc-carbonate assemblages on Mars, similar to deposits detected at Nili Fossae. The presence of talc in association with carbonate is particularly suggestive of serpentinization with a medium to high degree of CO2 in the reacting fluid. The study will focus on tantalizing clues that talc and carbonate may form together in the shallow (10s of meters) Martian crust. This type of system would have high astrobiological potential and be relatively accessible to in situ investigation. This project creates a bridge between the Serpentinizing Systems Working Group and the Biosignature Detection Working Group. The collaboration between three NAI teams has mission relevance and forges a new collaboration between synergy working groups. The proposal supports a post-doc who will work with Dr. Templeton.


Probing the Isotope Systematics of Low-Temperature Serpentinites
Lead Investigator: Alexis Templeton (Rock-Powered Life Team, University of Colorado Boulder)
Co-Investigators: Eric Ellison and Lisa Mayhew (Rock-Powered Life Team), Clark Johnson and John Valley (Wisconsin Astrobiology Research Consortium Team)

This proposal will: 1) develop standards for microanalysis of δ18O in serpentine and brucite minerals formed in serpentinizing reactions under different temperature/fluid regimes, and 2) carry out initial isotopic exchange experiments to gain mechanistic insight into the formation of iron‐bearing brucite and serpentine through isotopic tracers of Mg, Fe, Si, and O. This is a foundational proposal in its introduction of isotopic techniques to the study of the biogeology of serpentinizing systems. The outcome will provide a framework for cross-team investigations in the Serpentinizing Systems Synergy group with implications for other NAI teams and projects. The proposal funds an early career scientist.


Catalytic Diversity at the Emergence of Metabolism: Hydrothermal Carbon Dioxide Reduction on Fe/Ni-Sulfide Catalysts
Lead Investigator: Laura Barge (JPL Icy Worlds Team)
Co-Investigators: Pablo Sobron (SETI Institute Team), Michael Russell (JPL Icy Worlds Team), Yuichiro Ueno (Earth-Life Science Institute), Shawn McGlynn (Tokyo Metropolitan University)

This proposal aims to simulate and quantify the emergence of catalyst diversity for carbon fixation in prebiotic alkaline hydrothermal vents. The objectives are to 1) test the reduction of CO2 on hydrothermal minerals at 70°C; 2) test addition of nickel—a significant component for CO2 reduction and metabolism; and 3) test the effectiveness of adding organics to investigate their ability to affect catalyst diversity and functionality. This proposal strongly supports the serpentinization synergy theme by integrating the research of JPL Icy Worlds and SETI Institute Fingerprints of Life NAI teams; the new NAI Biosignature Detection and Serpentinization Working Groups; NAI’s international partner organization the Japan Astrobiology Consortium through the Earth-Life Science Institute (ELSI) in Tokyo, Japan; and the new ELSI Origins Network. The proposal also supports two early career Co-Investigators.