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Thermodynamics, Disequilibrium and Evolution (TDE)


Co-Chairs: Laura M. Barge (Jet Propulsion Laboratory, USA) and Eugenio Simoncini (INAF-Astrophysical Observatory of Arcetri, Florence, Italy)

The TDE Focus Group is intended to bridge the gap between researchers working on the theory and experimental aspects of the Origin of Life and astronomers and remote sensing researchers planning future space missions and deciding on future targets for the search for extraterrestrial life. It will concentrate on the entropy and energy requirements for life, how geochemical environments generate such far-from-equilibrium systems that could lead to prebiotic processes, and how this can inform our selection of potentially habitable planets and environments in the cosmos.

Earth displays abundant life that uses solar and chemical energy, the latter partly produced from geothermal energy. The convective mass transfer of heat driven by one or more of these forms of energy, from the very core of our planet through to the upper atmosphere, eventually conduces the interfacing of the chemical tensions appropriate to the nurturing of life. Disequilibrium on a cellular scale is made possible by the cell membrane, which maintains redox and pH gradients that are put to work by the cell. On a planetary scale, biological processes can establish and maintain far-from-equilibrium conditions. With this understanding of the fundamental character of life – that it depends upon disequilibrium in the environment as a source of energy, that it maintains a state of disequilibrium as a condition of life, and that it can mark its existence in an environment through the presence of disequilibrium – the TDE Focus Group seeks to integrate the astrobiology community around this paradigm to inform our search for life in the universe.

The transdisciplinary questions we address include: Under what energetic conditions does life start? What are the thermodynamic requirements of its processes? In which environments is it likely to exist? How might we find it?

To achieve these objectives, the TDE Focus Group will integrate its members and facilitate discussion by:

  • Creating an e-mail distribution list
  • Hosting a series of workshops to be held at astrobiology- and planetary-science-related institutes around the world. Workshops may be general or focused on TDE sub-topics of interest.
  • Organizing focused scientific sessions concerning the objectives of the focus group at larger conferences such as AbSciCon, AAS, and AGU.
  • Inspiring new research collaborations between TDE participants and developing these into viable products such as workshops, grant proposals, and published papers. Developing strong international connections between researchers at astrobiology / origin-of-life institutions and organizations to support long-term collaborative research efforts.


L. M. Barge, E. Branscomb, J. R. Brucato, S. S. S. Cardoso, J. H. E. Cartwright, S. O. Danielache, D. Galante, T. P. Kee, Y. Miguel, S. Mojzsis, K. J. Robinson, M. J. Russell, E. Simoncini, P. Sobron. (2017) Thermodynamics, Disequilibrium, Evolution: Far-From-Equilibrium Geological and Chemical Considerations for Origin-Of-Life Research. Orig Life Evol Biosph 47:39. DOI: 10.1007/s11084-016-9508-z


ELSI and the TDE held a joint workshop ELSI/TDE Meeting: “Requirements for Origin of Life Field Investigations” Oct. 5 – 7, 2016 at the Tokyo Institute of Technology. The goals of the workshop were: to define laboratory and analytical requirements for simulating seafloor settings on early Earth and other worlds, and to identify new technologies and operational strategies for the in-situ exploration of energetically active field sites that may represent analogs for environments in which life emerged.

The meeting agenda can be found here and the meeting webpage here


9th Meeting of the NASA Astrobiology Thermodynamics, Disequilibrium and Evolution (TDE) Focus Group: Exoplanetary Atmospheres and Habitability.
The 9th Meeting of the NAI TDE Focus Group was held at the Observatory of Côte d’Azur (OCA) in Nice (France) from October 12–18, 2015. This workshop was sponsored by the OCA, the Centre national de la recherche scientifique (CNRS), the Université Nice Sophia Antipolis, and the NASA Astrobiology Institute. TDE workshops are often focused on one particular topic of interest to members; this meeting was the first TDE workshop to be focused on Exoplanetary Atmospheres and Habitability, and was designed to inspire discussions about the connection between planetary habitability and its atmospheric disequilibrium, through the use of thermodynamic functions. There were a total of 31 invited talks in three sessions: Chemical disequilibrium in planetary atmospheres: from hot Jupiters to habitable planets; Icy moons, icy planets and the conditions for the emergence of life; and Modeling and observations of exoplanetary atmospheres: chemistry and physics. Along with invited talks we also had a tour of the observatory led by members of the OCA, where we visited the architectures of Charles Garnier and Gustave Eiffel, the Grand Equatorial telescope (18 m long, 76 cm lens’ diameter) and the “elbow” meridian telescope. Read more.

L. M. Barge, Y. Abedian, M. J. Russell, I. J. Doloboff, J. H. E. Cartwright, R. D. Kidd, I. Kanik. (2015) From Chemical Gardens to Fuel Cells: Generation of Electrical Potential and Current Across Self-Assembling Iron Mineral Membranes. Angewandte Chemie International Edition, 54, 28:8184-8187, DOI: 10.1002/anie.201501663.

L. M. Barge, S. S. S. Cardoso, J. H. E. Cartwright, G. J. T. Cooper, L. Cronin, A. De Wit, I. J. Doloboff, B. Escribano, R. E. Goldstein, F. Haudin, D. E. H. Jones, A. L. Mackay, J. Maselko, J. J. Pagano, J. Pantaleone, M. J. Russell, C. I. Sainz-Díaz, O. Steinbock, D. A. Stone, Y. Tanimoto, N. L. Thomas. (2015) From Chemical Gardens to Chemobrionics. Chemical Reviews, DOI: 10.1021/acs.chemrev.5b00014.

L. M. Barge, Y. Abedian, I. J. Doloboff, J. E. Nunez, M. J. Russell, R. D. Kidd, I. Kanik. (2015) Chemical Gardens as Flow-Through Reactors Simulating Natural Hydrothermal Systems. Journal of Visualized Experiments, in press.


8th Workshop of the NAI TDE Focus Group: Geochemical Requirements for the Emergence of Life. The meeting was held on November 10-14, 2014 in Tokyo at the Earth-Life Science Institute (ELSI). The aim of the workshop was to discuss the conditions for early Earth conducive for the emergence of life. Specifically, geochemical disequilibria generated at seafloor interfaces on wet rocky planets, and in particular, investigating the thermodynamic and chemical phenomena that emerge from this inherent disequilibria at water-rock interfaces. Visit the workshop website:
A workshop paper detailing the outcomes of the meeting was published by Springer Thermodynamics, Disequilibrium, Evolution: Far-From-Equilibrium Geological and Chemical Considerations for Origin-Of-Life Research

7th Workshop on Thermodynamics, Disequilibrium and Evolution. Focus: to explore the relationship between biological and planetary systems, considering their dynamic aspects. Dr. Douglas Galante along with the NAI TDE focus group hosted the 7th International Workshop on Thermodynamics, Disequilibrium and Evolution, on September 24 – 26, in Campinas, Brazil. The conference included a student poster session and a keynote lecture by Chemistry Nobel Laureate Ada Yonath. For more information, visit: /seminars/featured-seminar-channels/conferences-and-workshops/2014/9/24/workshop-on-thermodynamics-disequilibrium-and-evolution-tde/

Russell, M. J., Barge, L. M., Bhartia, R., Bocanegra, D., Bracher, P., Branscomb, E., Kidd, R., McGlynn, S., Meier, D., Nitschke, W., Shibuya, T., Vance, S., White, L. (2014) The Drive to Life on Rocky and Icy Worlds. Astrobiology,14, 4, 308-343.

L. M. Barge, T. P. Kee, I. J. Doloboff, J. M. P. Hampton, M. Ismail, M. Pourkashanian, J. Zeytounian, M. M. Baum, J. Moss, C.-K. Lin, R. D. Kidd, I. Kanik (2014) The Fuel Cell Model of Abiogenesis: A New Approach to Origin-of-Life Simulations. Astrobiology, 14(3):254-70.

Barge, L. M., Doloboff, I. J., Russell, M. J., VanderVelde, D., White, L. M., Stucky, G. D., Baum, M. M., Zeytounian, J., Kidd, R., Kanik, I. (2014) Pyrophosphate Synthesis in Iron Mineral Films and Membranes Simulating Prebiotic Submarine Hydrothermal Systems. Geochimica Cosmochimica Acta, 128, 1-12.

Cardoso SSS, Cartwright JHE. (2014) Dynamics of osmosis in a porous medium. R. Soc. open sci. 1: 140352.


6th TDE Focus Group Workshop: Out-of-Equilibrium Systems and Planetary Habitability, October 14th-16th, 2013; INAF-Astrophysical Observatory of Arcetri, Florence, Italy.

5th TDE Focus Group Workshop: Engines of Life: thermodynamic pathways to metabolism. The Beyond Center hosted the Physics of Living Matter workshop series in association with NAI TDE Focus Group to produce the Engines of Life: thermodynamic pathways to metabolism Workshop. The meeting had a foundational theme, focusing on the interplay of matter, energy and entropy in biological and prebiotic systems, with particular reference to the manner in which the chemical and physical conditions of the ancient environment, such as considerations of redox potentials and stoichiometry, may have constrained the possible pathways to metabolism.

Elbert Branscomb, Michael J. Russell. Turnstiles and bifurcators: The disequilibrium converting engines that put metabolism on the road. Biochimica et Biophysica Acta (BBA) – Bioenergetics. 2013 1827 (6): 806. doi:10.1016/j.bbabio.2012.10.003.

Julyan H. E. Cartwright, Bruno Escribano, Diego L. González, C. Ignacio Sainz-Díaz, and Idan Tuval (2013) Brinicles as a Case of Inverse Chemical Gardens. Langmuir 2013 29 (25), 7655-7660, DOI: 10.1021/la4009703

Simoncini, E., Virgo, N., Kleidon, A., Quantifying drivers of chemical disequilibrium: theory and application to methane in the Earth’s atmosphere, Earth Syst. Dynam., 4, 317-331, 2013. doi:10.5194/esd-4-317-2013.

T. Grassi, S. Bovino, D. R. G. Schleicher, D. Seifried, J. Prieto, E. Simoncini, F. A. Gianturco, KROME – a package to easily embed the chemistry in astrophysical simulations. MNRAS, vol. 439, 3, 2386 – 2419.

Russell, M.J., Nitschke, W. & Branscomb, E. 2013, The inevitable journey to being. Phil. Trans. R. Soc. Lond. B 368: 20120254.


4th TDE Focus Group Workshop: October 22 – 23, 2012, Parque de las Ciencias, Granada (Spain). This workshop contained sessions on Planetary Habitability, Emergence of Bioenergetics, a Young Participants section for local student presentations, and a field trip to the Rio Tinto.

3rd TDE Focus Group discussion meeting: April 2012 Astrobiology Science Conference. Topics included life’s far-from-equilibrium “free energy converters”, or “engines”. The meeting was well attended and TDE membership increased.

Shawn E. McGlynn, Isik Kanik, Michael J. Russell. Peptide and RNA contributions to iron-sulphur chemical gardens as life’s first inorganic compartments, catalysts, capacitors and condensers Phil Trans R Soc A. 2012, 370 (1969): 3007-3022.DOI:10.1098/rsta.2011.0211.


The 2nd TDE Focus Group Workshop was hosted at the Osservatorio Astrofisico di Arcetri (Galileo’s House) in Florence (Italy), on September 12-14. Its main goal was to discuss the submission of the proposals discussed in the previous Workshop in Madrid to either US or European Funding Opportunities.

The Thermodynamics, Disequilibrium and Evolution Focus Group held their first organizational meeting from March 1-3, 2011 at the Centro de Astrobiología in Madrid, Spain. A report and abstracts from the meeting are available here.