EXOA5 | Mineral surfaces in the origin and detection of Life on Earth and beyond


Mineral surfaces in the origin and detection of Life on Earth and beyond
Co-organized by TP
Convener: Electra Kotopoulou | Co-conveners: Albert Rimola, Vassilissa Vinogradoff
| Thu, 12 Sep, 08:30–10:00 (CEST)|Room Neptune (Hörsaal D)
| Attendance Thu, 12 Sep, 10:30–12:00 (CEST) | Display Thu, 12 Sep, 08:30–19:30
Orals |
Thu, 08:30
Thu, 10:30
Mineral surfaces might have played a pivotal role in the concentration, oligomerization, and compartmentalization of biologically relevant organic molecules, shielding them from radiation and hydrolysis. Concurrently, abiotic mineral precipitates known as biomorphs are able to mimic microbial cells and biologic remnants both morphologically and chemically. Join us in this session as we explore the dual role of minerals in igniting prebiotic chemical reactions and in hindering the detection of Life on Earth and Beyond. We welcome contributions focusing on reactions of mineral and/or metal surfaces with organic molecules in early Earth conditions and in extraterrestrial settings, such as interstellar media, icy moons, cometary environments and others. Topics can include both experimental and computational work tied to: i) adsorption processes and chemical reactivity of biomolecules on mineral surfaces, ii) hydrothermal alteration of organic matter in presence of minerals, iii) vesicle and protocell formation assisted by minerals, iv) the role of minerals/metals in the production of protometabolic reaction networks, v) mineral self-organized patterns and biomorphs that obscure the detection of true biosignatures and Life traces, including examples from laboratory experiments and field studies.

Orals: Thu, 12 Sep | Room Neptune (Hörsaal D)

Chairpersons: Electra Kotopoulou, Vassilissa Vinogradoff
On-site presentation
Dieter Braun

We will only fully understand the origin of life when we can recreate it in the laboratory. I report on our latest progress in building an autonomous evolution machine. A first step towards molecular evolution is the assembly of RNA from single nucleotides. We found that a moderate temperature difference at an air-water interface is an ideal micro-reactor for this process. The fluctuating interface continuously forms new dry spots by evaporation, driving the ring-opening polymerization of 2',3'-cyclic nucleotides toward RNA strands [1] and their length selective accumulation [2], including sequence-dependent phase transitions [3], showing fast evolution for DNA model systems [4] and accumulating prebiotic molecules by a thermal subsurface network [5]. The reaction only required a moderate alkaline pH and operated in a wide range of temperatures (4-80°C). The propagation of information is critical. Under the same pH conditions as above, we found templated ligation of RNA strands with 2',3'-cyclic ends. We see that both the formation and ligation is enhanced by amino acids. Surprisingly, the interface setting also shows signatures of modern cell biology: RNA is encapsulated into vesicles when lipids are added [2]. Even the components of modern cells assemble at the interface: a highly diluted PURE system accumulated at the air-water interface, triggering the expression of proteins such as GFP. Thus, interfaces control a remarkable variety of key steps in the evolution of life, making us optimistic that a prebiotic evolutionary machine can be created in the laboratory sooner rather than later.

[1] ChemSystemsChem doi.org/10.1002/syst.202200026 (2022)
[2] Nature Chemistry, doi.org/10.1038/s41557-019-0299-5 (2019)
[3] PNAS doi.org/10.1073/pnas.2218876120 (2023)
[4] Nature Physics doi.org/10.1038/s41567-022-01516-z (2022)
[5] Nature doi.org/10.1038/s41586-024-07193-7 (2024)

How to cite: Braun, D.: Shaping early molecular live by physical selection pressures, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-245, https://doi.org/10.5194/epsc2024-245, 2024.

On-site presentation
Severin Wipf, Ruben Nitsche, Zeba Sultana, David Burr, Janina Drauschke, Florence Hofmann, and Andreas Elsaesser

In the search for organic compounds associated with the origin and self-preservation of lifeforms in our solar system, inorganic materials are widely recognized as an important factor influencing the chemical stability of such organic compounds, so called biosignatures, under hostile space conditions like extreme temperature, pressure and radiation[1]. Here, spaceborne experiments and laboratory simulations play a crucial role to investigate the underlying interaction mechanisms of organic compounds and specific inorganic materials [2-4] in order to support the efforts of biosignature search by space missions [5, 6]. As next-generation spaceborne experiments, OREOcube (Organics Exposure Orbit cube) and ExocubeChem (Exposure of organics/organisms cube Chemistry) will be mounted on the outside of the International Space Station in 2026, enabling the exposition of biosignatures in and inorganic materials to elevated levels of electromagnetic radiation in the low Earth orbit for approxiimately 6 months. Both experiments will measure the photostability of organic molecules spectroscopically with robust, miniaturized and space-qualified spectrometers; while OREOcube will make use of an ultraviolet-visible (UV-VIS) spectrometer using the sun as light source, ExocubeChem will utilize a Fourier-transform infrared (FTIR) spectrometer with an integrated Globar to track structural changes of organic compounds and provide detailed information about their kinetics and photochemical evolution. The UV-Vis spectrometer of OREOcube covers a wavelength range of 200-1100nm while the IR spectrometer of ExocubeChem detects molecular vibrations in the 2.5-12µm range. To enable such in-situ measurements in space, the samples will be prepared as thin films of several nanometer up to thicknesses of some micrometer on Magnesium Fluoride (MgF2) substrates with high transparency for electromagnetic radiation from the UV- up to the mid-infrared wavelength range (approximately 120 to 8500 nm). To obtain uniform sample films, the organic and inorganic molecules will be deposited by controlled thermal evaporation or pipetting onto the MgF2 substrates which then can be hermetically sealed in specially designed gas tight cells, allowing control of different gas atmospheres and pressures. In this way, the organic/inorganic thin films can be exposed to specific gas mixtures giving the possibility to mimic different planetary atmospheres and the development of gaseous photolytic products of the sample species can be detected. The sample cell design and parts of the experimental setups are a heritage of the O/OREOS (Organism/Organic Exposure to Orbital Stresses) nanosatellite[7], optimized for spectroscopic measurement in space. Supportively, samples from OREOcube and ExocubeChem will be returned to the Earth, opening the possibility for further advanced post-flight anylsis of the samples. Additional microscopy and in-depth chemical analyses will provide a deeper understanding of the astrochemical processes undergone by the organic compounds and the impact of inorganic surfaces on their photochemical stability.

The ongoing preparation process of OREOcube and ExocubeChem includes the final selection of the sample species, considered to be most interesting combination of biosignatures and inorganic material in terms of relevance to the origin of lifeforms, photo-stabilization and preservation effects. In this context, we constructed a Mars simulation chamber at Freie Universitaet Berlin, which is designed to be compatible with the experimental design of OREOcube and ExocubeChem. The sample species, contained in the gas tight cells described above, can be exposed to the Martian surface temperature and atmospheric conditions (with the possibility of simulating atmospheric humidity) and subjected to simulated solar light irradiation with UV-light intensities which are modeled on those on the Martian surface environment. A fully automated measurement system using prototypes of the UV-Vis and FTIR-spectrometer of OREOcube and ExocubeChem can provide detailed information about the photochemical evolution and kinetics at 5-hour intervals without interfering with the experimental process.

Several experiments have been carried out to examine which organic/inorganic compounds are appropriate for the OREOcube and the ExocubeChem experiments, including the suitability of their chemical composition to the different spectroscopic methods. In a first set of experiments, we investigated the photochemical interactions of the proteinogenic amino acid alanine and the Martian soil analogue montmorillonite clay; we intercalated the amino acid into the interlayers of the montmorillonite, forming a so called organoclay. The results, in short, indicate that the alanine is photochemically unstable under Mars-like UV-radiation and would require millimeter-thick clay layers as sunshield to persist for extended periods of time. But, interestingly, the clay matrix is capable to confine gaseous carbon dioxide (a photolytic byproduct of the alanine decay) in its interlayers, indicating the past existence of an organic compound within the clay. This confinement process, however, has to be further analyzed with addressing the desorption rate of the carbon dioxide from the clay. In another, recent series of experiments, the photostability of biosignatures such as pigments (beta carotene and quercetin) or metal-porphyrins on iron oxide (FexOx) surfaces was investigated. Pigments play a key role in photoautotrophic metabolism and are potent scavangers of (UV-induced) free radicals [8], porphyrins are photochemically robust and an unambiguous indicator of biological activity [9] and iron oxides have found to be abundant on the Martian surface [10]. Preliminary results suggest, that the oxidation state of iron impacts the photostability of the organic compounds.

Further experiments with other classes of biosignatures such as polycyclic hydrocarbons and quinones in combination with inorganic materials found on the Martian surface such as titanium oxides (TiO2), manganese oxides (MnOx) and mineral clays are scheduled for the second half of 2024.   




1) Kopacz, N., et al., Icarus, 2023. 394.

2) Elsaesser, A., et al., Acta Astronautica, 2020. 170: p. 275-288.

3) Baratta, G.A., et al., Astrobiology, 2019. 19(8): p. 1018-1036.

4) Stalport, F., et al., Astrobiology, 2019. 19(8): p. 1037-1052.

5) Enya, K., et al., Life Sci Space Res (Amst), 2022. 34: p. 53-67.

6) Parker, E.T., et al., Geochimica Et Cosmochimica Acta, 2023. 347: p. 42-57.

7) Ehrenfreund, P., et al., Acta Astronautica, 2014. 93: p. 501-508.

8) Baque, M., et al., Science Advances, 2022. 8.

9) Suo, Z., et al., Astrobiology, 2007. 7(4): p. 605-15.

10) Morris, R.V., et al., Journal of Geophysical Research: Planets, 2006. 111(E12).



Ministry of Economics and Energy
(DLR, grants 50WB1623 and
50WB2023). Volkswagen Foundation and Freigeist Program.


How to cite: Wipf, S., Nitsche, R., Sultana, Z., Burr, D., Drauschke, J., Hofmann, F., and Elsaesser, A.: Photochemical Stability of Organic Compounds in Mineral Matrices and Metal Oxide Surfaces in Space: In-situ Spectroscopy on the International Space Station and Laboratory Simulation Experiments, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-983, https://doi.org/10.5194/epsc2024-983, 2024.

On-site presentation
Coline Serra, Vassilissa Vinogradoff, Olivier Grauby, Grégoire Danger, and Fabrice Duvernay

Introduction: Asteroids are primitive bodies formed from the first solids and organic matter (OM) present in the protoplanetary disc. The study of a particular class of meteorites, the carbonaceous chondrites (CC), derived from small, undifferentiated asteroids considered primitive, has demonstrated that some of them have undergone episodes of aqueous alteration. The mineralogical assemblage of the chondrite provides evidence of aqueous alteration. The formation of secondary minerals, such as phyllosilicates, can be observed. These CC can contain up to 4wt% of OM, some of which is in the form of diffuse OM intercalated in the phyllosilicates 1,2. There are many questions surrounding the history of this OM: to what extent has the OM evolved during this alteration within these mineral assemblages? Does this alteration explain the molecular diversity found in these objects today? Did the presence of OM influence the paragenesis obtained at the end of the alteration process? The co-alteration of OM and minerals under hydrothermal conditions represents a complex set of interactions that has received only limited attention in previous research. This study aimed to investigate these questions by experimentally simulating alteration conditions in the laboratory using model organic and mineral materials.

Methods: Experiments have been designed to investigate the chemical and mineralogical evolution of a hypothetical initial chondritic material exposed to hydrothermal conditions simulating asteroidal evolution. The objective of these experiments is to investigate the interactions between OM and minerals, taking into account the initial alteration conditions that integrate OM and primary minerals that may have been accreted within asteroids.

The organic material used in these experiments is hexamethylenetetramine (HMT), chosen as a model for interstellar organic compounds. This molecule (C6H12N4)  constitutes about 40wt% of the organic residues recovered in interstellar ice experiments 3. The selected silicates belong to the olivine and feldspar families, as they are considered primary minerals in asteroids and are observed in the least altered chondrites 4. To further increase the mineral complexity of our study, troilite (FeS), an iron sulfide commonly observed in weakly altered meteorites, was also introduced as a model iron mineral 4,5. The experiments consist of different compositions of HMT with minerals for different durations ( 1 to 100 days) under anoxic conditions at 80°C. We experimented the co-evolution of each mineral alone with the HMT and of a mixture of the three minerals in a ratio of 2:1:2 (peridot:troilite:feldspar) with the HMT.

The mineral fraction was analysed by elemental analysis, infrared spectroscopy, electron microscopy and X-ray diffraction analyses. The diversity of organic compounds formed from HMT was characterised by gas chromatography coupled to mass spectrometry (GC-MS) and infrared spectroscopy.

Results and Discussion: For an initial HMT concentration of 30 mM, we observed different decrease over time depending on the presence and nature of minerals. The degradation of HMT was the faster in the presence of troilite with almost 50% of HMT degraded after 1 day. On the contrary, in the presence of feldspar, the lowest HMT consumption was observed even after 100 days. For peridot and the mixture of minerals, the degradation is comparable to that observed in the absence of minerals, although it occurs more rapidly over extended periods (100 days).

We have characterized by GC-MS, a wide range of chemical families produced by the degradation of HMT under hydrothermal conditions. These include carboxylic acids, diols, ester derivatives, cyanides, amides and N-bearing aromatics. We chose to focus on the amides because they dominated in all experiments, especially in the first 10 days and their formation mechanism from HMT degradation can be easily explained. The presence and nature of the minerals have a crucial influence on the formation of amides. While in some cases, the mineral tends to slow down their formation (HMT alone compared to HMT with peridot, feldspar and complex mixture), the presence of troilite clearly favours their synthesis, but only for formamide derivatives. At longer time (100 days), amide abundance is highest with peridot (Figure 1).

The in-situ transformations of minerals also influence the pH conditions and the release of metallic ions. We were able to identify the presence of many organic salts and chelates, which probably altered the reactivity of the system. The primary mineral has indeed undergone partial transformation into secondary phases, including amorphous silicate, phyllosilicates, or oxides (for troilite samples). Under our alteration conditions, primary minerals were transformed into secondary minerals similar to those observed in CCs 4. Nevertheless, the presence of OM has affected the formation and composition of phyllosilicates, especially from peridot. We observed differences in the nature of the phyllosilicates formed, particularly at short alteration times (<10 days). In addition, the formation of secondary phases such as phyllosilicates, can also result in the adsorption of OM, thereby rendering it less available for future reactivity.

Overall, the evolution of the organo-mineral system cannot be reduced to the sum of the two systems. In fact, the two materials interact and evolve altogether during the alteration process. Moreover, the greater the initial diversity of the organo-mineral system (comprising multiple minerals and OM), the more complex it becomes, and novel and unexpected results are obtained in comparison to the binary system. The results of our experiment simulations clearly demonstrated the significant impact that both phases can have on each other. It was observed that a wide range of molecular diversity is formed under aqueous conditions, which depends on the presence and nature of the minerals. Concurrently, the OM influences the formation of secondary mineral phases.

Aknowledgements: We  acknowledge support from the Agence Nationale de la Recherche (ANR 22-CE49-0007 284 ORGAMISS – PI V. Vinogradoff). We thank Daniel Ferry with IR measurements at CINAM and  Gregory Excoffier (Spectropole of the Fédération des Sciences Chimiques Marseille, Aix Marseille University) for his help with elemental analysis.


(1)           Le Guillou et al., Geochimica et Cosmochimica Acta 2014, 131, 368–392. https://doi.org/10.1016/j.gca.2013.11.020.

(2)           Le Guillou et al., Geochimica et Cosmochimica Acta 2014, 131, 344–367. https://doi.org/10.1016/j.gca.2013.10.024.

(3)           Caro et al., A&A 2003, 412 (1), 121–132. https://doi.org/10.1051/0004-6361:20031408.

(4)           Brearley, Meteorites and the early solar system II 2006, 943, 587–624.

(5)           Herndon et al., Nature 1975, 253 (5492), 516–518. https://doi.org/10.1038/253516a0.


How to cite: Serra, C., Vinogradoff, V., Grauby, O., Danger, G., and Duvernay, F.: Co-evolution of organic and mineral phases during hydrothermal alteration of a simulated carbonaceous asteroid., Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-244, https://doi.org/10.5194/epsc2024-244, 2024.

On-site presentation
Stefano Pantaleone, Niccolò Bancone, Rosangela Santalucia, Marta Corno, Albert Rimola, Lorenzo Mino, Nadia Balucani, and Piero Ugliengo

Asteroids are the most ancient bodies of a planetary system, mostly formed during the accretion of the protoplanetary disk. They can be made of either rocky and metallic materials, and they are sources of important species which are fundamental for the emergence of life on planets. In our history, during the heavy late bombardment (4.0−3.8 Gya ago), a large quantity of meteorites (the asteroids that impact a planet) fall onto the earth crust, bringing several interstellar complex organic molecules, as well as other species (like phosphorus), produced during the early stages of the solar system formation.1 In recent years we have carried out periodic quantum mechanical simulations on forsterite (Mg2SiO4) and schreibersite (Fe2NiP) as archetype of rocky and iron meteorites, respectively. In particular, the former was studied through a synergistic interaction between experiments (infrared spectroscopy and high-mass resolution spectrometry) and atomistic simulations, elucidating the reactivity of HCN towards its polymerization, up to the formation of adenine, one of the DNA components.2,3 The latter system is a source of reactive phosphorus that, from the interaction with water, undergoes corrosion with the formation of oxygenated phosphorus compounds. In our work, we demonstrated the favorable exergonic formation of phosphates and, moreover, that such phosphates are in turn activated by the surface to phosphorylate other molecules, like sugars and nucleobases.4,5,6

[1] M. Pasek, D. Lauretta, Origins Life Evol. Biospheres 2008, 38, 5−21
[2] N. Bancone, S. Pantaleone, P. Ugliengo, A. Rimola, M. Corno, Phys. Chem. Chem. Phys. 2023, 25, 26797-26812
[3] R. Santalucia, M. Pazzi, F. Bonino, M. Signorile, D. Scarano, P. Ugliengo, G. Spoto, L. Mino, Phys. Chem. Chem. Phys. 2022, 24, 7224-7230
[4] S. Pantaleone, M. Corno, A. Rimola, N. Balucani, P. Ugliengo, ACS Earth Space Chem.  2021, 5, 7, 1741–1751
[5] S. Pantaleone, M. Corno, A. Rimola, N. Balucani, P. Ugliengo, J. Phys. Chem. C 2022, 126, 4, 2243–2252
[6] S. Pantaleone, M. Corno, A. Rimola, N. Balucani, P. Ugliengo, ACS Earth Space Chem. 2023, 7, 10, 2050–2061

How to cite: Pantaleone, S., Bancone, N., Santalucia, R., Corno, M., Rimola, A., Mino, L., Balucani, N., and Ugliengo, P.: Iron and rocky meteorites: a reservoir of prebiotic bricks of life, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1177, https://doi.org/10.5194/epsc2024-1177, 2024.

On-site presentation
Francesco Panico, Alessandro Minguzzi, Alberto Vertova, and Michael Russell

More than a century has passed since the hypothesis was first proposed that primordial biological molecules could have formed from non-biological material with the input of some form of energy. Great efforts have been made to test possible energy sources in various environments and to determine whether the abiogenesis of biological molecules is possible. Among all the theories, the one involving hydrothermal vents has recently captured particular attention because it is based on the idea that the reduction of CO2 and the initiation of a proto-metabolism could have occurred by exploiting a life-like thermodynamic disequilibrium on mineral structure that shows structural and compositional similarities with some catalytic centre of enzimes.1–3

Hydrothermal Vent are geological formation generated from the upwelling of geothermal fluids into the ocean, there are two main types of HTV: black smokers (acidic ones) and white smokers (alkaline ones). In the Archean era Alkaline Hydrothermal Vent were generated by the reaction between alkaline (pH 10-11), warm and hydrogen rich fluids with the ocean rich in CO2 (acidic 10-11) and metal ions such as Fe, Ni, Zn, Co, Mn; here at the mixing point a mineral barrier precipitate, composed mainly of iron oxide and hydroxide, green rust and iron sulphide. Across this mineral membrane an electrochemical potential difference is generated, because of the disparity in pH and redox species between the inner and outer sides of the vent, this thermodynamic disequilibrium can be dissipated by coupling two opposite reactions: CO2 reduction and H2 oxidation, the two semireaction take place on the opposite sides of the same mineral structure but in two different environments: the first acidic, the second alkaline. 4

Electrochemistry applied to the study of the behaviour of mineral materials from hydrothermal vents is a valuable tool because it allows for a precise investigation of the reactivity of material surfaces and correlates it with their electronic structure. 5

A hydrothermal vent system can be modelled as a short-circuited fuel cell, with a continuous flow of reactants to the electrodes. These electrodes are made of the material that forms the barrier and are located in two different environments: the first electrode functions as a cathode for the reduction of CO2 in an acidic environment, while the second functions as an anode for the oxidation of hydrogen (or other molecules) in an alkaline environment. An electric current is recorded between the two short-circuited electrodes. This coupling of reactions can be represented in an Evans diagram, analogous to a corrosion process.

Figure 1. Evans diagram in various condition

Figure 2. Short circuited fuel cell model of AHTV

In our laboratory, we developed a technique for synthesizing Mackinawite (FeSm) and Violarite (FeNi2S4). The samples have been characterized using spectroscopic, microscopic, and electrochemical methods. Using these materials, we have prepared electrodes for testing. A series of electrolysis experiments have demonstrated that these materials can electrochemically reduce CO2 at negative potentials as -1.2 V, producing formic acid, methanol, and carbon monoxide. The efficiency of this reaction decreases significantly when less extreme potentials are applied.


Figure 3. Production of formic acid and methanol during a potentiostatic electrolysis on Mackinawite or Violarite.

The behaviour of the electrodes was studied by recording Tafel plots (log(I) vs E) and creating an Evans diagram. This diagram illustrates the operational conditions of pH, catalytic material, and reaction environment under which it is possible to couple the CO2 reduction and hydrogen oxidation reactions effectively. Subsequently, the short-circuited fuel cell was constructed, allowing for the measurement of the current flow (which is proportional to the reaction rate and indicates the cell's polarity) and the electric potential at which the coupled reactions occur.

The results indicate that once the short-circuited fuel cell is assembled, in the absence of reactants and without a pH difference between the two compartments, no current is registered, suggesting that no reaction is occurring. However, upon introducing the CO2 and H2 reactants into their respective compartments, a pH gradient (6.5 vs 8.8) is established. Under these conditions, a reaction current is observed, with its direction indicating reduction at the pole containing CO2 and oxidation at the pole with H2. The potential at which this coupling occurs, on the synthesized metal sulphides materials, is -0.03 V vs SHE (@ pH 6.5), a value too positive to promote the CO2 reduction reaction. The limiting factor in this setup is the anodic reaction, so other conditions have been tested for improving the catalytic activity of the anode, changing electrolyte composition and pH, flux of reactant and even the composition of the electrode itself. For example, using platinum as the anode (a material known for its catalytic properties in reactions involving hydrogen), a coupling potential of -0.44 V is observed, a value within the range where the reduction reaction of CO2 at the cathode can occur.

This approach to measurement and interpretation of Alkaline Hydrothermal Vent functioning represents, in our opinion, a groundbreaking development in the field of studies on this topic. The future challenge lies in identifying the optimal operational conditions that accurately simulate the real environment of an alkaline hydrothermal vent on the Archean ocean floor, capable of facilitating a spontaneous reduction reaction of CO2.


1.Russell, M. J. Green rust: The simple organizing ‘seed’ of all life? Life vol. 8 Preprint at https://doi.org/10.3390/life8030035 (2018).

2. Branscomb, E. & Russell, M. J. Frankenstein or a Submarine Alkaline Vent: Who is Responsible for Abiogenesis?: Part 2: As life is now, so it must have been in the beginning. BioEssays vol. 40 Preprint at https://doi.org/10.1002/bies.201700182 (2018).

3. Russell, M. J., Nitschke, W. & Branscomb, E. The inevitable journey to being. Philosophical Transactions of the Royal Society B: Biological Sciences 368, (2013).

4. Hudson, R. et al. CO2 reduction driven by a pH gradient. Proc Natl Acad Sci U S A 117, 22873–22879 (2020).

5. Nitschke, W. et al. Aqueous electrochemistry: The toolbox for life’s emergence from redox disequilibria. Electrochemical Science Advances vol. 3 Preprint at https://doi.org/10.1002/elsa.202100192 (2023).


How to cite: Panico, F., Minguzzi, A., Vertova, A., and Russell, M.: A novel electrochemical approach to the CO2 reduction in Alkaline Hydrothermal Vent, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1068, https://doi.org/10.5194/epsc2024-1068, 2024.

On-site presentation
Delfina P. Henriques Pereira, Giuseppe Peyroche, Oskari Lehtinen, Tuğçe Beyazay, Harun Tüysüz, and Martina Preiner

We can connect the metabolism of the first cells on Earth (Last Universal Common Ancestor, LUCA) to its geochemical roots through top-down comparative bioinformatics[1] and through bottom up geochemical laboratory studies, using minerals and inorganic redox partners (H2, metal ions) as predecessors of enzymes [2]. Our aim is to connect central metabolic cofactors and enzymatic reactions that were present in LUCA to early Earth geochemical reaction partners in order to better understand the transition from environmental reactions to genetically encoded metabolic functions. The hypothesis: cofactors are the missing link between abiotic and biotic (enzymatic) catalysis.

In the presented studies, we focus on bridging abiotic and biotic hydrogen/electron transfer. Hydrogen gas, H2, is generated in various geochemical settings, among them serpentinization, a water-rock interaction process during which iron-containing minerals transfer electrons to the protons of water. H2 is also the electron donor for the most ancient route of biological CO2 fixation, the acetyl-CoA pathway. In metabolism itself, H2 is being transformed into biochemical electron donors, cofactors such as the dinucleotide NADH which can be seen – simply put – as hydride (H-) donors. We successfully activated hydrogen on minerals found in serpentinizing systems to reduce NAD+ to NADH under aqueous conditions [3].We transferred these principles onto other biochemical electron acceptors such as flavins and have furthermore shown unexpected mechanistic differences between the reduction of di- and mononucleotides.

Our results establish a connection between central reactions in metabolism and abiotic, geochemical catalysis with hydrogen as a common denominator.






[1]       M. C. Weiss et al. (2016) Nat. Microbiol. 1, 16116.

[2]       M. Preiner et al. (2020) Nat. Ecol. Evol. 4, 534–542.

[3]       S. Q. Lang, et al. (2010) Geochim. Cosmochim. Acta. 74, 941–952.

[4]       D. P. Pereira et al. (2022) FEBS J. 289, 3148–316.



Keywords: hydrogen ● cofactors ● minerals ● catalysis ● serpentinization

How to cite: Henriques Pereira, D. P., Peyroche, G., Lehtinen, O., Beyazay, T., Tüysüz, H., and Preiner, M.: Organic cofactors as connection between minerals and protometabolism?, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1327, https://doi.org/10.5194/epsc2024-1327, 2024.


Posters: Thu, 12 Sep, 10:30–12:00

Display time: Thu, 12 Sep 08:30–Thu, 12 Sep 19:30
Chairpersons: Albert Rimola, Electra Kotopoulou
On-site presentation
Simon Gouzy, Van T. H. Phan, Benjamin Rondeau, Vassilissa Vinogradoff, Boris Chauviré, Pierre Beck, Gerhard Franz, Vladimir Khomenko, and John Carter

Opal (amorphous silica, SiO2.nH2O) is a glassy and porous mineral formed by the aqueous alteration of silicate rocks through both weathering and hydrothermalism. Terrestrial and Martian observations, as well as fluid-rock alteration experiments, show that opal forms in various geological contexts (e.g., acidic volcanic traps, alluvial fans and deltas) and at different spatial scales (nanometers to kilometers). All these processes are related to planetary surface, involving near-atmospheric pressure and low temperature (0 to 200°C). By analogy with the Earth, such environments are also favorable to the presence and development of life forms.

Over geological time on Earth, several opal deposits formed in horizons containing ancient biological remains (e.g. wood, plant roots and seeds, vertebrate skeletons, etc.) that have been preserved by the silicification process. In the case of wood, several studies shown that this process does not seem to preserve significant amounts of OM, but rather act as a silica cast (Mustoe, 2023). Moreover, in these cases OM has never been visualized or qualified in-situ by detection methods such as spectroscopy but only observed after HF treatment (St. John, 1927) or roughly estimated by loss-on-ignition experiments (Mustoe, 2016).

In another hand, some opals (predominantly black) that do not exhibit evidences of macroscopic fossils, display discreet infrared signatures characteristic of organic matter (OM) (Banerjee & Wenzel, 1999; Herrmann et al., 2019). Such samples may indicate the existence of another type of interaction between OM and opal, distinct from the petrification of the dead organisms.

In order to document and characterize this OM-silica relationship, we conducted a non-destructive, in situ investigation using Micro-FTIR and AFM-IR on two samples from distinct localities where OM was suspected: pink opals from Quincy, France (found in 35 Ma-old lacustrine limestone) and black opal from Volyn, Ukraine (found in 1.5Ga to 550 Ma-old weathered magmatic rocks).

The FTIR and Micro-FTIR analyses indicate the presence of OM in both samples. The Quincy pink opal spectra show four well-defined peaks around 2855, 2880, 2930 and 2965 cm-1 characteristic of the stretching vibration of νs(CH2), νs(CH3), νas(CH2), and νas(CH3). A spatial variations investigation show that the OM bond’s signature varies positively with the intensity of the pink color. The spectra of Volyn black opal show only two well-defined peaks around 2855 and 2925 cm-1, characteristic of νs(CH2) and νas(CH2) respectively. These signatures are present in all black opal spectra with a similar relative intensity, indicating a diffuse and homogeneous distribution through the sample.

Micrometer-scale IR maps combined to topography images, both acquired by AFM-IR, reveal that the organics are clustered and localized preferentially in the micro- to nano-pores, at the pore-silica matrix interface in both opals. This spatial distribution suggests that the OM was trapped during the formation and deposition of the opals, rather than during a later event. This is supported the strong ability of silicic and polysilicic acids to bond with OM through the hydroxyl groups in solution, which is considered as a preliminary step in the petrifaction process of wood through templating (Leo & Barghoorn, 1976; Mustoe, 2023).

All these elements suggest that two processes are involved for the incorporation of OM in opal: 1) The precipitation of silica, leading to opal formation, may serve as a segregator of OM within the fluids through hydrogen bonding. 2) The mechanical deposition of silica nanograins and aggregated structure may serve as a local accumulator of OM.

Therefore, these observations make opal a promising candidate for preserving pristine organic matter, possibly related to life, over geological timescales on Earth and other planetary bodies, such as Mars, that experienced liquid water on their surface.


Banerjee, A., & Wenzel, T. (1999). Black opal from Honduras. European Journal of Mineralogy, 11(2), 401‑408. https://doi.org/10.1127/ejm/11/2/0401

Herrmann, J. R., Maas, R., Rey, P. F., & Best, S. P. (2019). The nature and origin of pigments in black opal from Lightning Ridge, New South Wales, Australia. Australian Journal of Earth Sciences, 66(7), 1027‑1039. https://doi.org/10.1080/08120099.2019.1587643

Mustoe, G. E. (2016). Density and loss on ignition as indicators of the fossilization of silicified wood. IAWA Journal, 37(1), 98‑111. https://doi.org/10.1163/22941932-20160123

Mustoe, G. E. (2023). Silicification of Wood : An Overview. Minerals, 13(2), 206. https://doi.org/10.3390/min13020206

How to cite: Gouzy, S., Phan, V. T. H., Rondeau, B., Vinogradoff, V., Chauviré, B., Beck, P., Franz, G., Khomenko, V., and Carter, J.: Organic matter in opal: in situ investigation with non destructive techniques, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-434, https://doi.org/10.5194/epsc2024-434, 2024.

Virtual presentation
Miguel Arribas Tiemblo and Felipe Gómez

The preservation of amino acids in the immediate martian surface is cut short by the intense UV irradiation it suffers. Most organic matter in and amino acids in particular are significantly degraded in short periods of time. For instance, glycine has been described to have a half-life of 250 hours aprox. under noon irradiation conditions (1). These very harsh conditons are imposed by UV as the principal degrading agent (2,3). More recent studies have further described the preservation of amino acids in a wide array of substrates, from clays to sulphatic minerals (4) as well as in the presence of oxychlorine salts (5), and it has been determined that many substrates can preserve amino acids successfully, be it though adsorption or UV attenuation, as is the case for clays and sulphates, respectively. Perchlorates do also hinder this preservation, but not to a point at which their recovery is impossible.

The main issue with these studies is that the amino acidic analysis has been carried through chromatographic techniques, which although extremely powerful, add steps and require sample extraction. To avoid this, we attempted to quantify the preservation of amino acids through raman spectroscopy. This approach is less sensitive than the previous ones, particularly in heterogeneous mixtures, but it allows for direct analysis of the surface of the samples, and is an instrument present in most current and future missions to Mars (6–9). To assess the feasibility and usefulness of raman spectroscopy for the identification of amino acids, we spiked five amino acids (His, Tyr, Phe, Met and Leu) into four regolith simulants (Olivine, MGS-1, MMS-2 and rock dust from Río Tinto, an acidic river in southern Spain) at a 1% w/w proportion. We then pelleted the mixtures and irradiated them in the UVB range for three days, or an accumulated dose of 40000 kJ/m2, that is, around 110 martian sols.

Aromatic amino acids, like tyrosine, histidine and phenylalanine, are extremely sensitive to UV damage. They also display the strongest raman signals. The raman signal in of these three amino acids in the irradiated samples was completely lost. Methionine, an S-bearing amino acid, appeared to be extremely sensitive to substrate damage and no raman bands could be reliably observed under any condition. Leucine, an aliphatic amino acid, did show a decrease in signal after irradiation, but it retained some signal, the only amino acid to do so. We also observed differences in preservation in different substrates, as unreactive ones like olivine and MGS-1 favoured the preservation and detection of raman bands, while MMS-2 and PRT, which are significantly more oxidative, generally masked or degraded most signals, even in unirradiated samples. Finally, we also observed an intense, 7-15 fold increase in the background fluorescence of the regolith simulants after irradiation. This further hindered the detection of organic raman bands and may be an issue in the interpretation of future raman spectra.

1. Ten Kate IL, Garry JRC, Peeters Z, Foing B, Ehrenfreund P. The effects of Martian near surface conditions on the photochemistry of amino acids. Planet Space Sci. 2006 Mar 1;54(3):296–302.

2. Garry JRC, Loes ten Kate I, Martins Z, Nørnberg P, Ehrenfreund P. Analysis and survival of amino acids in Martian regolith analogs. Meteorit Planet Sci. 2006;41(3):391–405.

3. Ten Kate IL, Garry JRC, Peeters Z, Quinn R, Foing B, Ehrenfreund P. Amino acid photostability on the Martian surface. Meteorit Planet Sci. 2005;40(8):1185–93.

4. Dos Santos R, Patel M, Cuadros J, Martins Z. Influence of mineralogy on the preservation of amino acids under simulated Mars conditions. Icarus. 2016 Oct 1;277:342–53.

5. Liu D, Kounaves SP. Degradation of Amino Acids on Mars by UV Irradiation in the Presence of Chloride and Oxychlorine Salts. Astrobiology. 2021 Jul 1;21(7):793–801.

6. Caffrey M, Boyd K, Gasway D, McGlown J, Michel J, Nelson A, et al. The Processing Electronics and Detector of the Mars 2020 SHERLOC Instrument. IEEE Aerosp Conf Proc. 2020 Mar 1;

7. Abbey WJ, Bhartia R, Beegle LW, Deflores L, Paez V, Sijapati K, et al. Deep UV Raman spectroscopy for planetary exploration: The search for in situ organics. Icarus. 2017 [cited 2023 Dec 1];290:201–14.

8. Rull F, Maurice S, Hutchinson I, Moral A, Perez C, Diaz C, et al. The Raman Laser Spectrometer for the ExoMars Rover Mission to Mars. https://home.liebertpub.com/ast. 2017 Jul 1 [cited 2024 Mar 21];17(6–7):627–54.

9. Tomba JP, Pastor JM. Confocal Raman Microspectroscopy: A Non-Invasive Approach for in-Depth Analyses of Polymer Substrates. Macromol Chem Phys. 2009 Apr 2 [cited 2024 Mar 21];210(7):549–54.

How to cite: Arribas Tiemblo, M. and Gómez, F.: Amino acid preservation under mars surface UV irradiation protected by martian regolith simulants., Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-332, https://doi.org/10.5194/epsc2024-332, 2024.

On-site presentation
Pamela Knoll

Abiotic precipitation typically conforms to the formation of geometric shapes. This is seen in the many small crystals from the fast nucleation in supersaturated solutions to the large faceted structures from the slower growth in more dilute environments. Across these nano to meter length scales, the morphological traits of flat faces and sharp edges persists from the self-assembly of either atoms or of larger nanoparticles and has guided the prevailing view of precipitation in the absence of life. The near equilibrium conditions for these crystallizing systems are in stark contrast to the products forming in complex physicochemical conditions within far-from-equilibrium settings. Under such environments, surprising structures and patterns emerge. These can be achieved experimentally as in the long-standing laboratory experiment producing hollow chemical gardens, the spatial organization of Liesegang rings, and, more recently, the biomimetic precipitation of biomorphs. Understanding the physics and chemistry governing these examples will pave the way for discovering potential new systems able to achieve similar results and inform the analysis of naturally occurring examples on Earth and other planetary bodies.

How to cite: Knoll, P.: Investigating Far-from-equilibrium Abiotic Precipitation, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-977, https://doi.org/10.5194/epsc2024-977, 2024.

On-site presentation
Alexandra Perron, Vassilissa Vinogradoff, Fabien Stalport, François Baudin, and Bénédicte Ménez

Introduction: The search for organic compounds of biological origin in extraterrestrial environments is one of the major objectives of space missions. However, the interpretations of the origins (biological or otherwise) of organic matter in extraterrestrial environments is a highly complex process. The same concern is encountered when probing for the oldest traces of life on Earth. The search for by-products of potential biological activity such as bio-minerals can be an interesting alternative to decipher biological from non-biological organic compounds. Many minerals of biological origin have been identified on present-day Earth, trapping organic compounds of biological origin, used as template for mineralisation [1], [2]. Therefore, it can be assumed that traces of biological activity could have been preserved more efficiently in the form of inorganic phases such as bio-minerals and potentially able to protect and preserve in their crystallographic structure, biological organic compounds.

Nevertheless, numerous studies also demonstrate the possibility of forming abiotic minerals by organo-mineralization (precipitated solely in the presence of organic molecules without any living organisms) [3], [4], [5]. On Earth, carbonate minerals have been widely produced by bio-, organo-mineralization as well as by inorganic mineralization processes throughout geological history. However, both bio- and organo-mineralization processes use organic compounds as nucleation sites for carbonation leading in both cases to organic-rich carbonates with occasionally similar characteristics [6]. Few studies have shown that the nature of organic compounds, including their physico-chemical properties but also their structural form (chirality) lead to the formation of organo-carbonates with various characteristics (e.g., mineralogies, morphologies) [4], [5], [7]. The presence of one or more COO- functional groups on molecules, which can form a weak bond with Ca2+ ions and thus induce carbonation, could have an influence on the properties of organo-carbonates produced.

The aim here is to investigate the formation of organo-carbonates in various environmental conditions and with various chemical compounds to assess the physico-chemical properties of a wide diversity of organo-carbonates. This could give us an insight into the carbonation mechanisms linked to the intrinsic properties of organic compounds, and enable us to study the impact of these organic compounds on the properties of the organo-carbonates. Data acquired on the organo-carbonates produced in this study are also compared with a dataset acquired on numerous abiotic carbonates and bio-carbonates, both natural and laboratory-synthesized [6], [8], with the aim of identifying relevant criteria for distinguishing carbonates according to their mineralization process and identify possible false positives biosignatures. 

Methods: Organo-carbonate precipitation was carried out using the ammonium diffusion method, where carbon dioxide and ammonium, derived from the spontaneous decomposition of ammonium carbonate, are gradually dissolved in an aqueous solution containing CaCl2 and amino acids. Experiments took place at room temperature for 20 days, in desiccators filled with silica gel, ammonium carbonate and petri dishes each containing 30 ml of aqueous solution. The organo-carbonates obtained were studied using a wide range of analytical techniques to investigate their physico-chemical properties. Morphologies were assessed by scanning electron microscopy, mineralogies and structural properties by X-ray diffraction and infrared spectroscopy, and thermal stability and organic content by differential thermal analysis and Rock-eval analysis.

Results: Experiments carried out with amino acids (various concentrations, with enantiomeric forms, inert or oxygenated atmospheres) produced organo-carbonates with different physico-chemical properties, such as different mineralogies (i.e., various proportions of carbonate polymorphs: calcite, aragonite, vaterite), morphologies (i.e., rhombohedral, spherical, needle-shaped with smooth or grooved surfaces), organic matter contents and thermal stabilities. These data were compared with results obtained on abiotic and bio-carbonates (~30 samples) acquired with the same instruments and the same analytical methods [6], [8]. Preliminary results obtained from the analysis of 3 organo-carbonates (precipitated with L-glutamine, L-glutamic acid, L-aspartic acid) show a wide diversity of physico-chemical properties. Each organo-carbonate samples have various proportions of carbonate polymorphs depending on amino acids, different morphologies (Fig. 1 - A, B, C) and a thermal decomposition at high temperatures (~815-820°C) closer to abiotic carbonates than to natural and laboratory-synthesized bio-carbonates (Fig. 1 - D).

Discussion: Based on the preliminary results acquired on few organo-carbonates, minerals can have various morphologies and surface textures occasionally similar to bio-carbonates (spherical or needle-shaped) or abiotic carbonates (rhombohedral). It is therefore undeniable that morphology cannot be the only criterion for distinguishing carbonates according to their mineralization process. However, the spherical shape of some organo-carbonates could be a characteristic linked to the nature of the organic compound used as an organic template for mineralization. According to the physico-chemical properties of organic compounds more or less weak bonds between the Ca2+ and, for example, the COO- groups of certain amino acids might have been formed. Whereas, on the contrary, rhombohedral shapes may imply a limited use of certain organic compounds as triggers for the carbonation. To conclude on this hypothesis, many organo-carbonates will have to be synthesized in the presence of various amino acids, but also with other organic compounds having different physico-chemical properties (e.g., sugars, alkanes). Comparison between the properties of organo-carbonates and carbonates produced by bio- and inorganic mineralization (e.g., thermal stability, Fig.1-D) could be used as a criterion to distinguish bio-carbonates from organo-carbonates. However, to be able to assert the origin of a mineral, it is necessary to identify other criteria to corroborate these observations and thus accurately distinguish these two processes.

Acknowledgements: We gratefully acknowledge the technical support of S. BORENSZTAJN for the scanning electron microscopy (UPC, PARI platform - IPGP), S. NOWAK for X-ray diffraction analysis (UPC, X-ray platform) and A. CHEVILLOT-BIRAUD for the differential thermal analysis (UPC, ITODYS).


[1] Tourney, J., & Ngwenya, B. T. (2009). Chemical Geology, 262(3-4), 138-146.

[2] Hoffmann, T. D., et al., (2021). Microbiology, 167(4), 001049.

[3] McMahon, S., & Cosmidis, J. (2022). Journal of the Geological Society, 179(2), jgs2021-050.

[4] Braissant, O., et al., (2003). Journal of Sedimentary Research, 73(3), 485-490.

[5] Xie, A. J., et al., (2005). Journal of Crystal Growth, 285(3), 436-443.

[6] Perron, A. , Paris, 2023.

[7] Wolf, S. E., et al., (2007). Angewandte Chemie International Edition, 46(29), 5618-5623.

[8] Perron, A., et al., (2023). Astrobiology, 23(4), 359-371.

How to cite: Perron, A., Vinogradoff, V., Stalport, F., Baudin, F., and Ménez, B.: Abiotic organo-minerals, a threat for identification of bio-minerals in hydrothermal systems and extraterrestrial environments, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1122, https://doi.org/10.5194/epsc2024-1122, 2024.

On-site presentation
Mingchuan Zheng, Silvana S. S. Cardoso, Herbert E. Huppert, Julyan H. E. Cartwright, and Alexander F. Routh

Chemical gardens refer to a class of plant-like self-assembling inorganic precipitate structures whose growth is driven by osmosis. They are thought to be related to hydrothermal vents and the origin of life. In this work, we have investigated the dynamical behaviour of chemical gardens grown in a horizontal Hele-Shaw cell from cobalt and manganese chloride with aqueous sodium silicate. It is found that the growth of the chemical gardens is well-described by a diffusion-controlled model. In reproducible time scales, the chemical gardens exhibit explosive fracture, which we attribute to osmosis-induced pressurisation. This is similar to osmotic lysis found in biological cells.

How to cite: Zheng, M., Cardoso, S. S. S., Huppert, H. E., Cartwright, J. H. E., and Routh, A. F.: Pellet-grown chemical gardens in horizontal planar confined geometry : Diffusion-controlled growth and osmotic fracture, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-253, https://doi.org/10.5194/epsc2024-253, 2024.