Europlanet Science Congress 2022
Palacio de Congresos de Granada, Spain
18 – 23 September 2022
Europlanet Science Congress 2022
Palacio de Congresos de Granada, Spain
18 September – 23 September 2022

TP15

Astrobiology is the study of whether present or past life exists elsewhere in the universe. To understand how life can begin in space, it is essential to know what organic compounds were likely available, and how they interacted with the planetary environment. This session seeks papers that offer existing/novel theoretical models or computational works that address the chemical and environmental conditions relevant to astrobiology on terrestrial planets/moons or ocean worlds, along with other theoretical, experimental, and observational works related to the emergence and development of Life in the Universe. This includes work related to prebiotic chemistry, the chemistry of early life, the biogeochemistry of life’s interaction with its environment, chemistry associated with biosignatures and their false positives, and chemistry pertinent to conditions that could possibly harbor life (e.g. Titan, Enceladus, Europa, TRAPPIST-1, habitable exoplanets, etc.). Understanding how the planetary environment has influenced the evolution of life and how biological processes have changed the environment is an essential part of any study of the origin and search for signs of life. Earth analogues experiments/instruments test and/or simulation campaigns and limits of life studies are included as well as one of the main topics of this session. Major Space Agencies identified planetary habitability and the search for evidence of life as a key component of their scientific missions in the next two decades. The development of instrumentation and technology to support the search for complex organic molecules/sings of life/biosignatures and the endurance of life in space environments is critical to define unambiguous approaches to life detection over a broad range of planetary environments.

Co-organized by OPS/SB/EXOA
Convener: Felipe Gómez | Co-conveners: Nuria Rodríguez-González, Sohan Jheeta, Frank Trixler, Rosanna del Gaudio
Orals
| Mon, 19 Sep, 10:00–11:30 (CEST), 15:30–18:30 (CEST)|Room Albéniz+Machuca
Posters
| Attendance Mon, 19 Sep, 18:45–20:15 (CEST) | Display Mon, 19 Sep, 08:30–Wed, 21 Sep, 11:00|Poster area Level 1

Session assets

Discussion on Slack

Orals: Mon, 19 Sep | Room Albéniz+Machuca

Chairpersons: Felipe Gómez, Nuria Rodríguez-González, Sohan Jheeta
10:00–10:20
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EPSC2022-254
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solicited
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MI
Juan Perez-Mercader

Experimental progress made during the last decade in dynamical self-assembly and its chemical implementation can be used to provide experimental examples of biochemistry-free autopoietic systems that emerge from homogeneous and isotropic solutions under selected environmental conditions. These simple emergent vesicular structures and systems self-assemble and, then in aqueous media, using conformational information, metabolize, self-reproduce, compete and evolve by adaptive or non-adaptive means. They also are chemo and phototactic. These systems can be implemented in the chemistry laboratory. They can be thought of as very primitive proto-cellular systems capable of evolving. Their information handling and metabolism use RAFT (Reversible Addition Fragmentation Transfer) polymerization chemistry, their reproduction is by sporular seeds and results from the combination of both environment induced degradation and hydrodynamic instability of the autonomously created amphiphiles and their metastable self-assembled membranes. Their evolution involves the adaptive interaction between environment, population and the feedback loops between the two highly selective chemistries that are combined in the system: “click chemistry” and (RAFT) polymerization induced self-assembly.

How to cite: Perez-Mercader, J.: From a Homogeneous Non-biochemical Soup to the Emergence of Fundamental Functions of Life, including Adaptation. Physics and Chemistry Working Together at micron scales, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-254, https://doi.org/10.5194/epsc2022-254, 2022.

10:20–10:35
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EPSC2022-141
Vassilissa Vinogradoff, Raphael Pepino, Vanessa Leyva, Lauryane Cazals, Coline Serra, Gregoire Danger, and Cornelia Meinert

 Introduction: Sugars are important molecules with high biological interest. Found in cometary-like analogs (Meinert et al., 2016), carbonaceous meteorites (Cooper et al., 2001; Furukawa et al., 2019), and likely on early Earth, sugars may have contributed as a source of molecules for the emergence of prebiotic systems on Earth. Hence, it is of prime importance to investigate their formation in conditions relevant to these environments, and particularly in the presence of minerals. For example, sugar formation is achieved through the formose reaction: the dimerization of formaldehyde, forming glycolaldehyde, which then by aldol reactions with another formaldehyde, will form successively higher sugar homologues. A catalyst is usually required for the first step, the formation of glycolaldehyde (typically calcium hydroxide). However, there is a lack of studies exploring the potential of minerals on the classical formose reaction (Gabel and Ponnamperuma, 1967; Haas et al., 2020) and in conditions representative of prebiotic environments. Here, we focus on the formation of sugars from formaldehyde via the formose reaction in aqueous solution using minerals, simulating conditions in which planetary surfaces could have evolved at the beginning of the Solar System.

Experiments and methods: Experiments took place in aqueous systems under anoxic atmosphere at 80 °C. We choose olivine as a model silicate, which is omnipresent in the solar system, and designed a series of experiments differing formaldehyde (F), glycolaldehyde (G), calcium hydroxide Ca(OH)2 (α) and olivine (O) compositions. We tested different combinations, O, F, FO, FG, FGO, Fα, FGα, for different durations up to 45 days. Formaldehyde (under the form of polyoxymethylene) was introduced with glycolaldehyde or calcium hydroxide at a weight ratio of 10/1 and olivine/formaldehyde also at a weight ratio of 10/1. The mixtures were loaded in closed cells under argon atmosphere in a glove box before being heated in an oven at 80 °C. We used Gas Chromatography-Mass Spectrometry (GC-MS) and GC×GC-TOFMS for the identification and quantification of sugars formed in the individual samples.

Results: Identification of sugars in the different samples was performed comparing retention times and relative mass spectra with those of reference standards (oses, polyols, sugar acids and deoxy sugars acids).

Abundance of sugars found in samples after 2 days of reaction are shown in figure 1. No sugars have been identified in samples F2, except minor contaminants from the derivatization protocol. In contrary, in the presence of olivine (sample FO2), 16 sugars have been identified and quantified based on reference standards, and many more peaks seen in the chromatograms are suspected polyolsbased on their mass spectra. We observed the same sugars in the FGO samples, while only a few of them are observed in the FG samples. Most importantly, olivine allowed the detection of C6 sugars after only 2 days of reaction, not observed in samples without olivine even after 45 days of hydrothermal reaction. When compared to experiments with the classical Ca(OH)2 catalyst, identical sugars are identified with olivine with highest abundances found for Ca(OH)2. For all samples, the diversity and quantity of sugars (mainly oses) decreased after 2 days of reactions, and mainly polyols remained in samples with olivine after 45 days.

Discussion: These experiments demonstrate that minerals may have played a crucial role in the chemical reactivity during evolution of chemical systems in aqueous environments. Here, sugars have been formed  through a mineral-assisted formose reaction leading to a high molecular diversity and sugar abundance after short reaction times, without any other classical catalyst. The silicate likely ensures the selection and stabilization of the C3-C4 sugars allowing rapid aldolisation to C6, unlike solutions without silicate. However, decomposition of sugars with time is inevitable; nonetheless, surprisingly polyol-sugars survive hydrothermal alteration with olivine on longer times. These experiments raise again the question of mineral impact on the organic evolution, even as simple as olivine, in conditions mimicking aqueous environments on planetary surfaces similar to prebiotic conditions on Earth (Vinogradoff et al., 2020).

References:   Cooper G. et al., (2001), Nature 414.

Furukawa Y. et al., (2019), Proc. Natl. Acad. Sci. 116.

Gabel N. W. and Ponnamperuma C. (1967), Nature 216.

Haas M. et al., (2020), Commun. Chem. 3.

Meinert C., et al., (2016), Science 352.

Vinogradoff V. et al., (2020) Geochim. Cosmochim. Acta 269.

 

How to cite: Vinogradoff, V., Pepino, R., Leyva, V., Cazals, L., Serra, C., Danger, G., and Meinert, C.: Mineral-catalyzed sugar synthesis under hydrothermal conditions, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-141, https://doi.org/10.5194/epsc2022-141, 2022.

10:35–10:50
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EPSC2022-86
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ECP
Elle Bethune, Charles S Cockell, Eleanor E.B Campbell, and Andrey Gromov

The appearance of the first microbial life on Earth coincided with the Late Heavy Bombardment, during which time a large amount of meteoritic material was accreted. A significant fraction of this material contained organic carbon of extra-terrestrial origin which likely survived atmospheric entry. It is therefore highly plausible these extra-terrestrial carbon compounds interacted with primitive microorganisms in some respect. Of the known extra-terrestrial carbon compounds found in meteorites, little is known about the effect of fullerenes and their derivatives on microbial communities. An anaerobic community is used in our studies as a model to infer how these compounds may have influenced the metabolic development of primitive microbes with respect to the environmental conditions on the early Earth.

Pristine high molecular weight fullerenes C60 and C70 appear to have no effect on the growth of anaerobic microorganisms when an additional carbon source is present. Community growth is significantly reduced when C60 is present as the sole carbon source and no intermediate breakdown products are detected with mass spectrometry. Some features observed with transmission electron microscopy indicate ingestion of small amounts of C60 may be occurring, however C60 and C70 remain to appear relatively inaccessible to anaerobic microbes.

The naturally occurring water-soluble C60 derivative, C60 fullerol, is inhibitory to the growth of this anaerobic community, particularly when exposed to ambient or short-wave UV light. The presence of these fullerene derivatives on the early Earth therefore may have had an inhibitory effect on the development of primitive microbes and added to the selection pressures driving metabolic evolution.

Current and future work focuses on simulating early Earth environmental conditions to produce naturally occurring fullerene breakdown products as potential sources of accessible carbon for primitive microorganisms. 

How to cite: Bethune, E., Cockell, C. S., Campbell, E. E. B., and Gromov, A.: Anaerobic Microbial Interactions with Fullerenes: Implications for the Use of Extra-terrestrial Organics by Life on Early Earth, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-86, https://doi.org/10.5194/epsc2022-86, 2022.

10:50–11:05
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EPSC2022-72
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ECP
Iva Vilovic, Dirk Schulze-Makuch, and René Heller

In our search for life in the Universe, it would be anthropocentric to assume that there are no planets more suitable for life than Earth. We call such planets ‘superhabitable’1. Some of the environmental conditions related to superhabitability are motivated astrophysically, while others are based on the varying habitability throughout Earth’s natural history2

Here we present our initial results in which we investigate potentially superhabitable conditions which, among other parameters, include K-dwarfs as host stars. To simulate the astrophysical condition of superhabitability, we obtained an LED solar simulator with a variable spectrum module which we adapted for our needs. As part of the theoretical preparations for our physical setup of the experiment in the lab chamber, we modeled the emission spectrum of a 4300 Kelvin K-dwarf star using the PHOENIX spectral library. We calculated the emission spectrum at the top of the planetary atmosphere of the hypothetical planet in the center of the star’s habitable zone, at a distance of ~0.44 AU, where it receives 0.6 times the solar effective flux, i.e. ~820 W/m2. Using Earth’s telluric spectrum we calculated for the first time the stellar spectrum of a K-dwarf star transmitted to the surface of a hypothetical habitable zone planet with an Earth-like atmosphere. We used this spectrum as a backbone for creating the LED spectral fit. As a test run, we built a small external-light-isolating chamber and are determining the responses of plant species (e.g. watercress) to the produced K-dwarf stellar spectrum in comparison to solar light.

At the same time we quantified the variations of habitability conditions during the natural history of Earth. Paleontological and geochemical records are key to the reconstruction of geological and atmospheric aspects that have affected Earth’s biosphere. We used these to understand how environmental tracers (e.g. surface temperatures, oxygen partial pressures and relative humidity) correlate with biological tracers (e.g. biomass production and biological diversity). Variations of the global average surface temperature in the Phanerozoic era have previously been demonstrated to be inversely correlated with biodiversity3,4. Here we show for the first time that periods with elevated oxygen partial pressures in the atmosphere correlate with increased biomass production but not biological diversity, whereas humid periods correlate strongly with biodiversity and to some extent with biomass. These results extend the previously established effect of surface temperature on biological diversity to a similar correlation with biomass, and stress the impact of oxygen and relative humidity on the biosphere. Our results help us to better understand how the modern biosphere could change in the future, especially in light of the rapid anthropogenic changes. Beyond that, such tracers could soon be measured on extrasolar planets with space-based observatories5–7, whose geo- or biological origin could be better interpreted using our results. 

Eventually we plan to apply theoretical climate-chemistry models to determine how life affects the biosignatures of a superhabitable planet around a K-dwarf host star by calculating synthetic transmission / emission spectra and atmospheric compositions, as it is vital to determine whether life that flourishes under such conditions can also be observable. These results will be used to provide a guide for space-based transit observations of extrasolar potentially habitable planets.

References

1. Heller, R. & Armstrong, J. Superhabitable Worlds. Astrobiology vol. 14 50–66 (2014).

2. Schulze-Makuch, D., Heller, R. & Guinan, E. In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World. Astrobiology 20, 1394–1404 (2020).

3. Mayhew, P. J., Jenkins, G. B. & Benton, T. G. A long-term association between global temperature and biodiversity, origination and extinction in the fossil record. Proc. Biol. Sci. 275, 47–53 (2008).

4. Song, H. et al. Thresholds of temperature change for mass extinctions. Nat. Commun. 12, 4694 (2021).

4. Krissansen-Totton, J., Garland, R. & Irwin, P. Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: A TRAPPIST-1e case study. Astron. J. (2018).

5. The LUVOIR Team. The LUVOIR Mission Concept Study Final Report. arXiv [astro-ph.IM] (2019).

7. Scott Gaudi, B. et al. The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Final Report. arXiv [astro-ph.IM] (2020).

How to cite: Vilovic, I., Schulze-Makuch, D., and Heller, R.: Earth’s varying paleoenvironment and experimental tests provide insights into superhabitabitable conditions on exoplanets, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-72, https://doi.org/10.5194/epsc2022-72, 2022.

11:05–11:20
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EPSC2022-495
Nicoletta La Rocca, Mariano Battistuzzi, Riccardo Claudi, Lorenzo Cocola, and Luca Poletto

Recently discovered Earth-like exoplanets are orbiting the Habitable Zone of M-dwarf stars, the most abundant and long-lived stars known in the Milky Way. Such stars have different spectral characteristics respect to the Sun, being less luminous and generating a light spectrum with a major component in far-red and infrared, while emitting very low in the visible. Many researchers discussed the possibility of oxygenic photosynthesis in these worlds, as the characteristics of M-dwarf stars do not seem suitable for most oxygenic photosynthetic organisms evolved on Earth to absorb the only visible light. However, no experimental research has been done testing organisms under simulated M-dwarf spectra. At the university of Padova, a collaboration between the Department of Biology, the Astronomical Observatory (INAF) and the Institute of Photonics and Nanotechnology (IFN-CNR) led to the construction and the development of a new experimental tool. The setup is composed by two main components: a Star Light Simulator, able to generate different light intensities and spectra, including those of M-dwarf stars and an Atmosphere Simulator Chamber where different gas compositions can be set, allowing to grow photosynthetic organisms under selected non-terrestrial conditions. We initially focused on cyanobacteria as target microorganisms, due to their extraordinary capacities to withstand every kind of environment on the Earth as well as their ability to acclimate to Far-Red light. We are now testing the responses of different species of microalgae and mosses by analysing their ability to acclimate to Far-Red light and M-dwarf simulated spectra.

How to cite: La Rocca, N., Battistuzzi, M., Claudi, R., Cocola, L., and Poletto, L.: Responses of eukaryotic photosynthetic organisms to simulated M-dwarf star light. , Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-495, https://doi.org/10.5194/epsc2022-495, 2022.

11:20–11:30
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EPSC2022-70
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ECP
Silvana Pinna, Emilie Werner, and Joseph Moran

In modern metabolism, phosphorylated compounds play a key role[1]. The informational molecules RNA and DNA are composed of phosphorylated units (nucleotides), and phosphorylation is also used as an activation mechanism for many metabolic processes, particularly through the universal energy currency adenosine triphosphate (ATP).

The deeply conserved nature of this reaction suggests an early origin of phosphorylation to drive metabolism. However, the non-enzymatic transfer of a phosphate group is challenging in water. Additionally, the poor geochemical accessibility of phosphate constrains the plausibility of phosphorylated compounds at the origin of life that are biologically relevant and have an appropriate reactivity in aqueous conditions.

Here, I report the phosphorylation of several biologically relevant molecules by an active metabolite-metal species that uses the prebiotically plausible molecule acetyl phosphate[2–5] as phosphate donor. Occurring in aqueous solution under mild prebiotic conditions, this work furthers the notion that ATP is universally conserved across life likely due to its formation being chemically favoured in aqueous solution that has recently been suggested[6].

 

References: 

[1] Westheimer, F. Why nature chose phosphates over arsenates. Science (1987). 13(4793): 3601–3608.

[2] Lipmann, F., Tuttle, L.C. Acetyl phosphate: chemistry, determination, and synthesis. J. Biol. Chem. (1944). 153: 571–582.

[3] de Duve, C. Blueprint for a cell: the nature and origin of life. (1991). Neil Patterson Publishers, Burlington.

[4] Schönheit, P., Buckel, W., Martin, W.F. On the Origin of Heterotrophy. Trends Microbiol. (2016). 24: 12–25.

[5] Whicher, A., Camprubí, E., Pinna S, Herschy B, Lane N. Acetyl Phosphate as a Primordial Energy Currency at the Origin of Life. Orig. Life. Evol. Biosph. (2018). 48: 159–179.

[6] Pinna, S., Kunz, C., Harrison, S.A.,  Jordan, S.F., Ward, J., Werner, F., Lane, N. A prebiotic basis for ATP as the universal energy currency. bioRxiv. (2021).

How to cite: Pinna, S., Werner, E., and Moran, J.: Metabolites and metals as phosphate transfer catalysts, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-70, https://doi.org/10.5194/epsc2022-70, 2022.

Coffee break
Chairpersons: Felipe Gómez, Nuria Rodríguez-González, Rosanna del Gaudio
15:30–15:45
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EPSC2022-140
Sohan Jheeta

The amino acid condensation reaction on a heterogeneous mineral surface has been regarded as one of the important pathways for peptide bond formation. Keeping this in view, we have studied the oligomerization of the simple amino acids, glycine and alanine, on nickel ferrite (NiFe2O4), cobalt ferrite (CoFe2O4), copper ferrite (CuFe2O4), zinc ferrite (ZnFe2O4), and manganese ferrite (MnFe2O4) nanoparticles surfaces, in the temperature range from 50–120  oC for 1–35 days, without applying any wetting/drying cycles. Among the metal ferrites tested for their catalytic activity, NiFe2O4 produced the highest yield of products by oligomerizing glycine to the trimer level and alanine to the dimer level, whereas MnFe2O4 was the least efficient catalyst, producing the lowest yield of products, as well as shorter oligomers of amino acids under the same set of experimental conditions. It produced primarily diketopiperazine (Ala) with a trace amount of alanine dimer from alanine condensation, while glycine was oligomerized to the dimer level. The trend in product formation is in accordance with the surface area of the minerals used. A temperature as low as 50 oC can even favour peptide bond formation in the present study, which is important in the sense that the condensation process is highly feasible without any sort of localized heat that may originate from volcanoes or hydrothermal vents. However, at a high temperature of 120 oC, anhydrides of glycine and alanine formation are favoured, while the optimum temperature for the highest yield of product formation was found to be 90 oC.

How to cite: Jheeta, S.: Thermal Condensation of Glycine and Alanine on Metal Ferrite Surface: Primitive Peptide Bond Formation Scenario, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-140, https://doi.org/10.5194/epsc2022-140, 2022.

15:45–16:00
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EPSC2022-352
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ECP
Rita Severino, Moisés Maestro-Lópes, Jorge Cuéllar, José María Valpuesta, and Victor Parro

Astrobiology is the study of the origin, evolution, and distribution of life in the context of cosmic evolution, which includes habitability in the Solar System and beyond (Horneck et al., 2016). After NASA was established in 1958, the agency began an effort to learn how to look for the presence of life beyond Earth - both ancient and current. This began with the Viking landers in 1976, but it was not until the 2012 landing of Curiosity that another astrobiology (though not life detection) mission began. Today there is a growing multidisciplinary community that aims at answering the question: Is there life beyond Earth and, if so, how can we detect it? Mars, in particular, once had water, atmosphere, and volcanic activity, where life could have flourished. There is also a slim chance that microbial life exists on Mars today. But how can we detect Martian life? Our research focuses on biosignatures as facilitating life detection (Horneck et al., 2016; Neveu, Hays, Voytek, New, & Schulte, 2018). Particularly, the identification and detection of functional molecules (DNA, lipids, proteins), using antibodies and immunoassays, in natural samples. Antibodies targeting proteins obtained from crude environmental extracts, from extreme environments on Earth, have been used as antigens in our research, successfully (Fernández-Martínez et al., 2019; Sanchez-Garcia et al., 2019). Recently, we tested ancestral proteins, obtained through Ancestral Sequence Reconstruction techniques, as antigens, and tested several terrestrial environments (Severino et al., in preparation). Results were promising, as their presence could be traced back to terrestrial paleoenvironments (environments that retain ancestral characteristics), thus opening a new field in astrobiology. Molecular chaperones are one of the oldest protein families, and Hsp60 (chaperonins) is the oldest clan, whose origins can be traced back to the last common ancestor (Rebeaud, Mallik, Goloubinoff, & Tawfik, 2021). They are commonly identified in extreme environments, either by metaproteomics, or microarray immunoassays (Fernández-Martínez et al., 2019; Sanchez-García et al., 2019). Here, we report the ancestral sequence reconstruction and protein resurrection of this family of proteins (Figure 1) and discuss our findings in the light of biogeochemistry, systems-level paleoenvironments characterization, and astrobiological applications (Kaçar, Guy, Smith, & Baross, 2017).

Figure 1. Bayesian phylogenetic reconstruction of the Hsp60 family of genes (on the left). TEM micrograph of the resurrected last common ancestor of Group I Hsp60 family of genes, clear frontal views highlighted by red circles (on the right).

Funding: Spain AEI project RTI2018-094368-B-I00 (VP) and PID2019-105872GBI00/AEI/10.13039/501100011033 (AEI/FEDER, UE) (JMV).

References: Horneck et al. (2016) Astrobiology, 16(3), 201–243. Fernández-Martínez, et al. (2019) Frontiers in Microbiology, 10, 1641. Neveu et al. (2018) Astrobiology, 18(11), 1375–1402. Sanchez-García et al. (2019) Frontiers in Microbiology, 10(JAN), 3350. Rebeaud, Mallik, Goloubinoff, & Tawfik (2021) PNAS, 118(21). Kaçar, Guy, Smith, & Baross (2017) Philos. Trans. Royal Soc. A, 375(2109).

How to cite: Severino, R., Maestro-Lópes, M., Cuéllar, J., Valpuesta, J. M., and Parro, V.: Resurrecting ancestral chaperonins as proxies for biomarker discovery in astrobiology, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-352, https://doi.org/10.5194/epsc2022-352, 2022.

16:00–16:15
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EPSC2022-100
Eva Mateo-Marti, Santos Galvez-Martinez, Eduardo Cueto-Diaz, and Maria Paz Zorzano

The role of minerals surfaces in prebiotic chemistry and planetary exploration

  • Mateo-Marti*, S.Galvez-Martinez, E. Cueto-Diaz and M.P Zorzano.

Centro de Astrobiología. INTA-CSIC. Torrejón de Ardoz, 28850 Madrid, Spain.

* mateome@cab.inta-csic.es

 Mineral substrates are essential in prebiotic chemistry field and play a crucial role for the preservation of molecules on planetary exploration, thus the chemistry behind the interaction between organic molecules and mineral surfaces has been object of interest for astrobiology in the last years. Therefore, deeper understanding about the guidelines that govern molecular adsorption on surfaces and chemical species were most favorable for the development of prebiotic chemistry and catalysis on mineral surfaces at the origin of Life. To this end, we study and characterize the adsorption processes and chemical reactivity of molecules on mineral surfaces, using advanced surface characterization techniques. A second objective is to study the role of mineral surfaces in catalyzing the formation of prebiotic organic compounds, as a possible source of energy and catalysts in the early stages of the formation of complex organic molecules. These studies are carried out experimentally in vacuum system: spectroscopies and microscopies on surfaces (SMS) and in the simulation chamber for planetary atmospheres and surfaces (PASC), equipment located at CAB.

Our recent studies have shown that pyrite induce UV-photocatalytic abiotic nitrogen fixation [1], also, pyrite mineral have been studied for testing glycine amino acid surrounding conditions minerals can form diverse surface chemistry patterns, driving the interaction of adsorbed amino acids and small peptides on its surface [2]. Furthermore, we have investigated the suitability single layer of silica nanoparticles with an average size of 200 nm deposited on pristine gold surfaces as a tool for CO2 recognition at standard Mars low pressures [3] and identifications of spectroscopic fingerprints corresponding to relevant molecular/minerals in Mars environments. These studies contribute to the understanding of molecular chemical reactivity and the role that minerals may have played in prebiotic chemistry and planetary exploration.

 

Figure 1. Photo of PASC and relevant applications for prebiotic chemistry and planetary exploration.

 

1.-E. Mateo-Marti, S. Galvez-Martinez, C. Gil-Lozano, M.P. Zorzano. Scientific Reports (2019) 9, 15311

2.-S. Galvez-Martinez, E. Escamilla-Roa, M.P. Zorzano, E. Mateo-Marti. Appl. Surf. Sci. (2020) 530 147182

3.- E. J. Cueto-Díaz * et al.,. Nanomaterials, 11 (2021) 2893.

How to cite: Mateo-Marti, E., Galvez-Martinez, S., Cueto-Diaz, E., and Zorzano, M. P.: The role of minerals surfaces in prebiotic chemistry and planetary exploration, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-100, https://doi.org/10.5194/epsc2022-100, 2022.

16:15–16:30
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EPSC2022-437
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ECP
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João Dias, Pedro Machado, José Ribeiro, and Constança Freire

We used the Planetary Spectrum Generator (PSG) [1] a radiative transfer suite, with the goal of simulating spectra from observations of Venus, Mars and Jupiter, searching for minor chemical species.

For Venus, sulphur dioxide (SO2) absorption lines were detected and its abundance constrained, by comparing simulations with observations by the Texas Echelon Cross Echelle Spectrograph (TEXES) spectrograph, around 7.4 μm [2]. The mean abundance of SO2 was constrained to 120 ppb, using the Optimal Estimation Method [3] and a line-depth ratio method [2] independently, in agreement with 50-175 ppb obtained by Encrenaz et al [2].  Phosphine (PH3) was not detected in the comparison between simulation and TEXES Infrared (IR) observations [4], around 10.5 μm, due to the presence of a strong telluric water band in the spectra.

For Mars, both a positive and a negative detection of methane were reanalyzed using PSG simulations with the goal of constraining the methane abundance. The related spectra observations in the IR, around 3.3 μm, report, respectively, to the Mars Express (MEx) [5] and ExoMars [6] space-probes.

For Jupiter, the detection of ammonia, phosphine, deuterated methane and methane was studied, by comparing simulations with IR observations by the Infrared Space Observatory (ISO), around 7-12 μm. [7]. The next step is focused in the determination of the abundances of the previous species. Independent simulations will be performed using PSG and the NEMESIS state-of-the-art radiative transfer suite [8]

Funding: This research was funded by the Portuguese Fundacao Para a Ciencia e Tecnologia under project P-TUGA Ref. PTDC/FIS-AST/29942/2017 through national funds and by FEDER through COMPETE 2020 (Ref. POCI-01-0145 FEDER-007672).

Aknowledgments: We credit Thérèse Encrenaz, from LESIA, Observatoire de Paris, for all the support and fruitful discussion; Geronimo Villanueva, from NASA-Goddard Space Flight Center, for discussing issues regarding PSG; Marco Giuranna, PI of the PFS instrument of Mars Express (ESA), Alejandro Cardesín, from ESAC-ESA, Ann Carine Vandaele, PI of the NOMAD instrument of ExoMars (ESA) and Séverine Robert, from the ExoMars team, for all the support regarding Mars dedicated research; Gabriella Gilli (IAA), for the collaboration regarding the LMD-VGCM model; Patrick Irwin, from the University of Oxford (UK), for the collaboration under the NEMESIS radiative transfer code; Asier Munguira, from the University of the Basque Country, for his availability to discuss atmospheric research methods in the context of the present work.

References

[1] Villanueva et al. 2018, Journal of Quantitative Spectroscopy and Radiative Transfer

[2] Encrenaz et al. 2012; Astronomy & Astrophysics

[3] C. D. Rodgers. Inverse methods for atmospheric sounding: theory and practice. World Scientific, 2008

[4] Encrenaz et al. 2020; Astronomy & Astrophysics.

[5] Giuranna et al. 2019; Nature

[6] Korablev et al. 2019.; Nature

[7] Encrenaz et al. 1999 ; Planetary and Space Science

[8] Irwin et al. 2008 ; Journal Of Quantitative Spectroscopy And Radiative Transfer

How to cite: Dias, J., Machado, P., Ribeiro, J., and Freire, C.: Atmospheric evolution and the search for species of astrobiological interest in the Solar System – Case Studies using the Planetary Spectrum Generator, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-437, https://doi.org/10.5194/epsc2022-437, 2022.

16:30–16:45
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EPSC2022-1108
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ECP
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Annemiek C. Waajen, Wessel de Wit, John O. Edgar, Jon Telling, and Charles S. Cockell

Intro

Kerogen is insoluble, macromolecular organic matter in sedimentary rocks. Kerogen is highly abundant on Earth, making this subsurface carbon reservoir larger than any single surface carbon reservoir. Based on the origin of the organic matter, four types of kerogens are distinguished, with each their own chemical composition (Fig. 1). Type 1 is derived from fresh water algae, type 2 from marine algae, type 3 from terrestrial vascular plants, and type 4 is partially decomposed organic matter. Next to the abundance of kerogens on Earth, kerogens also comprise 70% of the organic material in carbonaceous chondrites (Sephton, 2002), and similar macromolecular organics have been discovered on the surface of Mars (Eigenbrode et al., 2018). As kerogens consist of large, insoluble, non-hydrolysable complexes (>1kDa), they are difficult for many microorganisms to access as an energy or carbon source (Vandenbroucke, 2003; Petsch et al., 2001). On the contrary, macromolecular organic material had been shown to be inhibitory to biofilms through occlusion of the biofilm surface (Freeman and Lock, 1992).

 

There is little understanding in the interaction of microorganisms with macromolecular, kerogenous material. This understanding is important as kerogenous material is a large carbon reservoir on Earth, and microbial degradation could impact the global carbon cycle with influences for climate change. Further, as kerogenous material is highly abundant in carbonaceous chondrites, and macromolecular material has been found on the surface of Mars, potential microbial usage of this material could have astrobiological implications. A proxy for extraterrestrial macromolecular, kerogenous material is kerogen embedded in rocks on Earth. In this research, we investigated the influence of each of the four kerogen types in rocks on the growth of an anaerobic microbial community.

 

Methods

An anaerobic microbial community capable of growth with a carbonaceous chondrite as the sole carbon and energy source as described in Waajen et al. (2022) was used. This community was grown for 11 days in microcosms containing liquid M9 medium with acetate and powdered rocks. Four types of rocks were tested, either shale or coal, with each rock sample containing one of the four kerogen types. At the end of the growth period, the community composition was determined by 16S amplicon sequencing. We also investigated the production of CO2, CH4 and H2 in the microcosms.

 

Results and discussion

Kerogen type 1 and 2 enhanced microbial growth to some extent. The microbial community composition did not change in the presence of kerogen type 1, but did change significantly during growth on kerogen type 2. This indicates that the growth of only a subset of the microbial community was enhanced by the presence of kerogen type 2, while another part of the community was not. We are currently investigating the metabolisms present in these environments, which could give an indication as to which compounds in these rocks will have influenced the growth of the community.

 

Kerogen type 3 did not enhance microbial growth, which could be explained by the abundancy of phenols in this type of kerogen. Phenols can be inhibiting in higher concentrations (Van Schie and Young, 1998).

 

Since this community has already been shown to grow on carbonaceous chondrite, growth enhancement on kerogen type 4 was to be expected, since this type is the closest analogue to macromolecular organics in meteorites (Matthewman et al., 2013). However, the community changed significantly during the growth in the presence of kerogen type 4, indicating that there are still significant differences between these environments. Further, kerogen type 4 is considered the most inert type of kerogen, containing mainly consisting polycyclic aromatic hydrocarbons (PAHs). Small PAHs can be degraded by microorganisms (Bamforth and Singleton, 2005), but it remains unknown whether the larger PAHs that are found in space can be used by microorganisms.

 

In addition to kerogens, shales and coal contain a small fraction of soluble organic material that could have been used by the microorganisms. Other compounds in shales and coals, such as metals, could also have influenced microbial growth. Further investigation in the type of material accessed by the microorganisms is needed to understand whether inert material from this type of kerogen can be microbially degraded.

 

No biological H2, CO2 or CH4 production was observed, which could be caused by the absence of certain metabolisms, or the direct consumption of these gases by other microorganisms. Alternatively, the low concentration of microorganisms in the microcosms could also have resulted in the lack of an observable production of these gases. We are currently analysing microbial community composition to indicate the presence of metabolisms which could produce these gases.

 

The potential of kerogenous material enhancing microbial growth has implications for the potential of life on Mars and in the presence of meteorites. The enhancement would indicate that the presence of macromolecular organic material in these environments would increase the habitability of these environments. Additionally, the potential degradation of kerogens has implications for carbon cycling on Earth, with the potential of the degradation of a large carbon reservoir. The entry of this stored carbon to the carbon cycle would have a large impact on climate change and should be further investigated.

Figure 1: Chemical characteristics of the four kerogen types indicating the thermal maturation and products that can be given off for human oil and gas use. The hydrogen index is the H/C ratio, the oxygen index is the O/C ratio. Taken from McCarthy et al., 2011.

References

References

Bamforth et al., Journal of Chemical Technology & Biotechnology (2005).

Eigenbrode et al., Science (2018).

Freeman et al., Applied and Environmental Microbiology (1992).

Matthewman et al., Astrobiology (2013).

McCarthy et al., Oilfield Review (2011).

Petsch et al., Science (2001).

Sephton, Natural product reports (2002).

Vandenbroucke, Oil & gas science and technology (2003).

Van Schie et al., Applied and environmental microbiology (1998).

Waajen et al., Astrobiology (2022).

 

How to cite: Waajen, A. C., de Wit, W., Edgar, J. O., Telling, J., and Cockell, C. S.: Different forms of kerogenous carbon shape the growth and composition of anaerobic microbial communities, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-1108, https://doi.org/10.5194/epsc2022-1108, 2022.

16:45–17:00
Coffee break
Chairpersons: Rosanna del Gaudio, Frank Trixler, Felipe Gómez
17:30–17:45
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EPSC2022-1019
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ECP
Rahul K Kushwaha, Richárd Rácz, Sándor T S Kovács, Péter Herczku, Béla Sulik, Zoltán Juhász, Sándor Biri, Duncan V Mifsud, Sergio Ioppolo, Zuzana Kanuchová, Thomas A Field, Perry Hailey, Robert McCullough, and Nigel J Mason

To-date, a large number of molecules has been detected in the interstellar medium (ISM) and on the planetary and lunar bodies within our solar system; ranging from diatomic to complex organic species including precursors and biomolecules. The physical conditions in these astrophysical environments, such as; temperature, density, UV radiation and energetic charged particles, determine the reaction paths followed and the emergent complexity of molecules formed in these environments. Many laboratory experiments have been performed utilizing light sources (synchrotron, UV lamp) and high energy ion accelerator facilities to study the chemistry taking place in the ISM and planetary bodies. However, only limited types of positive ion species have been used to irradiate astrochemical ices despite the presence of many distinct types of ions in the ISM or surrounding planetary bodies. Our plan is to overcome this limitation and understand the interaction of many types of singly and multiply charged ions having wide energy ranges with astrochemical ices.

Recently, we commissioned a special astrochemistry experimental setup developed at Queens University, Belfast and updated in Debrecen at electron cyclotron resonance ion source (ECRIS) at ATOMKI, Debrecen. The ECRIS is a second generation 14 GHz source, a stand-alone device that is used to provide versatile low-energy ion beams and plasmas. One of the specialties of this ECRIS is that it is able to produce not only positive but also single-charged negative ions and certain molecular beams, as well. This range of ions will be very useful to unravel the chemistry in interstellar space/planetary bodies induce by both negative and positive ions in these environments. This set-up is a unique facility in the field of astrochemistry as it can explore the chemistry occurring due to irradiation by both low and high energy ions.

The setup consists of a closed cycle helium cryostat attached to a sixteen-port ultrahigh vacuum chamber (~10-10 mbar). The cold finger of the cryostat is coupled to a sample holder, which can be cooled to 11 K and warmed up to 320 K using a cartridge heater attached to the cold finger. To deposit an ice on the cooled substrate the gas is leaked into the chamber using an all-metal leak valve with a well-defined flow rate, the deposition can be done both in background and direct mode. The deposited ice can be irradiated with different positive and negative ions produced by the ECRIS at (0.5-30)*q keV beam energy (q: ion charge). The chemical evolution of the ice is monitored in situ using an FTIR spectrometer (Bruker, Vertex 70v) and a residual gas analyzer directly attached to the chamber can monitor both sputtered products and desorbed species using Temperature Programmed Desorption (TPD).

During the conference, we will discuss the specific features, importance and range of applications of this new astrochemistry setup and will present some preliminary results.

 

The authors gratefully acknowledge funding from the Europlanet 2024 RI which has been funded by the European Union Horizon 2020 Research Innovation Programme under grant agreement No. 871149. Work of P.H., B.S. and Z.J. has also been supported by the Hungarian OTKA Grant No. K128621.

How to cite: Kushwaha, R. K., Rácz, R., Kovács, S. T. S., Herczku, P., Sulik, B., Juhász, Z., Biri, S., Mifsud, D. V., Ioppolo, S., Kanuchová, Z., Field, T. A., Hailey, P., McCullough, R., and Mason, N. J.: Astrochemistry Experimental Setup at Atomki-ECRIS: A Europlanet Facility, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-1019, https://doi.org/10.5194/epsc2022-1019, 2022.

17:45–18:00
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EPSC2022-1188
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ECP
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Michael Phillips, Kimberley Warren-Rhodes, Nancy Hinman, Jeffrey Moersch, Michael Hofmann, Michael McInenly, Alfonso Davila, and Nathalie Cabrol

Introduction

In environments where it is difficult for life to function, microbial organisms tend to inhabit pockets of locally favorable climatic conditions. Micro-climates conducive to the persistence of life in an otherwise inhospitable environment – “refugia” – are spatially restricted and can be < centimeters in extent [1], [2]. Refugia may have been (and perhaps still are) perennially prevalent on Mars where conditions were likely never globally favorable to life for sustained periods of time [3]. The tendency for refugia to be small means that it may be difficult to locate features that could have served (or perhaps still do serve) as refugia for microorganisms on Mars. The spatial distribution of refugia in extreme environments across larger geographic extents is often non-random and may depend on many factors, biotic and abiotic [4]–[6]. Understanding patterns that refugia follow across larger geographic contexts as well as particular geologic phenomena (e.g., volcanic vents, dikes, stress fields) that are commonly associated with refugia may provide a way to infer regions of astrobiological interest, even if the specific, small, habitable patches (refugia) are below the resolving power of orbital instruments [6]. Here, we explore a case study of two terrestrial habitats in salt-encrusted paleo-lake basins (salars) in the Atacama and Altiplano of Chile to assess their characteristics and what factors are common between them. The Neogene salars of the Atacama and Altiplano are perhaps the best analogs on Earth for the Noachian/Hesperian salt-encrusted paleo-lakes of Mars [4], [7]–[12].

Evaporite habitats at Salar Grande and Salar de Pajonales

Salar Grande hosts decimeter scale nodules made of halite that serve as refugia for endolithic microbes [9]. [1] proposed a model to describe the evolution of nodules in halite-encrusted salars at the edges of polygonal features. To briefly summarize their model, halite nodules initiate at polygon edges in a salar with active ground water. Growth continues after ground water activity ceases as winds drive a moisture gradient, along which brines travel, toward the apex of the relatively higher relief nodules where more halite is deposited (Fig 1). The action of brines in halite nodules generates porosity at multiple spatial scales (nanometers to millimeters), contributing positively to their habitability [1].

Fig. 1 Halite nodules at Salar Grande. A) Drone-view of nodules and nodule clusters. Humans for scale. B) Close up of halite nodule showing endolithic community. C) Halite nodule evolution from [1].

Like Salar Grande, Salar de Pajonales hosts endoliths in refugia habitats. In a gypsum-covered region of Salar de Pajonales, alabaster (a high-porosity polymorph of gypsum) is the most reliable indicator for the presence of life [4]. Alabaster refugia are most commonly found associated with decimeter- to meter-tall ridges and domes [6], [10]. The domes and ridges form via water-related processes: hydration/dehydration cycles, volume changes associated with mineral precipitation from brines, and/or efflorescence deliquescence [10]. The formation of alabaster is likely predicated on the action of the near-surface water that drives the formation of ridges and domes (Fig. 2), though microbial activity may play a role as well [4]. Therefore, at Salar de Pajonales water activity generates positive topographic salt constructs and physiochemical changes to gypsum (formation of high-porosity alabaster) that foster an environment favorable to life.

Fig. 2 Models of ridge and dome formation at SdP. A) Drone-perspective view of ridges at SdP. B) Model for ridge formation from [10] involving volume change at the phreatic-vadose zone interface. C) Image of domes at SdP in different stages of development. D) Possible model of gyspsum dome formation from [16].

Discussion

            Across two salt-encrusted environments, one in the Atacama and the other in the Altiplano, with distinct evaporite mineralogy (halite versus gypsum), the activity of water resulted in decimeter- to meter-tall topographic constructs with nanometer- to millimeter-scale porosity conducive to the persistence of endoliths. We hypothesize that decimeter- to meter-tall topographic constructs (as opposed to erosional remnants or boulders) may be general indicators for relatively enhanced habitability in salt-encrusted paleo-lake basins because they require water to form. Although refugia – such as the precise location of endoliths in halite nodules or alabaster in gypsum domes and ridges – may not be observable from orbit, decimeter- to meter-scale salt constructs may be possible to identify with HiRISE or future orbital imagers with higher resolving power [6]. Chloride basins should be the targets of high-resolution imaging campaigns and efforts should be made to distinguish salt constructs from erosional remnants, boulders, and other relative topographic highs with which they could be confused. Salt constructs may be one of the few features, other than (fossil) hydrothermal vents, that have a high potential to both host and preserve microbial organisms, and that are specific targets, possibly identifiable from orbit, to which a rover could be driven. These characteristics make them attractive targets for future missions to Mars.

 

Reference:

[1]       O. Artieda et al., 2015, doi: 10.1002/esp.3771.

[2]       L. Hays, “NASA Astrobiology Strategy.” 2015.

[3]       R. Wordsworth et al., 2021, doi: 10.1038/s41561-021-00701-8.

[4]       K. Warren-Rhodes et al., Nature Astronomy. in review.

[5]       M. S. Phillips et al., Astrobiology, in review.

[6]       K. A. Warren-Rhodes et al., 2019. doi: 10.3389/fmicb.2019.00069.

[7]       M. M. Osterloo, et al., 2010, doi: 10.1029/2010JE003613.

[8]       T. D. Glotch, et al., 2016, doi: 10.1002/2015JE004921.

[9]       A. F. Davila et al., 2008, doi: 10.1029/2007JG000561.

[10]     N. W. Hinman et al., 2022, https://www.frontiersin.org/article/10.3389/fspas.2021.797591

[11]     N. A. Cabrol et al., 2007, doi: 10.1029/2006JG000298.

[12]     E. K. Leask and B. L. Ehlmann, 2022, doi: 10.1029/2021AV000534.

[13]     A. Szynkiewicz, et al., JGR, vol. 115, 2010.

How to cite: Phillips, M., Warren-Rhodes, K., Hinman, N., Moersch, J., Hofmann, M., McInenly, M., Davila, A., and Cabrol, N.: Salt constructs in paleo-lake basins as high-priority astrobiology targets., Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-1188, https://doi.org/10.5194/epsc2022-1188, 2022.

18:00–18:15
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EPSC2022-1267
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Thea Kozakis, João M. Mendonça, and Lars A. Buchhave

Molecular oxygen (O2) paired with a reducing gas is regarded as a promising biosignature pair for atmospheric characterization of terrestrial exoplanets.  In circumstances when O2 may not be detectable in a planetary atmosphere (for instance, at mid-IR wavelengths) it has been suggested that O3, the photochemical product of O2, could be used as a proxy to infer the presence of O2.  While O3 is not directly produced by life, it plays an important role in habitability as the ozone layer is the primary source of UV shielding for surface life on modern Earth.  However, O3 production is known to have a nonlinear dependence on O2, as well as being strongly influenced by the UV spectrum of the host star.  To evaluate the reliability of O3 as a proxy for O2 we used Atmos, a 1D coupled climate/photochemistry code, to study the O2-O3 relationship for "Earth-like'' habitable zone planets around a variety of stellar hosts (G0V-M5V) for O2 abundances from 0.01%-150% of the Present Atmospheric Level (PAL) on modern Earth.  We  studied how O3 emission features for these planetary atmospheres varied for different O2 and O3 abundances using the radiative transfer code PICASO.  Overall we found that the O2-O3 relationship differed significantly around different stellar hosts, with different trends for hotter stars (G0V-K2V) than cooler stars (K5V-M5V).  Planets orbiting hotter host stars experience an increase in O3 when O2 levels are initially decreased from the present atmospheric level, with maximum O3 abundance occurring at 25-55% PAL O2. Although this effect may seem counterintuitive, it is due to the pressure dependency on O3 production, as with less atmospheric O2 incoming UV photons capable of O2 photolysis are able to reach lower (denser) regions of the atmosphere to spark O3 formation.  This effect is not present for planets orbiting our cooler host stars (K5V-M5V), as the weaker incident UV flux (especially FUV flux) does not allow O3 formation to occur at dense enough regions of the atmosphere such that the faster O3 production outweighs a smaller source of O2 from which to create O3.  As a result, for cooler host stars the O3 abundance decreases as O2 decreases, albeit nonlinearly.  Interpretation of O3 emission spectral features was found to require knowledge of the atmosphere’s temperature profiles -particularly the temperature differences between the planetary surface and stratospheric temperature- which are highly influenced by the amount of stratospheric O3. Planets experiencing higher amounts of incident UV have more efficient O3 production and UV absorption leading to larger stratospheric temperature inversions, and therefore shallower emission features.  Overall it will be extremely difficult (or impossible) to infer precise O2 levels from an O3 measurement, however, with information about the UV spectrum of the host star and context clues, O3 will provide valuable information about potential surface habitability of an exoplanet.

How to cite: Kozakis, T., Mendonça, J. M., and Buchhave, L. A.: Is ozone a reliable proxy for molecular oxygen?, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-1267, https://doi.org/10.5194/epsc2022-1267, 2022.

18:15–18:30
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EPSC2022-794
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ECP
Valentin Moulay, Caroline Freissinet, Arnaud Buch, Felipe Gomez Gomez, and Cyril Szopa

Introduction: Europa and Enceladus, two ocean worlds in our solar system, are targets of high interest for astrobiology in the decades to come. Past space missions (Cassini-Huygens and Galileo) and recent observations with the Hubble Space telescope have revealed the presence of salts (sulfate and/or chloride) in the plumes of Enceladus and in the components of Europa’s surface (1-4). These salts could interfere in the in-situ chemical analyses of organic molecules present in the collected samples, thus limiting the chance to detect potential biosignatures in these worlds. In order to study this potential analytical interference, terrestrial analog samples to the ocean of Europa and Enceladus were characterized with gas chromatography mass spectrometry (GC-MS) and the associated pretreatment techniques (pyrolysis, derivatization and thermochemolysis) currently used for in-situ analyses of extraterrestrial environments.

             

Analog samples: Tirez lacustrine system is located in La Mancha, Spain. The samples studied in this work were collected from seven salty lakes in 2019. They are in liquid state and characterized by a high concentration of Mg, Na, SO4 and Cl. These samples are of particular interest for oceans worlds because of spectra obtained from Fourier transform infrared technique were similar to the Galileo spectral data for Europa (5). In addition, micro-organisms from the three domains (bacteria, archaea, eukaryotes) were identified in Tirez lake materials (6).

Among the numerous samples collected during the field trip, this work focused on ten of them for time of investigations.

 

Results: Thanks to the pretreatment techniques associated to GC-MS, numerous molecules were identified. For instance, with derivatization (dimethylformamide dimethyl acetal) all the components from triglycerides were detected such as fatty acids (Figure) and glycerol. For some sample among the ten selected, phytol coming from the degradation of chlorophyll present in cyanobacteria was also detected. In addition, pyrolysis at different temperatures revealed the presence of furan derivatives, as well as phenol derivatives and naphthalene ones. For the two first, these come from the thermal degradation of carbonates and peptides respectively. In spite of the presence of salts, these few results show that we can identify molecules coming from the living with the usual analytical techniques used for space exploration.

Figure: Chromatogram of a derivatized sample (from Lillo Lake) with DMF-DMA after evaporation of the water. I.S.: internal standard.

Perspectives: Numerous compounds from micro-organisms were not detected such as amino acids or nitrogenous bases. In the near future, we want to try to desalinate these samples in order to identified more organic biosignatures. In addition, specific extraction will be made, particularly for amino acids, in order to characterize their content and confirm or deny that the salts prevent their detection.

 

References: (1) T. B. McCord, Hydrated salt minerals on Europa's surface from the Galileo near-infrared mapping spectrometer investigation. Journal of Geophysical Research 104,  (1999). (2) Waite, Cassini Ion and Neutral Mass Spectrometer Enceladus Plume composition and Structure. Science 311, (2006). (3) S. K. Trumbo, M. E. Brown, K. P. Hand, Sodium chloride on the surface of Europa. Science Advances 5, eaaw7123 (2019). (4) S. K. Trumbo, et al., A New UV Spectral Feature on Europa: Confirmation of NaCl in Leading-hemisphere Chaos Terrain. (2022). (5) O. Prieto-Ballesteros, Tírez Lake as a Terrestrial Analog of Europa. (2003). (6) L. Montoya et al., Microbial community composition of Tirez lagoon (Spain), a highly sulfated athalassohaline environment. Aquatic Biosystems 9, 19 (2013).

How to cite: Moulay, V., Freissinet, C., Buch, A., Gomez Gomez, F., and Szopa, C.: Future in-situ chemical analysis on Europa and Enceladus: impact of salts on the detection of organic compounds in samples from hypersaline Tirez lake (La Mancha, Spain) with GC-MS., Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-794, https://doi.org/10.5194/epsc2022-794, 2022.

Display time: Mon, 19 Sep 08:30–Wed, 21 Sep 11:00

Posters: Mon, 19 Sep, 18:45–20:15 | Poster area Level 1

Chairpersons: Rosanna del Gaudio, Felipe Gómez, Sohan Jheeta
L1.67
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EPSC2022-57
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Cyprien Verseux and Tiago Ramalho

To be sustainable, a settlement on Mars should be as independent of Earth as possible in terms of material resources. This independence may be reached with the help of biological systems: those could perform a wide range of functions with a low impact on the surroundings. However, biological systems would best rely on resources available on Mars – as recycling alone would mean that the amounts of available resources decrease over time – and most organisms cannot utilize raw Martian resources directly.

A solution has been proposed which lies in using diazotrophic, rock-weathering cyanobacteria. Their physiology is such that they could, it seems, be fed with materials available on site: water mined from the ground or atmosphere; carbon and nitrogen sourced from the atmosphere; and the local regolith, from which it has been argued that they could extract the other necessary nutrients. The cultured cyanobacteria could then produce various consumables directly, such as dioxygen and dietary supplements but also support the growth of secondary producers (plants or microorganisms) which could, in turn, generate a wide range of critical consumables.

Various proofs-of-concept have been reported in the literature and evidence accumulates that some cyanobacteria could, indeed, be fed from Martian resources and provide feedstock for other organisms of biotechnological interest. But whether a system works at all is not sufficient to decide whether it should be integrated into mission plans: its cost-efficiency must be determined and compared to potential alternatives.

Among the factors that will determine this cost-efficiency is the fitness of cyanobacteria under (i) hypobaria (low pressures), and as a result low partial pressures of dinitrogen; and (ii) a dependence on regolith for all nutrients not provided as gases, which would also lead to high concentrations of highly oxidizing compounds (chiefly, perchlorates) in the extracellular medium. Another key element is the design of specific cultivation hardware.

In this presentation, we will present the wet-lab and in-silico work performed at the ZARM’s Laboratory of Applied Space Microbiology to study those factors and thereby assess, and improve, the efficiency of cyanobacterium-based, biological ISRU on Mars.

How to cite: Verseux, C. and Ramalho, T.: On the cost-efficiency of cyanobacterium-based, biological ISRU on Mars, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-57, https://doi.org/10.5194/epsc2022-57, 2022.

L1.68
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EPSC2022-118
Isabel Herreros, Cristina Escudero, David Gómez-Ortiz, Nuria Rodríguez, Aitor Martínez, Alejandro Suárez-Gordo, David Fernández-Remolar, Felipe Gómez, and Ricardo Amils

1. Introduction

Río Tinto (Huelva, Spain) is one of the largest natural acid environments in the world and a mineralogical analog of Mars. The peculiarities presented by the system are due to the high concentration of ferric ion (Fe+3) contained in its waters, which is responsible not only for its characteristic red color, but also for maintaining a constant acidic pH (≈2.3) along the almost 100km length of the river [1]. Results obtained in the MARTE and IPBSL drilling projects suggested that the origin of the high concentration of Fe+3 is due to the metabolic activity of a subsurface "bioreactor" which is capable of dissolving pyrite, the main metal sulfide in the Iberian Pyrite Belt (IPB) [2].

In order to verify this hypothesis, we have developed a numerical model to analyze the hydrodynamic behavior of the groundwater inside one of the geologic faults of the system as well as the generation and transport of the Fe+3 in solution. As input parameters for the model, we have used the hydrogeological (topography, mineralogy, water table...), physicochemical (iron concentration, oxygen presence, porosity...) and microbiological (pyrite dissolution rate mediated by microorganisms) data obtained after years of study of the ecosystem of Río Tinto [2].

2. Methods

2.1. Biological model

To calculate the iron release mediated by microorganisms along the fault (marked in red in Figure 1A), three different scenarios were considered depending on their pyrite content and oxygen concentration: case 1) oxidizing layer; case 2) anaerobic zone of disseminated pyrite; and case 3) anaerobic zone of massive pyrite (see Figure 1B).

Figure 1: A) Satellite image of the Peña de Hierro area. The locations of the main faults (black solid lines), as well as those of the different acidic springs (yellow dots), are shown (image modified from [3]). B) Section of the fault studied. In blue, case 1. In grey, case 2. In red, case 3.

The contribution of iron to groundwater due to the biological action of subsurface microorganisms was measured by incubating natural surface and subsurface samples, the latter obtained during the IPBSL project, with water and monitoring iron release over time. Negative sterile controls were carried out in parallel.

2.2. Hydromechanical model

The numerical model used to simulate the generation and transport of Fe+3 in the groundwater of Río Tinto consists of two phases:

  • Modeling the flow movement inside the porous medium by solving the seepage equations [4].
  • Once the water velocity has been determined, the generation and transport of Fe+3 is modeled by solving the advection-diffusion equations with a source term.

3. Results

The equations considered for the hydromechanical model are solved numerically by using the Finite Element Method. To this end, a non-structured 2D mesh of 15473 linear triangular elements is used to model the sectional area of the selected geologic fault (marked in red in Figure 1A). After solving the seepage equations in the sectional area depicted in Figure 1B using the physical parameters shown in Table 1, the pressure field is determined and thus, the water velocity can be calculated.

Table 1: Input parameters for the model