No abstract

Cave environments on Earth have long provided shelter to a variety of organisms, from microbes to humans. Though their scales of interest differ vastly, these two examples have sought the same comfort from caves: a stable and sheltered environment, protected from the woes of the surface world. Since the discovery of lava caves on Mars (see Sauro et al., 2020 for a review), they have become of renewed interest as targets for human shelter in future missions, as well as areas of astrobiological interest, with the potential of harboring traces of extant or extinct extraterrestrial life.

Astrobiology Graduates in Europe (AbGradE, pronounced ab-grad-ee) is an association of early-career scientists working in fields relevant to astrobiological research. Conceptualized in 2013, it was initially designed as a mini-conference or workshop dedicated to early-career researchers, providing a friendly environment where early-career minds would be able to present their research without being intimidated by the possibility of facing a more traditional audience, composed mainly of senior scientists. Within the last couple of years, AbGradE became the first point of call for European, but also for an increasing number of non-European, early-career astrobiologists. This article aims to present how AbGradE has evolved over the years (in its structure and in its way of organizing events), how it has adapted with the COVID-19 pandemic, and what future developments are considered.

No abstract

Cave environments on Earth have long provided shelter to a variety of organisms, from microbes to humans. Though their scales of interest differ vastly, these two examples have sought the same comfort from caves: a stable and sheltered environment, protected from the woes of the surface world. Since the discovery of lava caves on Mars (see Sauro et al., 2020 for a review), they have become of renewed interest as targets for human shelter in future missions, as well as areas of astrobiological interest, with the potential of harboring traces of extant or extinct extraterrestrial life.

<p><strong>Introduction</strong>: Astrobiology Graduates in Europe (AbGradE, pronounced ab-grad-ee) is an association of early-career scientists working in fields relevant to astrobiological research. Conceptualized in 2013, it was initially designed as a mini-conference dedicated to early-career researchers (ECAs) in a more relaxed environment than that of traditional conferences. Our meetings act as a networking opportunity, as well as a practice round and steppingstone for ECAs entering the world of academic research.</p><p><strong>Audience & topics engaged</strong>: Our audience is mostly composed of graduate students and post-doctoral fellows, but not only: undergraduates, senior scientists, and researchers from different disciplines with a strong interest in astrobiology are also welcome to attend our meetings. The topics engaged at our events, both symposia and workshops, naturally include the obvious themes related to astrobiology, and go beyond them by delving into social sciences and humanities (e.g., an online Space law and governance meeting in 2021). Specific workshops were organized on more practical issues like science communication, space mission design, networking, and navigating post-graduate research. Other issues, like mental health in a research context, are also considered for future editions.</p><p><br><strong>Collaborations</strong>: AbGradE has been involved in astrobiology schools, such as the EANA International hydrothermal spring school. As the spiritual daughter organization of EANA, AbGradE maintains strong ties with it while developing on its own into an organization by ECAs, for ECAs, in a similar fashion to how AbGradCon operates. Over the years, AbGradE also teamed up with other organizations, like the European Astrobiology Campus (EAC), the European Astrobiology Institute (EAI), and the Europlanet Early Career (EPEC) Network.</p><p><br><strong>Online presence</strong>: In the spirit of the “work from home” attitude prevalent during the COVID-19 pandemic, AbGradE has attempted to provide more online resources. Apart from moving meetings online, we have built a website and sent out a quarterly newsletter to keep ECAs engaged, and to encourage a sense of community during the lockdown-ridden time of the pandemic.</p><p><br><strong>Scope</strong>: Within the last couple of years, AbGradE became the first point of call for European, but also for an increasing number of non-European ECAs, especially with the recent development of online resources. This presentation aims to present how AbGradE has evolved over the years (in its structure and in its way of organizing events), how it has adapted with the COVID-19 pandemic, and what future developments are considered.</p>

<p>Polycyclic aromatic hydrocarbons (PAHs) represent ~20% of cosmically available carbon [1, 2]. The further photochemical evolution of PAHs on planetary surfaces is of interest to early Earth origin-of-life studies and Mars origin-of-life speculations. Much of the literature has focused on small molecules contained in meteorites, such as amino acids and nucleic acid bases, and their potential as a carbon source for prebiotic chemistry on early Earth. However, 75% of extraterrestrial organic matter in meteorites is in aromatic form [3], and is more likely to survive the journey to a planetary surface, during which much of the small molecules can be destroyed. These stable carbon compounds could later be broken down into smaller, more biologically relevant molecules by photocatalysis on clay mineral surfaces in the ultraviolet radiation regime of early Earth and Mars.</p> <p>Here we experimentally test whether PAHs degrade when adsorbed to nontronite clay and exposed to ultraviolet radiation. Experiments were performed at the INAF Observatory of Arcetri and in the PALLAS chamber at Utrecht University and were monitored with <em>in-situ</em> diffuse reflectance infrared spectrometry (DRIFTS) measurements. PAHs and any degradation products were extracted post-irradiation and analyzed with nuclear magnetic resonance (NMR).</p> <p>[1] Allamandola, L. J., Tielens, A. G. G. M., & Barker, J. R. (1989). <em>The Astrophysical Journal Supplement Series</em>, <em>71</em>, 733-775.</p> <p>[2] Puget, J. L., & Léger, A. (1989). <em>Annual review of astronomy and astrophysics</em>, <em>27</em>(1), 161-198.</p> <p>[3] Sephton, M. A. (2002). <em>Natural product reports</em>, <em>19</em>(3), 292-311.</p>

<p>Lava tubes on Mars hold exciting potential for the preservation of biosignatures, which may survive on geological timescales in these isolated, stable environments. To support the development of future astrobiological mission concepts, we turn to terrestrial lava tubes, host to a variety of microbial communities and secondary minerals. Following a multidisciplinary sampling protocol, we retrieved biological, molecular, and mineralogical data from several lava tubes in Iceland. We report on blue-colored copper-rich secondary minerals and their associated bacterial communities using a multi-method approach, and an amalgam of 16S rRNA gene sequencing, Raman spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy data sets. We found numerous bacterial genera known for their high metal resistance and ability to survive in low-nutrient environments. Both are characteristics to be expected for any potential life in Martian lava tubes, and should be considered when checking for contaminants in Mars mission preparations. Associated with the microbial mats, we identified several types of copper-rich secondary minerals, indicating localized copper enrichments in the groundwater, possibly stemming from overlying ash deposits and nearby hyaloclastite formations. Molecular analysis revealed carotenoid signals preserved within the copper speleothems. If found in Martian lava tubes, blue copper-rich mineral precipitates would be deserving of astrobiological investigation, as they have potential to preserve biosignatures and harbor life.</p>