What is astrobiology? Which fields does it comprise and what makes an astrobiologist? Ask five scientists and you may end up with six different definitions. This issue was raised at the first symposium of the European network of Astrobiology Graduates (AbGradE), held last year in Edinburgh, when discussing whether the attendees' fields of study were represented in the astrobiology community.

Microbiological activities can be detected in various extreme environments on Earth, which suggest that extraterrestrial environments, such as on Mars, could host life. There have been proposed a number of biomarkers to detect extant life mostly based on specific molecules. Because terrestrial organisms have catalytic proteins (enzymes), enzymatic activity may also be a good indicator to evaluate biological activities in extreme environments. Phosphatases are essential for all terrestrial organisms because phosphate esters are ubiquitously used in genetic molecules (DNA/RNA) and membranes. In this study, we evaluated microbial activity in soils of the Atacama Desert, Chile, by analysing several biomarkers, including phosphatase activity. Phosphatases extracted with Tris buffer were assayed fluorometrically using 4-methylumbelliferyl phosphate as a substrate. The horizontal distribution of phosphatase activity and other parameters in soils from the Atacama Desert showed that phosphatase activity was positively correlated with amino acid concentration and colony-forming units and negatively correlated with precipitation amount. We found consistent that biochemical indicators including phosphatase significantly decreased in the extreme hyper-arid zone where rainfall of <25 mm year−1. The results were compared with phosphatase activities detected in extreme environments, such as submarine hydrothermal systems and Antarctic soils, as well as soils from ordinary environments. Overall, our results suggested that phosphatase activity could be a good indicator for evaluating biological activities in extreme environments.

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.

&lt;p&gt;&lt;strong&gt;Introduction&lt;/strong&gt;: 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.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Audience &amp; topics engaged&lt;/strong&gt;: 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.&lt;/p&gt;&lt;p&gt;&lt;br&gt;&lt;strong&gt;Collaborations&lt;/strong&gt;: 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.&lt;/p&gt;&lt;p&gt;&lt;br&gt;&lt;strong&gt;Online presence&lt;/strong&gt;: In the spirit of the &amp;#8220;work from home&amp;#8221; 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.&lt;/p&gt;&lt;p&gt;&lt;br&gt;&lt;strong&gt;Scope&lt;/strong&gt;: 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.&lt;/p&gt;