@misc{deVeraAlawiBackhausetal.2019,
  author    = {de Vera, Jean-Pierre Paul and Alawi, Mashal and Backhaus, Theresa and Baque, Mickael and Billi, Daniela and Boettger, Ute and Berger, Thomas and Bohmeier, Maria and Cockell, Charles and Demets, Rene and de la Torre Noetzel, Rosa and Edwards, Howell and Elsaesser, Andreas and Fagliarone, Claudia and Fiedler, Annelie and Foing, Bernard and Foucher, Frederic and Fritz, J{\"o}rg and Hanke, Franziska and Herzog, Thomas and Horneck, Gerda and H{\"u}bers, Heinz-Wilhelm and Huwe, Bj{\"o}rn and Joshi, Jasmin Radha and Kozyrovska, Natalia and Kruchten, Martha and Lasch, Peter and Lee, Natuschka and Leuko, Stefan and Leya, Thomas and Lorek, Andreas and Martinez-Frias, Jesus and Meessen, Joachim and Moritz, Sophie and Moeller, Ralf and Olsson-Francis, Karen and Onofri, Silvano and Ott, Sieglinde and Pacelli, Claudia and Podolich, Olga and Rabbow, Elke and Reitz, G{\"u}nther and Rettberg, Petra and Reva, Oleg and Rothschild, Lynn and Garcia Sancho, Leo and Schulze-Makuch, Dirk and Selbmann, Laura and Serrano, Paloma and Szewzyk, Ulrich and Verseux, Cyprien and Wadsworth, Jennifer and Wagner, Dirk and Westall, Frances and Wolter, David and Zucconi, Laura},
  title     = {Limits of life and the habitability of Mars},
  series = {Astrobiology},
  volume    = {19},
  journal   = {Astrobiology},
  number    = {2},
  publisher = {Liebert},
  address   = {New Rochelle},
  issn      = {1531-1074},
  doi       = {10.1089/ast.2018.1897},
  pages     = {145 -- 157},
  year      = {2019},
  abstract  = {BIOMEX (BIOlogy and Mars EXperiment) is an ESA/Roscosmos space exposure experiment housed within the exposure facility EXPOSE-R2 outside the Zvezda module on the International Space Station (ISS). The design of the multiuser facility supports-among others-the BIOMEX investigations into the stability and level of degradation of space-exposed biosignatures such as pigments, secondary metabolites, and cell surfaces in contact with a terrestrial and Mars analog mineral environment. In parallel, analysis on the viability of the investigated organisms has provided relevant data for evaluation of the habitability of Mars, for the limits of life, and for the likelihood of an interplanetary transfer of life (theory of lithopanspermia). In this project, lichens, archaea, bacteria, cyanobacteria, snow/permafrost algae, meristematic black fungi, and bryophytes from alpine and polar habitats were embedded, grown, and cultured on a mixture of martian and lunar regolith analogs or other terrestrial minerals. The organisms and regolith analogs and terrestrial mineral mixtures were then exposed to space and to simulated Mars-like conditions by way of the EXPOSE-R2 facility. In this special issue, we present the first set of data obtained in reference to our investigation into the habitability of Mars and limits of life. This project was initiated and implemented by the BIOMEX group, an international and interdisciplinary consortium of 30 institutes in 12 countries on 3 continents. Preflight tests for sample selection, results from ground-based simulation experiments, and the space experiments themselves are presented and include a complete overview of the scientific processes required for this space experiment and postflight analysis. The presented BIOMEX concept could be scaled up to future exposure experiments on the Moon and will serve as a pretest in low Earth orbit.},
  language  = {en}
}
@article{SpijkermanWackerWeithoffetal.2012,
  author    = {Spijkerman, Elly and Wacker, Alexander and Weithoff, Guntram and Leya, Thomas},
  title     = {Elemental and fatty acid composition of snow algae in Arctic habitats},
  series = {Frontiers in microbiology},
  volume    = {3},
  journal   = {Frontiers in microbiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2012.00380},
  pages     = {15},
  year      = {2012},
  abstract  = {Red, orange or green snow is the macroscopic phenomenon comprising different eukaryotic algae. Little is known about the ecology and nutrient regimes in these algal communities. Therefore, eight snow algal communities from five intensively tinted snow fields in western Spitsbergen were analysed for nutrient concentrations and fatty acid (FA) composition. To evaluate the importance of a shift from green to red forms on the FA-variability of the field samples, four snow algal strains were grown under nitrogen replete and moderate light (+N+ML) or N-limited and high light (-N+HL) conditions. All eight field algal communities were dominated by red and orange cysts. Dissolved nutrient concentration of the snow revealed a broad range of NH4+ (<0.005-1.2 mg NI-1) and only low PO43- (< 18 mu g P I-1) levels. The external nutrient concentration did not reflect cellular nutrient ratios as C:N and C:P ratios of the communities were highest at locations containing relatively high concentrations of NH4- and PO43-. Molar N:P ratios ranged from 11 to 21 and did not suggest clear limitation of a single nutrient. On a per carbon basis, we found a 6-fold difference in total FA content between the eight snow algal communities, ranging from 50 to 300 mg FA g C-1. In multivariate analyses total FA content opposed the cellular N:C quota and a large part of the FA variability among field locations originated from the abundant FAs C181n-9, C18 2n-6, and C183n-3. Both field samples and snow algal strains grown under -N+HL conditions had high concentrations of C181n-9. FAs possibly accumulated due to the cessation of growth. Differences in color and nutritional composition between patches of snow algal communities within one snow field were not directly related to nutrient conditions. We propose that the highly patchy distribution of snow algae within and between snow fields may also result from differences in topographical and geological parameters such as slope, melting water rivulets, and rock formation.},
  language  = {en}
}