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https://www.readbyqxmd.com/read/28926282/bacterial-and-archaeal-lipids-recovered-from-subsurface-evaporites-of-dalangtan-playa-on-the-tibetan-plateau-and-their-astrobiological-implications
#1
Ziye Cheng, Long Xiao, Hongmei Wang, Huan Yang, Jingjing Li, Ting Huang, Yi Xu, Nina Ma
Qaidam Basin (Tibetan Plateau) is considered an applicable analogue to Mars with regard to sustained extreme aridity and abundant evaporites. To investigate the possibility of the preservation of microbial lipids under these Mars analog conditions, we conducted a mineralogical and organic geochemistry study on samples collected from two Quaternary sections in Dalangtan Playa, northwestern Qaidam Basin, which will enhance our understanding of the potential preservation of molecular biomarkers on Mars. Two sedimentary units were identified along two profiles: one salt unit characterized by a predominance of gypsum and halite, and one detrital unit with a decrease of gypsum and halite and enrichment in siliciclastic minerals...
September 19, 2017: Astrobiology
https://www.readbyqxmd.com/read/28920443/four-fallacies-and-an-oversight-searching-for-martian-life
#2
J D Rummel, C A Conley
While it is anticipated that future human missions to Mars will increase the amount of biological and organic contamination that might be distributed on that planet, robotic missions continue to grow in capability and complexity, requiring precautions to be taken now to protect Mars, and particularly areas of Mars that might be Special Regions. Such precautionary cleanliness requirements for spacecraft have evolved over the course of the space age, as we have learned more about planetary environments, and are the subject of regular deliberations and decisions sponsored by the Committee on Space Research (COSPAR)...
September 16, 2017: Astrobiology
https://www.readbyqxmd.com/read/28915088/abiotic-and-biotic-formation-of-amino-acids-in-the-enceladus-ocean
#3
Elliot L Steel, Alfonso Davila, Christopher P McKay
The active plume at Enceladus' south pole makes the indirect sampling of its global ocean possible. The partially resolved chemistry of the plume, which points to conditions that are seemingly compatible with life, has made orbital sampling missions a priority. We present a conceptual model of energy flux, hydrothermal H2 production, and both abiotic and biotic production of amino acids. Based on the energy flux observed at the south pole and the inferred internal hydrothermal activity, we estimate an H2 production of 0...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28915087/feasibility-of-detecting-bioorganic-compounds-in-enceladus-plumes-with-the-enceladus-organic-analyzer
#4
Richard A Mathies, Md Enayet Razu, Jungkyu Kim, Amanda M Stockton, Paul Turin, Anna Butterworth
Enceladus presents an excellent opportunity to detect organic molecules that are relevant for habitability as well as bioorganic molecules that provide evidence for extraterrestrial life because Enceladus' plume is composed of material from the subsurface ocean that has a high habitability potential and significant organic content. A primary challenge is to send instruments to Enceladus that can efficiently sample organic molecules in the plume and analyze for the most relevant molecules with the necessary detection limits...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28910143/the-lost-city-hydrothermal-field-a-spectroscopic-and-astrobiological-analogue-for-nili-fossae-mars
#5
Elena S Amador, Joshua L Bandfield, William J Brazelton, Deborah Kelley
Low-temperature serpentinization is a critical process with respect to Earth's habitability and the Solar System. Exothermic serpentinization reactions commonly produce hydrogen as a direct by-product and typically produce short-chained organic compounds indirectly. Here, we present the spectral and mineralogical variability in rocks from the serpentine-driven Lost City Hydrothermal Field on Earth and the olivine-rich region of Nili Fossae on Mars. Near- and thermal-infrared spectral measurements were made from a suite of Lost City rocks at wavelengths similar to those for instruments collecting measurements of the martian surface...
September 14, 2017: Astrobiology
https://www.readbyqxmd.com/read/28910135/imaging-of-vanadium-in-microfossils-a-new-potential-biosignature
#6
Craig P Marshall, Alison Olcott Marshall, Jade B Aitken, Barry Lai, Stefan Vogt, Pierre Breuer, Philippe Steemans, Peter A Lay
The inability to unambiguously distinguish the biogenicity of microfossil-like structures in the ancient rock record is a fundamental predicament facing Archean paleobiologists and astrobiologists. Therefore, novel methods for discriminating biological from nonbiological chemistries of microfossil-like structures are of the utmost importance in the search for evidence of early life on Earth. This, too, is important for the search for life on Mars by in situ analyses via rovers or sample return missions for future analysis here on Earth...
September 14, 2017: Astrobiology
https://www.readbyqxmd.com/read/28886031/can-the-tardigrade-hypsibius-dujardini-survive-in-the-absence-of-the-geomagnetic-field
#7
Weronika Erdmann, Bogdan Idzikowski, Wojciech Kowalski, Bogdan Szymański, Jakub Z Kosicki, Łukasz Kaczmarek
Earth's geomagnetic field has undergone critical changes in the past. Studies on the influence of the magnetic field on Earth's organisms are crucial for the understanding of evolution of life on Earth and astrobiological considerations. Numerous studies conducted both on plants and animals confirmed the significant influence of the geomagnetic field on the metabolism of living organisms. Water bears (Tardigrada), which are a mong the most resistant animals due to their cryptobiotic abilities, show significant resistance to a number of environmental stressors, but the influence of the geomagnetic field on their fitness has not been addressed before...
2017: PloS One
https://www.readbyqxmd.com/read/28885042/searching-for-life-on-mars-before-it-is-too-late
#8
Alberto G Fairén, Victor Parro, Dirk Schulze-Makuch, Lyle Whyte
Decades of robotic exploration have confirmed that in the distant past, Mars was warmer and wetter and its surface was habitable. However, none of the spacecraft missions to Mars have included among their scientific objectives the exploration of Special Regions, those places on the planet that could be inhabited by extant martian life or where terrestrial microorganisms might replicate. A major reason for this is because of Planetary Protection constraints, which are implemented to protect Mars from terrestrial biological contamination...
September 8, 2017: Astrobiology
https://www.readbyqxmd.com/read/28872900/enceladus-plume-structure-and-time-variability-comparison-of-cassini-observations
#9
Ben D Teolis, Mark E Perry, Candice J Hansen, J Hunter Waite, Carolyn C Porco, John R Spencer, Carly J A Howett
During three low-altitude (99, 66, 66 km) flybys through the Enceladus plume in 2010 and 2011, Cassini's ion neutral mass spectrometer (INMS) made its first high spatial resolution measurements of the plume's gas density and distribution, detecting in situ the individual gas jets within the broad plume. Since those flybys, more detailed Imaging Science Subsystem (ISS) imaging observations of the plume's icy component have been reported, which constrain the locations and orientations of the numerous gas/grain jets...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28872897/a-novel-strategy-to-seek-biosignatures-at-enceladus-and-europa
#10
Philip Judge
A laboratory experiment is suggested in which conditions similar to those in the plume ejecta from Enceladus and, perhaps, Europa are established. With the use of infrared spectroscopy and polarimetry, the experiment might identify possible biomarkers in differential measurements of water from the open ocean, hydrothermal vents, and abiotic water samples. Should the experiment succeed, large telescopes could be used to acquire sensitive infrared spectra of the plumes of Enceladus and Europa, as the satellites transit the bright planetary disks...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28861052/expose-r2-the-astrobiological-esa-mission-on-board-of-the-international-space-station
#11
Elke Rabbow, Petra Rettberg, Andre Parpart, Corinna Panitz, Wolfgang Schulte, Ferdinand Molter, Esther Jaramillo, René Demets, Peter Weiß, Rainer Willnecker
On July 23, 2014, the Progress cargo spacecraft 56P was launched from Baikonur to the International Space Station (ISS), carrying EXPOSE-R2, the third ESA (European Space Agency) EXPOSE facility, the second EXPOSE on the outside platform of the Russian Zvezda module, with four international astrobiological experiments into space. More than 600 biological samples of archaea, bacteria (as biofilms and in planktonic form), lichens, fungi, plant seeds, triops eggs, mosses and 150 samples of organic compounds were exposed to the harsh space environment and to parameters similar to those on the Mars surface...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28836818/experimentally-testing-hydrothermal-vent-origin-of-life-on-enceladus-and-other-icy-ocean-worlds
#12
Laura M Barge, Lauren M White
We review various laboratory strategies and methods that can be utilized to simulate prebiotic processes and origin of life in hydrothermal vent systems on icy/ocean worlds. Crucial steps that could be simulated in the laboratory include simulations of water-rock chemistry (e.g., serpentinization) to produce hydrothermal fluids, the types of mineral catalysts and energy gradients produced in vent interfaces where hydrothermal fluids interface with the surrounding seawater, and simulations of biologically relevant chemistry in flow-through gradient systems (i...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28820643/a-prototype-ice-melting-probe-for-collecting-biological-samples-from-cryogenic-ice-at-low-pressure
#13
Ashley Davis
In the Solar System, the surface of an icy moon is composed of irregular ice formations at cryogenic temperatures (<200 K), with an oxidized surface layer and a tenuous atmosphere at very low pressure (<10(-6) atm). A lander mission, whose aim is to collect and analyze biological samples from the surface ice, must contain a device that collects samples without refreezing liquid and without sublimation of ice. In addition, if the samples are biological in nature, then precautions must be taken to ensure the samples do not overheat or mix with the oxidized layer...
August 2017: Astrobiology
https://www.readbyqxmd.com/read/28820642/correction-to-astrobiology-2017-17-2-126-135
#14
(no author information available yet)
No abstract text is available yet for this article.
August 2017: Astrobiology
https://www.readbyqxmd.com/read/28816521/plume-activity-and-tidal-deformation-on-enceladus-influenced-by-faults-and-variable-ice-shell-thickness
#15
Marie Běhounková, Ondřej Souček, Jaroslav Hron, Ondřej Čadek
We investigated the effect of variations in ice shell thickness and of the tiger stripe fractures crossing Enceladus' south polar terrain on the moon's tidal deformation by performing finite element calculations in three-dimensional geometry. The combination of thinning in the polar region and the presence of faults has a synergistic effect that leads to an increase of both the displacement and stress in the south polar terrain by an order of magnitude compared to that of the traditional model with a uniform shell thickness and without faults...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28804477/glaciers-and-ice-sheets-as-analog-environments-of-potentially-habitable-icy-worlds
#16
REVIEW
Eva Garcia-Lopez, Cristina Cid
Icy worlds in the solar system and beyond have attracted a remarkable attention as possible habitats for life. The current consideration about whether life exists beyond Earth is based on our knowledge of life in terrestrial cold environments. On Earth, glaciers and ice sheets have been considered uninhabited for a long time as they seemed too hostile to harbor life. However, these environments are unique biomes dominated by microbial communities which maintain active biochemical routes. Thanks to techniques such as microscopy and more recently DNA sequencing methods, a great biodiversity of prokaryote and eukaryote microorganisms have been discovered...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28799795/could-it-be-snowing-microbes-on-enceladus-assessing-conditions-in-its-plume-and-implications-for-future-missions
#17
Carolyn C Porco, Luke Dones, Colin Mitchell
We analyzed Cassini Imaging Science Subsystem (ISS) images of the plume of Enceladus to derive particle number densities for the purpose of comparing our results with those obtained from other Cassini instrument investigations. Initial discrepancies in the results from different instruments, as large as factors of 10-20, can be reduced to ∼2 to 3 by accounting for the different times and geometries at which measurements were taken. We estimate the average daily ice production rate, between 2006 and 2010, to be 29 ± 7 kg/s, and a solid-to-vapor ratio, S/V > 0...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28782019/alma-detection-and-astrobiological-potential-of-vinyl-cyanide-on-titan
#18
Maureen Y Palmer, Martin A Cordiner, Conor A Nixon, Steven B Charnley, Nicholas A Teanby, Zbigniew Kisiel, Patrick G J Irwin, Michael J Mumma
Recent simulations have indicated that vinyl cyanide is the best candidate molecule for the formation of cell membranes/vesicle structures in Titan's hydrocarbon-rich lakes and seas. Although the existence of vinyl cyanide (C2H3CN) on Titan was previously inferred using Cassini mass spectrometry, a definitive detection has been lacking until now. We report the first spectroscopic detection of vinyl cyanide in Titan's atmosphere, obtained using archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), collected from February to May 2014...
July 2017: Science Advances
https://www.readbyqxmd.com/read/28771029/methane-seepage-on-mars-where-to-look-and-why
#19
Dorothy Z Oehler, Giuseppe Etiope
Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars...
August 3, 2017: Astrobiology
https://www.readbyqxmd.com/read/28765566/martian-slope-streaks-as-plausible-indicators-of-transient-water-activity
#20
Anshuman Bhardwaj, Lydia Sam, F Javier Martín-Torres, María-Paz Zorzano, Ricardo M Fonseca
Slope streaks have been frequently observed in the equatorial, low thermal inertia and dusty regions of Mars. The reason behind their formation remains unclear with proposed hypotheses for both dry and wet mechanisms. Here, we report an up-to-date distribution and morphometric investigation of Martian slope streaks. We find: (i) a remarkable coexistence of the slope streak distribution with the regions on Mars with high abundances of water-equivalent hydrogen, chlorine, and iron; (ii) favourable thermodynamic conditions for transient deliquescence and brine development in the slope streak regions; (iii) a significant concurrence of slope streak distribution with the regions of enhanced atmospheric water vapour concentration, thus suggestive of a present-day regolith-atmosphere water cycle; and (iv) terrain preferences and flow patterns supporting a wet mechanism for slope streaks...
August 1, 2017: Scientific Reports
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