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  1. Electron Acceptors and Carbon Sources for a Thermoacidophilic Archaea


    The thin line of Earth's atmosphere and the setting sun are featured in this image photographed by the crew of the International Space Station while space shuttle Atlantis on the STS-129 mission was docked with the station. Source: NASA Image credit: None
    The thin line of Earth's atmosphere and the setting sun are featured in this image photographed by the crew of the International Space Station while space shuttle Atlantis on the STS-129 mission was docked with the station. Source: NASA

    Researchers have uncovered details about the versatile energy metabolism of the thermoacidophilic archaea, Acidianus strain DS80. This organism grows both autotrophically and heterotrophically with a range of electron acceptors. The new study examines the growth response of strain DS80 to varying electron acceptors (sulfur, ferric iron, or oxygen), and the amount of CO2 assimilated into biomass under each set of conditions. The study ties carbon sources used by DS80 to electron acceptor availability.

    Microbial metabolism is essential in global biogeochemical cycles that affect the habitability of Earth. Studying the activities of microorganisms and their role in the environment is useful for understanding our planet, and provides insight into more general principles of habitability that could be applicable to other worlds.

    The study, “Electron Acceptor Availability Alters Carbon and Energy Metabolism in a Thermoacidophile,” was published in the journal Environmental Microbiology. The work was supported by NASA Astrobiology through the Exobiology Program and NASA Astrobiology Institute.

    Source: [Astrobiology at NASA]

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  1. Yosemite Granite Tells New Story About Earth's Geologic History


    Quartz analysis image. Source: Michael Ackerson / <a href="https://carnegiescience.edu/news/yosemite-granite-%E2%80%9Ctells-different-story%E2%80%9D-story-about-earths-geologic-history" target="_blank">Carnegia Science</a> Image credit: None
    Quartz analysis image. Source: Michael Ackerson / Carnegia Science

    Granite is a record keeper of the history of continental movement, volcanic activity, and thermal properties of Earth’s upper crust, going back as far as 4.4 billion years ago.

    Michael Ackerson and his team have analyzed granite rock samples found in Yosemite National Park, and their study reveals evidence of mineral crystallization occurring at a much lower temperature than previously thought possible—around 100-200 degrees cooler than currently assumed. This discovery has the potential to change the larger picture in our understanding of the geology of Earth’s past, including crust and magma formation, and the link between volcanoes, ores deposits, and granite.

    The paper, “Low-temperature crystallization of granites and the implications for crustal magmatism,” is published in Nature.

    A full press release is available through Carnegie Science.

    Source: [Nature (via Carnegie Science)]

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  1. Supporting SHERLOC in the Detection of Kerogen as a Biosignature


    Left: SHERLOC will be mounted on the arm of the Mars 2020 rover. Right: Scan of a stromatolitic limestone Mars analog sample shows kerogen (dark bands) hosted by carbonate (white areas). Image sources: NASA / SETI Institute. Image credit: None
    Left: SHERLOC will be mounted on the arm of the Mars 2020 rover. Right: Scan of a stromatolitic limestone Mars analog sample shows kerogen (dark bands) hosted by carbonate (white areas). Image sources: NASA / SETI Institute.

    The upcoming Mars 2020 rover mission will hunt for signs of past microbial life and indications of habitable conditions on Mars. A device mounted on the rover’s arm will aid in the detection of kerogens, fossilized organic materials in sedimentary rocks: a UV-wavelength excitation instrument called SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals).

    To inform NASA’s planning strategies for SHERLOC, Svetlana Shkolyar, a 2014 recipient of the NASA Astrobiology Early Career Collaboration Award, and her research team with the NASA Astrobiology Institute team based at SETI analyzed the capabilities of co-located time-gated Raman and fluorescent spectroscopy in detecting and distinguishing kerogen when scanning Mars analogue samples.

    The team’s findings, published in Astrobiology reveal promising results and highlight the value of combining co-located Raman and fluorescence spectroscopies, similar to those obtainable by SHERLOC, to strengthen the confidence of kerogen detection as a potential biosignature in complex samples.

    Source: [Astrobiology (via SETI Institute)]

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  1. New Estimates of Earth's Ancient Climate and Ocean pH


    Artist concept of the early Earth. Source: NASA's Goddard Space Flight Center Conceptual Image Lab Image credit: None
    Artist concept of the early Earth. Source: NASA's Goddard Space Flight Center Conceptual Image Lab

    A recent study provides new constraints on the environmental conditions that were present on the ancient Earth. Previous approximations of early Earth’s climate and ocean pH vary dramatically, but the new study aims to provide more accurate estimates. This is important because these conditions could have profoundly influenced the origins and early evolution of life.

    In the study, researchers applied a self-consistent geological carbon cycle model to the last 4 billion years of Earth’s history. The results predict that the climate was temperate, and that the ocean pH was nearly neutral throughout the Precambrian (4.6 billion years ...

    Source: [Astrobiology at NASA]

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  1. How Microbes From Spacecrafts Survive Clean Rooms


    In the Payload Hazardous Servicing Facility, workers prepare to lift the Mars Exploration Rover-1 (MER-B) onto a spin table during preflight processing of the spacecraft. Researchers at Cal Poly offer the first biochemical evidence explaining the reason why contamination persist after use of the cleaning facility. Image source: NASA/JPL/KSC Image credit: None
    In the Payload Hazardous Servicing Facility, workers prepare to lift the Mars Exploration Rover-1 (MER-B) onto a spin table during preflight processing of the spacecraft. Researchers at Cal Poly offer the first biochemical evidence explaining the reason why contamination persist after use of the cleaning facility. Image source: NASA/JPL/KSC

    Dr. Rakesh Mogul, professor of biological chemistry at Cal Poly Pomona and a 2016 Minority Institute Research Support (MIRS) Program (now the Astrobiology Faculty Diversity Program) Fellow and his team have discovered a reason why, even after thorough cleaning, certain microbes from spacecrafts can still survive in the clean rooms at NASA.

    Excerpted from the press release from Cal Poly Pomona:
    The research team analyzed several Acinetobacter strains that were originally isolated from the Mars Odyssey and Phoenix spacecraft facilities. They found that under very nutrient-restricted conditions, most of the tested strains grew on and biodegraded the cleaning agents used ...

    Source: [Astrobiology]

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  1. Radical Factors in the Evolution of Animal Life



    Scientists develop a new molecular timeline for the production of reactive oxygen species in the evolution of life. Source: Y. J. Taverne et al. / Wiley Online Library

    Complex animal life appeared in the earth’s record soon after the second major rise in atmospheric oxygen roughly 800 million years ago. The evolution of enzymatic reduction of oxygen yielded a several-fold increase in energy production by life on Earth, enabling this progression to multicellular animal life. However, higher atmospheric oxygen concentrations would also have been expected to result in increased levels of reactive oxygen species (ROS) – derivatives of oxygen that are harmful to life and that, for humans, can accelerate aging and cardiovascular disease.

    Yannick Taverne and his team, with support from Alternative Earths, the NASA Astriobiology Institute Team based at UC Riverside, have developed a molecular timeline for the production of ROS in the evolution of life. The paper is published in BioEssays.

    Source: [BioEssays (via UC Riverside)]

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  1. Understanding Oxygen as an Exoplanet Biosignature


    Potential false positive mechanisms for O<sub>2</sub>. This cartoon summarizes the atmospheric mechanisms by which O<sub>2</sub> could form abiotically at high abundance in a planetary atmosphere (Meadows, 2017). Image credit: Ron Hasler
    Potential false positive mechanisms for O2. This cartoon summarizes the atmospheric mechanisms by which O2 could form abiotically at high abundance in a planetary atmosphere (Meadows, 2017).

    Researchers are studying how environmental context can help determine whether oxygen (O2) detected in extrasolar planetary observations is more likely to have a biological source. The team provide an in-depth, interdisciplinary example of O2 biosignature identification and observation, which serves as the prototype for the development of a general framework for biosignature assessment.

    The article, Exoplanet Biosignatures: Understanding Oxygen as a Biosignature in the Context of Its Environment, is an open access article in the journal Astrobiology. The work was supported by the NASA Astrobiology Program and in part by the NASA Astrobiology Institute’s Virtual Planetary Laboratory ...

    Source: [Astrobiology]

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  1. Recap of the 2018 Astrobiology Graduate Conference (AbGradCon)


    Group photo of the participants at the 2018 Astrobiology Graduate Conference that took place June 4-7, 2018 in Atlanta Georgia. Image credit: AbGradCon Image credit: None
    Group photo of the participants at the 2018 Astrobiology Graduate Conference that took place June 4-7, 2018 in Atlanta Georgia. Image credit: AbGradCon

    The 14th Astrobiology Graduate Conference (AbGradCon) was successfully held from June 4-7, 2018 at the Georgia Institute of Technology, in Atlanta, Georgia, with 96 participants presenting 72 posters and 23 oral presentations Oral presentations were streamed via SAGANLive and are available at http://saganet.org/page/saganlive.

    The graduate student and postdoctoral fellow attendees hailed from 49 institutions and 9 different countries (Brazil, Canada, Czech Republic, Germany, India, Japan, Mexico, United Kingdom, and United States). In addition to the scientific program, the attendees gathered for social activities each night and an educational field trip to the Georgia Aquarium the ...

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  1. Astrobiologist Rebecca Rapf Receives Inaugural Maggie C. Turnbull Early Career Award


    Rebecca Rapf awarded with the Maggie C. Turnbull Community Service Award at AbGradCon 2018. Image source: <a href="https://turnbullaward.org/" target="_blank">https://turnbullaward.org/</a>. Image credit: None
    Rebecca Rapf awarded with the Maggie C. Turnbull Community Service Award at AbGradCon 2018. Image source: https://turnbullaward.org/.

    Rebecca Rapf, a postdoctoral scholar in physical chemistry at the Lawrence Berkeley National Laboratory, is the first recipient honored with the newly created Maggie C. Turnbull Award for community service.

    Rapf was selected from a group of 10 early career astrobiologists nominated by their peers based on their outstanding dedication to education, outreach, community engagement and professional service to the early career community. The award commemorates Margaret “Maggie” C. Turnbull, a pioneer in exoplanet research and the search for life in the universe and founder of the Astrobiology Graduate Conference (AbGradCon), now in its 14th year of existence.

    Read the full press release at the Berkeley SETI Research Center website.

    Source: [Berkeley SETI Research Center / AbGradCon]

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  1. Searching for the Great Oxidation Event in North America


    Map showing the distribution of the Huronian Supergroup and other Paleoproterozoic successions in the Great Lakes area. The two studied drill cores (150–4, 156–1) are located ca. 10 km north of the city of Elliot Lake, Ontario, Canada. Modified from the work of Rasmussen et al. (2013). Image credit: None
    Map showing the distribution of the Huronian Supergroup and other Paleoproterozoic successions in the Great Lakes area. The two studied drill cores (150–4, 156–1) are located ca. 10 km north of the city of Elliot Lake, Ontario, Canada. Modified from the work of Rasmussen et al. (2013).

    Members of the NASA Astrobiology Institute University of Wisconsin Team have reported the first in situ analysis of all four S isotopes in metasediments of the Paleoproterozoic Huronian Supergroup and examined sulfur isotope evidence for the Great Oxidation Event (GOE). The early study of Papineau et al. (2007) argued for placement of the GOE within the lower Huronian. However, this interpretation is not supported by the improved precision, analysis of 36S, and new textural interpretations of this study. Values of Δ33S are uniformly from -0.07 to 0.38‰ in the lower Huronian. The most commonly analyzed ...

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  1. Astrobiology Activities at the Chickasaw Nation Aviation and Space Academy


    Team members Gustavo Cruz-Diaz and Christopher Materese pose with Chickasaw students at the Chickasaw Nation Aviation and Space Academy (CNASA). Image credit: None
    Team members Gustavo Cruz-Diaz and Christopher Materese pose with Chickasaw students at the Chickasaw Nation Aviation and Space Academy (CNASA).

    Team members Gustavo Cruz-Diaz and Christopher Materese of the NAINASA Ames Research Center Team, participated in the Chickasaw Nation Aeronautics and Space Academy (CNASA) held in Ada, Oklahoma on June 5, 2018. The Chickasaw Nation has been conducting this week-long camp for several years in order to encourage their Native American students to consider careers in the STEM (Science, Technology, Engineering and Mathematics) fields. Drs. Materese and Cruz-Diaz talked to 22 students (8th to 12th grade) about research at NASA and made presentations that included several hands-on science demonstrations. The activities were designed to teach the students about molecular ...

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  1. NASA Finds Ancient Organic Material, Mysterious Methane on Mars


    This low-angle self-portrait of NASA's Curiosity Mars rover shows the vehicle at the site from which it reached down to drill into a rock target called "Buckskin" on lower Mount Sharp. Credits: NASA/JPL-Caltech/MSSS Image credit: None
    This low-angle self-portrait of NASA's Curiosity Mars rover shows the vehicle at the site from which it reached down to drill into a rock target called "Buckskin" on lower Mount Sharp. Credits: NASA/JPL-Caltech/MSSS

    NASA’s Curiosity rover has found new evidence preserved in rocks on Mars that suggests the planet could have supported ancient life, as well as new evidence in the Martian atmosphere that relates to the search for current life on the Red Planet. While not necessarily evidence of life itself, these findings are a good sign for future missions exploring the planet’s surface and subsurface.

    The new findings – “tough” organic molecules in three-billion-year-old sedimentary rocks near the surface, as well as seasonal variations in the levels of methane in the atmosphere – appear in the June 8 edition of the journal Science.

    The full press release is available through NASA.

    Related Stories:
    A feature story by Marc Kaufman, “Breakthrough Findings on Mars Organics and Mars Methane,” is available at Astrobiology at NASA.

    An interview with Roger Summons on finding organic matter on Mars is also available at MIT News.

    Source: [NASA]

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  1. Habitability of the Young Earth Could Boost the Chances of Life Elsewhere


    An artist’s concept of the early Earth. While still fairly inhospitable compared to today’s standards, the early Earth may have had a more moderate climate and ocean temperature and pH than had been thought. Image credit: NASA. Image credit: None
    An artist’s concept of the early Earth. While still fairly inhospitable compared to today’s standards, the early Earth may have had a more moderate climate and ocean temperature and pH than had been thought. Image credit: NASA.

    The conditions on the early Earth have long been a mystery, but researchers from NASA and the University of Washington have now devised a way to account for the uncertain variables of the time, in turn discovering that the conditions of early Earth may have been more moderate than previously thought.

    By applying these findings to other rocky planets, the researchers, whose results are published in the Proceedings of the National Academy of Sciences, conclude that the time-frame and likelihood of life persisting elsewhere is greater than first thought.

    Read the full story at Astrobiology Magazine.

    Source: [Astrobiology Magazine (astrobio.net)]

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  1. AbGradCon 2018 Live Webcast


    Image credit: None

    The Astrobiology Graduate Conference (AbGradCon) 2018, taking place June 4-8, will be webcast live via Livestream to SAGANet.org, the NASA Astrobiology Facebook page, and the NASA Astrobiology Institute Seminars and Workshops page.

    For more information, visit the AbGradCon website.

    Source: [AbGradCon]

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  1. Maggie C. Turnbull Astrobiology Early Career Service Award


    Image credit: None

    The Conveners of the 2018 Astrobiology Graduate Conference and the Berkeley SETI Research Center are proud to announce the creation of a new early career community service award in honor of Maggie C. Turnbull, the founder of the Astrobiology Graduate Conference.

    The call for Award Nominations are open through June 3rd, 2018.

    Source: [SAGANet.org]

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