DOCSLIB.ORG

Rachel L. Harris [email protected] | (+1) 336-883-5905 |

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Rachel L. Harris Rlh6@Princeton.Edu | (+1) 336-883-5905 | Updated April 2016 Rachel L. Harris [email protected] | (+1) 336-883-5905 | http://scholar.princeton.edu/rlh6 HOME ADDRESS MAILING ADDRESS 403 West Pine Street Princeton University Mount Airy, NC 27030 Guyot Hall, Room 113 Princeton, NJ 08544 EDUCATION Princeton University, Princeton, NJ USA September 2014 - Present Doctoral Student, Dept. of Geosciences Advisor: Dr. Tullis Onstott ([email protected]) Wellesley College, Wellesley, MA USA August 2010 - May 2014 B.A. Biological Sciences; Minor: Russian Institutional Honors: Sigma Xi GPA: 3.41/4.00 | Major GPA: 3.57/4.00 Senior Thesis: “Hydrodynamic conditions in marine benthic environments affect nutrient uptake and biomineralization in cyanobacterial mats” University of Edinburgh, Edinburgh, UK January 2013 – May 2013 Study Abroad Exchange Program GPA: 3.43/4.00 (converted to US scale) Russian State University for the Humanities (РГГУ), Moscow, Russia January 2012 Study Abroad Exchange Program GPA: 4.00/4.00 (converted to US scale) Mount Airy High School, Mount Airy, NC USA August 2006 – June 2010 High School Diploma - Valedictorian GPA: 4.00/4.00 PUBLICATIONS Lau, C. Y. M., Kieft, T., Kuloyo, O., Linage-Alvarez, B., vanHeerden, E., Lindsay, M., Magnabosco, C., Wang, W., Wiggins, J., Guol, L., Perlman, D., Kyin, S., Shwe, H., Harris, R., Oh, Y., Yi, M. J., Purtschert, R., Slater, G., Smart, S., Sigman, D., Ono, S., Wei, S., Li, L., Sherwood Lollar, B., Onstott, T. Two-tiered primary production in a deep subsurface sulphuretum. Submitted. Jahnke, L., Parenteau, M. N., Harris, R., Bristow, T., Farmer, J. D., and Des Marais, D. J. Lipid biomarker production and preservation in acidic ecosystems: relevance to early Earth and Mars. In Preparation. Updated April 2016 Jahnke, L., Parenteau, M. N., Harris, R. L., Carlson, M. M., Farmer, J. D., and Des Marais, D. J. Synthesis of 3-methylbacteriohopanepolyols by purple non-sulfur anoxygenic phototrophs. In Preparation. RESEARCH EXPERIENCE Aix-Marseille Université - Campus St. Jérôme, Marseille, France June 2014 – August 2014 Laboratoire Physique des Interactions Ioniques et Moléculaires (PIIM) Center National de la Recherche Scientifique (CNRS) Internship Advisor: Dr. Grégoire Danger ([email protected]) Optimization and quality control of the experimental set-up for Project VAHIIA (Volatile Analyses from the Heating of Interstellar/cometary Ice Analogues). Formation of cometary ice analogues using cryogenic and high vacuum technologies, as well as subsequent analysis of volatile organic compounds and organic residues coming from the heating of these analogues using GC-MS and Orbitrap high-resolution mass spectrometry. The goal of my research was to obtain information on potential chemical reactivity occurring inside cometary grains as a point of reference for data incoming from ESA’s Rosetta mission. Massachusetts Institute of Technology, Cambridge, MA USA January 2014 – May 2014 Department of Earth, Atmospheric, and Planetary Sciences MIT Undergraduate Research Opportunities Program/Wellesley College Senior Thesis Advisors: Dr. Tanja Bosak ([email protected]), Dr. Vanja Klepac-Ceraj ([email protected]) My thesis concerns cyanophycinase mediation in carbon and nitrogen cycling of benthic, marine, Subsection III cyanobacterial mats. I am currently investigating of cyanophycin expression in various regions of the mat as it relates to morphological and ecological observations using immunoassays. I take geochemical measurements of local N concentration, nitrate vs. ammonia, N-fixation, and also conduct high-resolution stable-isotope mapping of labeled bicarbonate 13 - (H CO3 ). I will use these data in conjunction with morphological observations and gene sequencing (16s rRNA, nifH, and CphA). I hypothesize that cyanophycin composition and function will vary according to species composition and nutrient availability, as such results have been implied for freshwater cyanobacteria from Yellowstone National Park, WY USA. NASA Ames Research Center, Moffett Field, CA USA June 2013 – August 2013 Exobiology Branch SSX Intern Advisor: Dr. David J. Des Marais ([email protected]) I continued to culture and characterize (via 16s rRNA sequencing) the same strain of anoxygenic purple non-sulfur bacteria species I had worked with in summer 2012. I also cultured several strains of Cyanidiales and Chlorella from Sulphur Works and Devil’s Kitchen localities. I developed a trial run of a volcanic rock dissolution experiment for the 2013-2014 Lassen Astrobiology Student Intern Program, which included mineral analysis of solid precipitates via XRD and comparison to alteration materials found in analogous hydrothermal sites in Lassen Volcanic National Park. I worked with the Geographic Information Systems software ArcGIS to develop a 3D hydrogeological map of California’s Southern Cascades. I participated in education and public outreach efforts at the 2013 Lassen Dark Sky Festival by giving field work Updated April 2016 demonstrations and public talks discussing the characteristics of Lassen that make it a Mars analogue site. NASA Ames Research Center, Moffett Field, CA USA June 2012 – August 2012 Exobiology Branch SETI Institute Research Experience for Undergraduates Advisor: Dr. David J. Des Marais ([email protected]) My research focused on early habitable environments and the evolution of complexity in support of the NASA Astrobiology Institute. Specifically, my work included conducting pure culture isolation and fatty-acid methyl ester (FAME) characterization of acid-tolerant purple non- sulfur bacteria from hydrothermal features in Lassen Volcanic National Park. I also participated in education and public outreach efforts by contributing to curriculum development of a NASA- sponsored astrobiology internship for high school junior and seniors – the Lassen Astrobiology Student Intern Program. Massachusetts Institute of Technology, Cambridge, MA USA May 2011 – August 2011 Department of Earth, Atmospheric, and Planetary Sciences MIT Undergraduate Research Opportunities Program Advisor: Dr. Tanja Bosak ([email protected]) In the Bosak Lab, I examined the microstructure of microbial mats produced by cyanobacteria under laboratory-controlled conditions, and compared these structures with those of fossils belonging to their 1-3 billion year-old (Ga) stromatolite ancestors. This process was developed to gain an understanding of the environmental conditions that existed in intertidal zones during the Precambrian, as well as the chronology of conditions that allowed for the rise of atmospheric oxygen – and consequently complex aerobic life – on Earth. In addition to hands-on research, I conducted literary research through my translation of primary scientific literature on the same subject from Soviet-era Russia. From this literary search, I began the process of reconstructing the stromatolite classification system using a dichotomous key approach to classify fossil stromatolite forms based on quantitative, morphological characteristics ranging from most general (macroscopic measurements), down to most subtle (i.e. microstructure) features. TEACHING EXPERIENCE Wellesley College, Wellesley, MA USA September 2012 – May 2014 Department of Astronomy Teaching Assistant Supervisor: Dr. Stephen Slivan ([email protected]) ASTR 102 – Introductory Astronomy Laboratory I served as an assistant laboratory instructor for introductory astronomy courses at Wellesley College. My training included knowledge of optics for both refracting and reflecting telescopes, which were used in my instruction for this course. I am also a licensed operator of two Victorian- era refraction telescopes (12” and 6” diameter lenses) and their respective domes for course- required student observing. Identification of major constellations of northern hemisphere. Updated April 2016 PUBLIC COMMUNICATIONS International Symposium of Microbial Ecology | Montréal, Canada 2016 Oral Presentation: “Elucidation of active players in biogeochemical cycling via fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB)” Biosignature Preservation Conference | Lake Tahoe, NV 2016 Poster: “Biomarker preservation potential of subsurface ecosystems” International Continental Drilling Program DSeis Workshop| Potchefstroom, South Africa 2015 Oral Presentation: “Technical considerations for deep-life drilling” Ruhlman Conference | Wellesley College 2014 Poster: “Hydrodynamic conditions in marine benthic environments affect nutrient uptake and biomineralization in cyanobacterial mats” Poster: “The Secret Ingredient in Cheese: Characterizing the Microbiome of Everyone’s Favorite Spoiled Dairy Product” American Geophysical Union Fall Meeting | San Francisco, CA 2013 Poster: “Lipid Biomarker Production and Preservation in Acidic Ecosystems: Relevance to Early Earth and Mars” “Big Picture Science” | Mountain View, CA 2012 Guest Speaker: “A Martian Curiosity”, 13 August 2012 Tanner Conference | Wellesley College 2012 Oral Presentation: “Following Curiosity: A Summer of Astrobiology Research for Mars Science Laboratory” Tanner Conference | Wellesley College 2011 Oral Presentation: “Catalysts of the Explosion: Stromatolites and their Role in the Ignition of Complex Life on Earth” Keck Northeast Astronomy Consortium Student Research Symposium | Wellesley College 2011 Oral Presentation: “Catalysts of the Explosion: Stromatolites and their Role in the Ignition of Complex Life on Earth” HONORS AND AWARDS National Science Foundation Graduate Research Fellow 2015-present Three Generations Prize for Writing in the Sciences – Wellesley College 2014 Edward M. Armfield Scholar -- Northwestern North Carolina 2010 – 2014 Frances Meaker Colville Scholar – Wellesley College 2013 – 2014 Office of the Provost Student Research Grant – Wellesley College 2013 Dr. Gerald A. Soffen Memorial Travel Grant 2013 SOCIETY MEMBERSHIP International Symposium of Microbial Ecology 2016 - present Sigma Xi 2014 - present .
Load more

Recommended publications
  • Foundations of Complex Life: Evolution, Preservation and Detection on Earth and Beyond
    National Aeronautics and Space Administration NASA Astrobiology Institute Annual Science Report 2016 Team Report: Foundations of Complex Life: Evolution, Preservation and Detection on Earth and Beyond, Massachusetts Institute of Technology Foundations of Complex Life Evolution, Preservation and Detection on Earth and Beyond Lead Institution: Massachusetts Institute of Technology Team Overview Foundations of Complex Life is a research project investigating the early evolution and preservation of complex life on Earth. We seek insight into the early evolution and preservation of complex life by refining our ability to identify evidence of environmental and biological change in the late Mesoproterozoic to Neoproterozoic eras. Better understanding how signatures of life and environment are preserved will guide how and where to look for evidence for life elsewhere in the universe—directly supporting the Curiosity mission on Mars and helping set strategic goals for future explorations of the Solar System and studies of the early Earth. Our Team pursues these questions under five themes: I. The earliest history of animals: We use methods from molecular biology, experimental taphonomy, and paleontology to explore what caused the early divergence of animals. Principal Investigator: II. Paleontology, sedimentology, and geochemistry: We track the origin of complex Roger Summons protists and animals from their biologically simple origins by documenting the stratigraphy, isotopic records, and microfossil assemblages of well-preserved rock successions from 1200 to 650 million years ago. III. A preservation-induced oxygen tipping point: We investigate how changes in the preservation of organic carbon may have driven the Neoproterozoic oxygenation of the oceans coincident with the appearance of complex life.
    [Show full text]
  • MARTIAN PALEOMAGNETISM with the SQUID MICROSCOPE Thesis
    MARTIAN PALEOMAGNETISM WITH THE SQUID MICROSCOPE Thesis by Benjamin Paul Weiss In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2003 (Defended January 28, 2003) ii 2003 Benjamin Paul Weiss All Rights Reserved iii ACKNOWLEDGEMENTS There are of course many people who need to be thanked for making this thesis possible, but by far the most important of these is Joe Kirschvink. Joe couldn’t have had me in his lab more than a week before trusting me and a fellow undergraduate—the two of us new to geology, unproven and truly nobodies—to stay up all night slicing up the martian meteorite ALH84001. All night long we kept laughing out of excitement and disbelief as we played with not only an invaluable rock from Mars but the oldest known rock from any planet! This ability to inspire through his trust is Joe’s genius as a teacher. Joe also taught me how to be at once fearlessly creative and within the bounds of rigor. To me, it is the stories—of the rocks, of the events of the past, and of how we learn about them—that were what attracted me to planetary science in the first place. Trucking around the world with Joe (through South Africa, Swaziland, Mexico, Australia, Japan…), I saw some really strange rocks and places, which had even stranger stories to tell. Strange, at least, when told through Joe as their interpreter (Joe says I am a Martian that has just recently taken over a human body but hasn’t quite learned how to use all of the equipment; if this is true, then where did he come from?).
    [Show full text]
  • Tanja Bosak Was Born in Croatia and Graduated from the Zagreb University with a Degree in Geophysics
    Tanja Bosak was born in Croatia and graduated from the Zagreb University with a degree in Geophysics. After a summer of research at JPL, she moved to the California Institute of Technology in Pasadena, where she studied signatures of microbial processes in ancient sedimentary rocks and earned a Ph.D. in Geobiology. She spent two years at Harvard as a Microbial Initiative Postdoctoral Fellow, joined the Department of Earth, Atmospheric and Planetary Sciences at MIT in 2007 and is now a Professor of Geobiology and the group leader of the Program in Geology, Geochemistry and Geobiology. Tanja’s work integrates microbiology, sedimentology and stable isotope geochemistry into experimental geobiology to ask how microbial processes leave chemical, mineral and morphological signals in sedimentary rocks. Her lab uses this approach to explore modern biogeochemical and sedimentological processes, interpret the co-evolution of life and the environment during the first 80% of Earth history and look for signs of past life on Mars. For this work, and her work with graduate students and undergraduates, Bosak received the Subaru Outstanding Woman in Science award by the Geological Society of America (2007), the Macelwane Medal from the American Geophysical Union (2011), the Edgerton Award for young faculty at MIT (2012), the Undergraduate Research Opportunities for Undergraduates Mentor of the Year award by MIT (2012) and the Award for Outstanding Contributions and Dedication to Geobiology and Geomicrobiology from The Geobiology and Geomicrobiology Division of The Geological Society of America. Bosak is a fellow of the American Geophysical Union (2011), the American Academy of Microbiology (2021), and a subject editor for Geobiology, Frontiers of Microbiology and Geochemical Perspectives Letters.
    [Show full text]
  • Microbial Facies in a Sturtian Cap Carbonate, the Rasthof Formation, Otavi Group, Northern Namibia
    Precambrian Research 181 (2010) 187–198 Contents lists available at ScienceDirect Precambrian Research journal homepage: www.elsevier.com/locate/precamres Microbial facies in a Sturtian cap carbonate, the Rasthof Formation, Otavi Group, northern Namibia Sara B. Pruss a,∗, Tanja Bosak b, Francis A. Macdonald c, Marie McLane a, Paul F. Hoffman c,d a Department of Geosciences, Smith College, Northampton, MA 01063, USA b Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA c Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA d School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada V8W 2Y2 article info abstract Article history: Microbial structures in Neoproterozoic cap carbonates record the environmental processes present in Received 4 February 2010 the aftermath of global glaciation. The Rasthof Formation of northern Namibia is a unique carbonate Received in revised form 24 May 2010 depositional sequence that formed during post-glacial transgression and highstand following the Chuos Accepted 2 June 2010 glaciation. Carbon isotope profiles from four examined localities reveal that onlap was diachronous over post-glacial, syn-rift topography. The lower Rasthof Formation consists primarily of dark gray thinly (<mm) and thickly (1–4 mm) laminated microbialites that exhibit different rheological responses to the Keywords: emplacement of syndepositional dikes. The thinly laminated microbialaminite facies commonly host cm- Cryogenian Roll-up structure sized syndepositional folds of microbially laminated sediment called roll-up structures. In more thickly Neoproterozoic laminated facies, layers are deformed into broad decimeter-sized folds, but roll-up structures are absent.
    [Show full text]
  • 1 Curriculum Vitae Colleen Michelle Hansel
    CURRICULUM VITAE COLLEEN MICHELLE HANSEL Biogeochemist Department of Marine Chemistry and Geochemistry Telephone: 508‐289‐3738 Woods Hole Oceanographic Institution E‐mail: [email protected] Woods Hole, MA 02543 www.whoi.edu/science/MCG/microgeochem EDUCATION 2004 Ph.D. in Biogeochemistry, Department of Geological and Environmental Sciences, Stanford University 1999 M.S. in Environmental Chemistry, Department of Plant, Soil, and Entomological Sciences, University of Idaho 1997 B.S. in Geology, Department of Geological Sciences, California State University, Sacramento PROFESSIONAL EXPERIENCE 2015‐present Associate Scientist with tenure, Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution 2012‐2015 Associate Scientist, Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution 2011‐2012 Associate Professor, School of Engineering and Applied Sciences and Department of Earth and Planetary Sciences, Harvard University 2009‐2011 Assistant Professor, Department of Earth and Planetary Sciences, Harvard University 2007‐2011 Assistant Professor, School of Engineering and Applied Sciences, Harvard University 2004‐2006 Postdoctoral Scholar, Department of Geological and Environmental Sciences, Stanford University 2000‐2004 Graduate Researcher, Department of Geological and Environmental Sciences, Stanford University HONORS AND AWARDS 2016 Guest investigator fellowship at the Helmholtz Center in Geesthacht, Germany (October 30- December 16, 2017) 2014 Mineralogical Society of America Distinguished
    [Show full text]
  • Department of Earth, Atmospheric, and Planetary Sciences
    DEPARTMENT OF EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES DEPARTMENT OF EARTH, ATMOSPHERIC, AND Michael J. Follows, PhD PLANETARY SCIENCES Professor of Oceanography Professor of Civil and Environmental Engineering Timothy L. Grove, PhD R R Shrock Professor of Earth and Planetary Sciences Faculty and Teaching Sta Professor of Geology Robert D. van der Hilst, PhD Bradford H. Hager, PhD Schlumberger Professor of Geosciences Cecil and Ida Green Professor in Earth Sciences Head, Department of Earth, Atmospheric, and Planetary Sciences Colette L. Heald, PhD J. Taylor Perron, PhD Germeshausen Professor of Civil and Environmental Engineering Professor of Geology Professor of Earth, Atmospheric and Planetary Sciences Associate Head, Department of Earth, Atmospheric, and Planetary Sciences Thomas A. Herring, PhD Professor of Geophysics David McGee, PhD Associate Professor of Paleoclimate Oliver E. Jagoutz, PhD Associate Head for Diversity, Equity, and Inclusion Professor of Geology Professors Rubén Juanes, PhD Richard P. Binzel, PhD Professor of Civil and Environmental Engineering Professor of Planetary Sciences John C. Marshall, PhD Professor of Aeronautics and Astronautics Professor of Oceanography Tanja Bosak, PhD (On sabbatical, spring) Professor of Geobiology Frank Dale Morgan, PhD (On sabbatical) Professor of Geophysics Edward A. Boyle, PhD Paul O'Gorman, PhD Professor of Ocean Geochemistry Professor of Atmospheric Science Laurent Demanet, PhD Shuhei Ono, PhD Professor of Mathematics Professor of Geochemistry Professor of Earth, Atmospheric and Planetary Sciences Ronald G. Prinn, PhD Kerry Andrew Emanuel, PhD TEPCO Professor Cecil and Ida Green Professor of Atmospheric Science Professor of Atmospheric Chemistry Dara Entekhabi, PhD Daniel H. Rothman, PhD Bacardi and Stockholm Water Foundation Professor Professor of Geophysics Professor of Civil and Environmental Engineering Professor of Earth, Atmospheric and Planetary Sciences Leigh H.
    [Show full text]
  • Earth. Planets. Climate. Life. Life
    Earth. Planets. Climate. Life. Life on Earth emerged over 3.5 billion years ago, but we still search for answers to the most basic questions about our origins. The Earth teems with life, but surprisingly little is understood about how life began and took hold. The science of the origins and evolution of life is extraordinarily complex, with biology and earth science inextricably intertwined. From studies of ancient rocks and modern day organisms we now know that tiny microbes—the earliest forms of life—have played an outsized role in shaping the environmental systems of our planet for billions of years. Some learned to harvest energy from sunlight and produce oxygen, which over time became a key atmospheric ingredient enabling more complex forms of life to evolve and thrive. Some contributed to the extinction of species by spewing atmosphere- warming methane in quantities large enough to alter the climate. While still others nourish plant life by fixing nitrogen from the air into the soil. EAPS scientists are driven to discover the inner workings of the natural world by asking fundamental questions. When did photosynthesis begin? How did life evolve and how does it continue to adapt to changes in the environment? Is Earth a stable system? How did its present state come to be? How might the impact of human or natural processes compromise its stability? What caused mass extinctions of the past? Could we be approaching another? Can we find biosignatures in the atmospheres of distant exoplanets? Or in the rocks of Mars? Ultimately, is life unique to Earth? Why study the origins and evolution of life? MIT-WHOI Joint Program student Hannah Barkley takes a core sample from Every major event in the history of life has been a coral skeleton to accompanied by environmental change.
    [Show full text]
  • The Meaning of Stromatolites
    EA41CH02-Bosak ARI 19 April 2013 9:0 The Meaning of Stromatolites Tanja Bosak,1 Andrew H. Knoll,2 and Alexander P. Petroff1 1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; email: [email protected] 2Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 Annu. Rev. Earth Planet. Sci. 2013. 41:21–44 Keywords First published online as a Review in Advance on biosignature, early life, reef, microbialite, evolution January 30, 2013 The Annual Review of Earth and Planetary Sciences is Abstract online at earth.annualreviews.org Stromatolites document microbial interactions with sediments and flowing This article’s doi: water throughout recorded Earth history and have the potential to illu- 10.1146/annurev-earth-042711-105327 minate the long-term history of life and environments. Modern stroma- c by Massachusetts Institute of Technology (MIT) on 08/22/14. For personal use only. Copyright 2013 by Annual Reviews. tolites, however, provide analogs to only a small subset of the structures Annu. Rev. Earth Planet. Sci. 2013.41:21-44. Downloaded from www.annualreviews.org All rights reserved preserved in Archean and Proterozoic carbonates. Thus, interpretations of secular trends in the shapes and textures of ancient columnar stromatolites require nonuniformitarian, scale-dependent models of microbial responses to nutrient availability, seawater chemistry, influx of sediment grains, shear, and burial. Models that integrate stromatolite scales, macroscopic organiza- tion, and shapes could also help test the biogenicity of the oldest stromato- lites and other structures whose petrographic fabrics do not preserve direct evidence of microbial activity. An improved understanding of stromatolite morphogenesis in the presence of oxygenic and anoxygenic microbial mats may illuminate the diversity of microbial metabolisms that contributed to stromatolite growth in early oceans.
    [Show full text]
  • Exploring the Silicification of Microbes and Understanding Their Role in the Fossil Record by Kyle J
    Exploring the silicification of microbes and understanding their role in the fossil record by Kyle J. Morgenstein Submitted to the Department of Earth, Atmospheric and Planetary Sciences in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science in Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology May 20, 2020 Copyright 2020 Kyle Morgenstein. All rights reserved. The author hereby grants to MIT permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part in any medium now known or hereafter created. Author_______________________________________________________________ Department of Earth, Atmospheric and Planetary Sciences May 20, 2020 Certified by______________________________________________________ Tanja Bosak Thesis Supervisor Accepted by______________________________________________________ Richard P. Binzel Chair, Committee on Undergraduate Program Abstract Filamentous cyanobacteria that built macroscopic tufted mats in Proterozoic peritidal environments were fossilized by silicification, but the environmental and biological factors that shaped these structures and enabled this type of preservation are not well understood. Recent work has shown that coccoidal cyanobacteria can become fossilized because they can sequester silica from seawater that is undersaturated with respect to silica. Here, we use taphonomy experiments to demonstrate that filamentous cyanobacteria that form tufted and conical mats are also able to mediate the precipitation of silica in seawater that is undersaturated with respect to silica as well. These results show that different marine cyanobacteria and their macroscopic structures have a high potential to be preserved by silicification. We find that the exterior of macroscopic structures such as tufts and pillars are preferentially silicified, and more completely silicifed at silica concentrations below saturation in seawater.
    [Show full text]
  • Why Does the Aurora Flare
    VOL. 96 NO. 8 1 MAY 2015 Earth & Space Science News WhyCover Hed Sub Does the Aurora Flare Up? Cannon Blasts Mimic Volcanic Eruptions White House Submits U.S. Emission Targets Volatiles in Mars Pedal for the Planet– and AGU Take part in a life-changing 5-day bike ride or hike adventure, while increasing awareness for sustainability, renewable energy, and environmental causes. Plus, the money you raise riding will go toward helping AGU further its mission and vision! • Ride through breathtaking scenery and challenge yourself physically • Hear from bright minds in policy, advocacy, and innovati on in a nightly speaker series • Connect with peers who are united to support sustainability and protect our planet • Support AGU by selecti ng us as your benefi ciary when you register Save 25% on Join the AGU Team! Registrati on fees. Ride with your fellow geoscienti sts on the Use promo code AGU team on the Northeast Ride from AGUSpecial Bar Harbor to Boston, 17-21 September. The team will be led by AGU President- elect Eric Davidson. climateride.agu.org Earth & Space Science News Contents 1 MAY 2015 PROJECT UPDATE VOLUME 96, ISSUE 8 Fire in the Hole: 12 Recreating Volcanic Eruptions with Cannon Blasts Artificial volcanic plumes, fired from cannons loaded with ash plucked from the slopes of Iceland, may help researchers better monitor disruptive eruptions. NEWS 6 White House Submits Greenhouse Gas Emission Targets Before the climate summit in Paris this November and December, the United States and some other countries have submitted their targets to cut emissions. RESEARCH SPOTLIGHT 16 26 COVER California’s 2012–2014 Drought Why Does the Aurora Flare Up? Unusual for Last Millennium Soil moisture estimates, inferred from The spectacular auroras that circle Earth’s geomagnetic poles and thousands of tree rings spanning the past burst with colorful displays during geomagnetic storms have mystified 12 centuries, highlight the severity of the humanity for millennia.
    [Show full text]
  • Overview and Kepler Update
    Overview and Kepler Update Dimitar Sasselov Department of Astronomy Origins of Life Initiative Harvard University Credit: S. Cundiff Exoplanets and the Planetary Origins of Life Life is a planetary phenomenon Life is a planetary phenomenon - origins To help us narrow down pre-biotic initial conditions, we need: - direct analysis of early-Earth samples – retrieved from the Moon, or - the broadest planetary context, beyond our Solar System, Exoplanets Outline: 1. Technical feasibility • Statistics: frequency of super-Earths & Earths • Remote sensing: successes & challenges • Opportunities to study pre-biotic environments 2. What should we do next – bio-signatures? • Yes, but are we prepared to interpret the spectra? • What to anticipate – geophysical cycles & UV light 3. Where geochemistry & biochemistry meet • Alternative biochemistries – do initial conditions matter? • Mirror life as a useful testbed to minimal cells. Burke et al (2013) Kepler mission: planets per star Statistical results to-date (22 months): many small planets (0.8 – 2 RE): > 40% of stars have at least one, with Porb < 150 days Fressin et al. (2013) Lest we forget… Credit: R. Murray-Clay 95 Planet Candidates Orbiting Red Dwarfs Dressing & Charbonneau (2013) & CharbonneauDressing M-Dwarf Planet Rate from Kepler • The occurrence rate of 0.4 – 4 REarth planets with periods < 50 days is 0.87 planets per cool star. • The occurrence rate of Earth-size planets in the habitable zone is 0.06 planets per cool star. • With 95% confidence, there is a transiting Earth- size planet in the habitable zone of a cool star within 31 pc. Dressing & Charbonneau (2013) Total in our Galaxy: All-sky yield: 6 ~ 200 x10 planets in HZ > 300 planets (0.9 – 2 RE) (0.9 – 2 RE) Earths and Super-Earths on the M-R Diagram Rp K-20b K-36b K-20f K-20e Mp Spectroscopy of exoplanet atmospheres Spectroscopy of an exoplanet (Hot Jupiter) (HD189733b) Identified: H2O, CO2, CH4, Song et al.
    [Show full text]
  • A Search for Prebiotic Signatures with the Mars 2020 Rover David Catling (U
    A search for prebiotic signatures with the Mars 2020 rover David Catling (U. Washington, Seattle) , +Tanja Bosak, Woody Fischer, John Grotzinger, Joel Hurowitz, Dimitar Sasselov, Roger Summons, John Sutherland, Jack NOTE ADDED BY JPL WEBMASTER: Szostak, & the Simons Collaboration on the This content has not been approved or adopted by NASA, Origins of Life JPL, or the California Institute of TechnoloGy. This document is = Group of organic chemists + biochemists + being made available for chemists + geoscientists + astronomers information purposes only, and any views and opinions expressed herein do not necessarily state or reflect those of NASA, JPL, or the California Institute of Technology. Overview • Motivation – Even if Mars didn't evolve life (no black shales yet!) it can provide insight into prebiotic chemistry: Consider for 2020 & sample return – Can we find traces of prebiotic feedstocks or biomolecules from prebiotic chemistry? This seems like an under-studied issue. Part 1) Environments for the origin of life – Little time here to weigh pros & cons of all proposed environments – We focus on an environment (lacustrine) that has the strongest experimental support of biomolecules made with specificity & yield Part 2) What to look for? Will discuss traces of ingredients and products of prebiotic chemistry. Part 3) Where to look? Lithologies of best preservation Part 1: Environments for Origin of Life The prebiotic is hidden on Hadean Earth from lack of rocks Do prebiotic traces exist on Noachian (4.1 to ~3.7 Ga) Mars? Darwinian evolution Post-Moon Stable Prebiotic RNA DNA in Black Photosynthetic impact ocean chemistry World cells shale life (stromatolites) 4.5 4.4-4.3 4.4 4.0 3.8 3.5 Billions of years ago (Ga) + arguments that an origin of life anywhere would have similar organic molecules: e.g., Pace (2001) The universal nature of biochemistry.
    [Show full text]