Arthropod expansion in morphological disparity following the Cambrian Explosion of Bilateria, as demonstrated by the Burgess Shale trilobite Olenoides and stem-Chelicerate Sidneyia. Image Credit: Smithsonian Institution, courtesy of Douglas Erwin.

A team of researchers including members of NAI's MIT team have married fossil records with molecular clock studies to reveal a new interpretation of the Cambrian explosion. Collectively these data allow an understanding of the environmental potential, genetic and developmental possibility, and ecological opportunity that existed before and during the Cambrian. The study compares the times of origin of major animal groups (from the molecular clock) with the times of their first appearance in the fossil record. The team shows that the major animal groups first diverged during the Cryogenian, roughly 300 million years prior to their appearance in the fossil record, and acquired the key components of their developmental toolkits early in their history. After a long lag, the groups' major ecological successes are reflected in the records of the Ediacaran and Cambrian. Their paper appears in the current issue of Science.

Posted by Keith Cowing at 12:53 PM | Permalink | Comments (0)

Scientists from NAI's New York Center for Astrobiology at Rensselaer Polytechnic Institute have used the oldest minerals on Earth to reconstruct the atmospheric conditions present on Earth very soon after its birth. The findings, which appear in the December 1, 2011 issue of Nature, are the first direct evidence of what the ancient atmosphere of the planet was like soon after its formation and directly challenge years of research on the type of atmosphere out of which life arose on the planet.

The scientists show that the atmosphere of Earth just 500 million years after its creation was not a methane-filled wasteland as previously proposed, but instead was much closer to the conditions of our current atmosphere. The findings, in a paper titled "The oxidation state of Hadean magmas and implications for early Earth's atmosphere," have implications for our understanding of how and when life began on this planet and could begin elsewhere in the universe.

For more information: http://astrobiology.nasa.gov/articles/earth-s-early-atmosphere-an-update/

Posted by Keith Cowing at 12:52 PM | Permalink | Comments (0)

Volcanic-hydrothermal flow channels offer a chemically unique environment, which at first glance appears hostile to life. It is defined by cracks in the crust of the earth, through which water flows, laden with volcanic gases are contacting a diversity of minerals. And yet - it is precisely this extreme environment, where the two mechanisms could have emerged, which are at the root of all life: The multiplication of biomolecules (reproduction) and the emergence of new biomolecules on the basis of previously formed biomolecules (evolution).

At the outset of this concatenation of reactions that led eventually to the formation of cellular forms of life there are only a few amino acids, which are formed from volcanic gases by mineral catalysis. Akin to a domino stone that triggers a whole avalanche, these first biomolecules stimulate not only their own further synthesis but also the production of wholly new biomolecules. "In this manner life begins by necessity in accordance with pre-established laws of chemistry and in a pre-determined direction", declares Guenter Waechtershaeuser, honorary professor for evolutionary biochemistry at the University of Regensburg. He developed the mechanism of a self-generating metabolism - theoretically, alas, an experimental demonstration has been lacking so far.

Continue reading "Mechanism of Evolution of the Primordial Metabolism Discovered" »

Posted by Keith Cowing at 2:51 PM | Permalink | Comments (0)

In the chemistry of the living world, a pair of nucleic acids--DNA and RNA--reign supreme. As carrier molecules of the genetic code, they provide all organisms with a mechanism for faithfully reproducing themselves as well as generating the myriad proteins vital to living systems.

Yet according to John Chaput, a researcher at the Center for Evolutionary Medicine and Informatics, at Arizona State University's Biodesign Institute(R), it may not always have been so.

Chaput and other researchers studying the first tentative flickering of life on earth have investigated various alternatives to familiar genetic molecules. These chemical candidates are attractive to those seeking to unlock the still-elusive secret of how the first life began, as primitive molecular forms may have more readily emerged during the planet's prebiotic era. One approach to identifying molecules that may have acted as genetic precursors to RNA and DNA is to examine other nucleic acids that differ slightly in their chemical composition, yet still possess critical properties of self-assembly and replication as well as the ability to fold into shapes useful for biological function.

According to Chaput, one interesting contender for the role of early genetic carrier is a molecule known as TNA, whose arrival on the primordial scene may have predated its more familiar kin. A nucleic acid similar in form to both DNA and RNA, TNA differs in the sugar component of its structure, using threose rather than deoxyribose (as in DNA) or ribose (as in RNA) to compose its backbone.

In an article released online today in the journal Nature Chemistry, Chaput and his group describe the Darwinian evolution of functional TNA molecules from a large pool of random sequences. This is the first case where such methods have been applied to molecules other than DNA and RNA, or very close structural analogues thereof. Chaput says "the most important finding to come from this work is that TNA can fold into complex shapes that can bind to a desired target with high affinity and specificity". This feature suggests that in the future it may be possible to evolve TNA enzymes with functions required to sustain early life forms.

Continue reading "Did an Earlier Genetic Molecule Predate DNA and RNA?" »

Posted by Keith Cowing at 3:29 PM | Permalink | Comments (0)

The Institute for Astronomy (IfA) invites applications for a Postdoctoral Fellowship with interests in the origin of Earth's water to work with the University of Hawai'i's NASA Astrobiology Institute lead team (see http://www.ifa.hawaii.edu/UHNAI/). The UH lead team maintains an innovative and multi-disciplinary research environment linking astronomical, biological, microbiological, chemical, and geological sciences to investigate the origin, history, distribution and role of water as it relates to life in the universe. The program centers around interactions with an interdisciplinary group of postdoctoral fellows. We have a particular need for an individual interested in the origin of Earth's water, and, by analogy, terrestrial planetary volatiles. The work involves geological field work to sample primitive, deep-mantle-plume materials, preparation of samples of melt inclusions in olivines from Hawaiian and Icelandic basalts for isotopic measurements using the petrographic microscope, scanning electron microscope, and electron microprobe, and measurements of D/H ratios and hydrogen abundances in the melt inclusions using the UH Cameca ims 1280 ion microprobe. The Fellowship is for one year and may be renewable up to a total of 3 years assuming satisfactory progress and continued availability of funds. The fellow will receive a stipend of approximately $5,000 per month, a small relocation allowance and basic research costs.

Continue reading "Origin of Earth's Water - Astrobiology Postdoctoral Fellow - Institute for Astronomy, University of Hawai'i Manoa" »

Posted by Keith Cowing at 12:12 AM | Permalink | Comments (0)

Among the various geochemical proxies for the presence of molecular oxygen in the environment, molecular fossils offer a unique record of oxygen where it was first produced and consumed by biology: in sunlit aquatic habitats. Steroid biosynthesis requires molecular oxygen, making the study of sterane molecular fossils important in reconstructing early environmental conditions. In a new study, NAI-funded scientists and their colleagues present evidence that microaerobic marine environments where steroid biosynthesis was possible could have been widespread and persistent for long periods of time prior to the earliest evidence for atmospheric oxygen. Their study is published in a recent issue of PNAS.

Source: NAI newsletter

Posted by Keith Cowing at 8:30 PM | Permalink | Comments (0)

Fossils are essential to our understanding of the history and origins of complex life. New work from NAI's MIT and Penn State teams describes exquisitely preserved microfossils from mid-Neoproterozoic (811-717 million years old) rocks of the Fifteenmile Group, Yukon. These fossils are interpreted as biomineralized plates that covered the surface of a single-celled alga.

Their findings suggest that the minerals used by the ancient marine organisms have changed through time, perhaps linked to changing ocean chemistry. While the relationship of these fossils to modern organisms is difficult to determine, the researchers argue that it's likely that these unique fossils are the plates of an organism most closely related to green algae. Their paper appears online in Geology.

Posted by Keith Cowing at 4:37 PM | Permalink | Comments (0)

In recent years, scientists have found evidence that a 'near complete' biological nitrogen cycle existed in the oceans during the late Archean to early Proterozoic (from 2.5 to 2 billion years ago). Modern bacteria use an enzyme called nitrogenase to cycle nitrogen from one form to another. This enzyme is dependent on the presence of metallic elements like iron (Fe), vanadium (V) and, most often, molybdenum (Mo). However, ancient oceans didn't contain much molybdenum. Could Fe-nitrogenase or V-nitrogenase have played a larger role in the archaean oceans than they do today?

To answer this question, a team of researchers at NAI's Montana State University and Arizona State University teams studied the phylogenetic relationships between the proteins that allow nitrogenase to interact with each of the three elements. Their results suggest that the protein (known as Nif protein) actually developed in methanogenic microorganisms, and was then incorporated into bacteria by lateral gene transfer around 1.5-2.2 billion years ago.

Ultimately, if Mo-nitrogenase originated under anoxic conditions in the Archaean, it would have likely happened in an environment where both methanogens and bacteria coexisted, and where molybdenum was present for at least part of the time.

The emergence of enzymes like Mo-nitrogenase was a significant step in the evolution of life, and had powerful repercussions for planet Earth and its biosphere as a whole. This research can help answer important questions about the environmental conditions that were present on the early Earth, and the interactions that occurred between life and the ancient planet.

The results were published in the May edition of the journal Geobiology

Posted by Keith Cowing at 11:15 AM | Permalink | Comments (0)

Researchers supported in part by the NASA Astrobiology Institute and the NASA Exobiology & Evolutionary Biology program have used computer models to study the potential of organic sulfur compounds to be biosignatures in exoplanetary atmospheres. The results indicate that the most detectable feature involves levels of ethane that are higher than expected based on a target planet's methane concentration. These detection techniques will be particularly useful for finding life on planets similar to the early Earth, that do have life but do not have atmospheric oxygen or ozone, two major biosignature gases. The team suggests that a mission that can detect the ethane and methane in exoplanet atmospheres could find life on such planets, thereby increasing our chances of finding a habitable world outside our solar system.

The study was recently published in the journal Astrobiology and is now available online.

Posted by Keith Cowing at 12:42 AM | Permalink | Comments (0)

Fossils are essential to our understanding of the history and origins of complex life. New work from NAI's MIT and Penn State teams describes exquisitely preserved microfossils from mid-Neoproterozoic (811-717 million years old) rocks of the Fifteenmile Group, Yukon. These fossils are interpreted as biomineralized plates that covered the surface of a single-celled alga.

Their findings suggest that the minerals used by the ancient marine organisms have changed through time, perhaps linked to changing ocean chemistry. While the relationship of these fossils to modern organisms is difficult to determine, the researchers argue that it's likely that these unique fossils are the plates of an organism most closely related to green algae. Their paper appears online in Geology.

Posted by Keith Cowing at 11:36 AM | Permalink | Comments (0)

Ancient rocks are shedding new light on the timeline for life's emergence on Earth. The rocks from the Nuvvuagittuq Supracrustal Belt in Quebec, Canada, are believed to be some of the oldest on Earth. They contain carbon-based minerals that had been interpreted as evidence of the Earth's early biosphere, however, new research tells a different story. By applying cutting-edge technology to the rock samples, a team of scientists have revealed that the carbon minerals found in the rocks may be much younger than the rocks themselves.

"The characteristics of the poorly crystalline graphite within the samples are not consistent with the metamorphic history of the rock," said co-author Dominic Papineau in a news release from Boston College. "The carbon in the graphite is not as old as the rock. That can only ring a bell and require us to ask if we need to reconsider earlier studies."

The results were reported in the May 15, 2011 edition of the journal Nature Geoscience. Funding organizations for this work included the NASA Exobiology and Evolutionary Biology Program (Exo/Evo), the NASA Astrobiology Institute (NAI), the W.M. Keck Foundation, the Geophysical Laboratory of the Carnegie Institution of Washington, Carnegie of Canada, the Naval Research Laboratory, the NRC Research Associateship Program, Boston College, and the Fond Quebecois pour la recherche sur la nature et les technologies (FQRNT).

Posted by Keith Cowing at 11:35 AM | Permalink | Comments (0)

Researchers supported in part by the NASA Astrobiology Institute and the NASA Exobiology & Evolutionary Biology program have used computer models to study the potential of organic sulfur compounds to be biosignatures in exoplanetary atmospheres. The results indicate that the most detectable feature involves levels of ethane that are higher than expected based on a target planet's methane concentration. These detection techniques will be particularly useful for finding life on planets similar to the early Earth, that do have life but do not have atmospheric oxygen or ozone, two major biosignature gases. The team suggests that a mission that can detect the ethane and methane in exoplanet atmospheres could find life on such planets, thereby increasing our chances of finding a habitable world outside our solar system.

The study was recently published in the journal Astrobiology and is now available online.

Posted by Keith Cowing at 12:17 AM | Permalink | Comments (0)

May 12-13, 2011

A two-day workshop using NAI remote communications tools will be held on May 12th and 13th, 2011. Organized by Chris Dupont of the J. Craig Venter Institute, along with John Peters and Ariel Anbar, leaders of the Montana State University and Arizona State University NAI teams, respectively.

Anticipated presentation topics include:

* Spatial and temporal dynamics of ocean redox chemistry
* Molecular biomarkers: biological role and usage as a proxy
* The evolution of phytoplankton
* The last universal common ancestor
* Applications of synthetic biology in paleobiology
* Modern day analogs of ancient environments
* The evolution of metabolic pathways

The workshop will consist of talks and discussion. Each presentation will allow ample time for questions and answers afterwards. Although talks will be recorded and posted online at scivee.tv, we encourage researchers to attend in real time to engage in what we expect will be a lively exchange of ideas during the workshop.

While many of the speakers have been confirmed, time has been set aside for four to six shorter contributed talks. Travel and hotel costs will be covered for those giving contributed talks. In addition, it is anticipated that funds for several more travel grants will be available. If interested in attending or giving a contributed talk, please email Chris Dupont (cdupont@jcvi.org) your contact information and an abstract or reason for attending. Selection of talks and travel grants will begin April 1st. Preference will be given to younger scientists.

Workshop Organizing Committee

* Chris Dupont, J. Craig Venter Institute
* Ariel Anbar, Arizona State University
* John Peters, Montana State University

For more information and participation instructions, visit: http://astrobiology.nasa.gov/nai/geobiology2011

Source: NAI Newsletter

Posted by Keith Cowing at 10:31 PM | Permalink | Comments (0)

Application Deadline: February 15, 2011

Roger Summons, PI of the MIT NAI team, is planning a field trip to Shark Bay Australia from June ~11 - 19. Participants include Pieter Visscher (UConn), Joan Bernhard and Ginny Edgcomb (WHOI) and students from MIT and the University of NSW. They will be exploring the microbial diversity of subtidal stromatolites. The team could accommodate another one or two students wishing to participate in related research activities. They must have their own funding support, and should supply a short description of the research they plan to conduct to rsummons@mit.edu.

Posted by Keith Cowing at 7:26 PM | Permalink | Comments (0)

The next meeting of the Committee on the Origins and Evolution of Life (COEL) will be held March 2-4, 2011 at the Keck Center in Washington, D.C. COEL is the standing committee of the Space Studies Board that organizes and provides oversight of studies on research opportunities and programs on the origin and evolution of life in the universe, including NASA's astrobiology program. As usual, most of the committee's sessions are open to the community.

For more information, see http://sites.nationalacademies.org/SSB/ssb_052326 or contact COEL's Senior Program Officer, David H. Smith (DSmith@nas.edu). [Source: NAI Newsletter]

Posted by Keith Cowing at 11:00 PM | Permalink | Comments (0)

Through NAI's Minority Institution Research Support Program, scientists at the University of Puerto Rico and their collaborators have identified a unique record of an ancient meteorite impact event that is preserved in microstructures in detrital grains of quartz, zircon, and monazite in the Vaal River, South Africa. The sand samples were collected from the channel of the Vaal River near the two billion-year old Vredefort Dome impact structure, where impact-shocked minerals are known to occur in rocks.

This is the first report that impact shock-deformed minerals survive the process of uplift, erosion, and sedimentary transport. The unique mineral shock-deformation was documented by scanning electron microscopy at the University of Puerto Rico and the University of Wisconsin. The team's results are published in the current issue of the GSA Bulletin.

This result demonstrates that a record of an ancient impact event can be preserved in sedimentary rocks billions of years after the impact crater is eroded. This recognition provides a new method to search for evidence of missing impacts in sedimentary rocks throughout the geologic time scale. This new insight may lead to the identification of missing impact events that have been hypothesized to cause biological mass extinctions, and also impact events on the early Earth that may have influenced the rise of life. [Source: NAI Newsletter]

Posted by Keith Cowing at 10:45 PM | Permalink | Comments (0)

A three-day workshop using NASA Astrobiology Institute (NAI) remote communications tools, on "Molecular Paleontology and Resurrection: Rewinding the Tape of Life," will be held on 8, 9 & 10 November 2010. Real-time participation requires only an internet connection and is available to interested scientists from around the world. Participants will discuss "top down" origin of life research, which will ultimately allow us to rewind the evolutionary record of biochemical processes and assemblies.

Organized by John Peters and Loren Williams, PIs of the NAI's Montana State University and Georgia Tech teams, a primary goal of the workshop is to foster new interdisciplinary collaborations across the community.

Session topics will include

* Phylogenetic Studies on Key Enzymes Involved in Information Pathways and Metabolism
* The Evolutionary History of Protein Synthesis
* Minerals to Enzymes, Bridging the Gap Between Metal-Based Abiotic and Biological Chemistry
* Phylogenetic Reconstruction/Resurrection, A Glimpse into Extinct Biochemistry
* What Can Modern Biological Energy Transformation Systems Tell Us About Conditions on the Early Earth?
* Linking the Evolutionary Record to the Geological Record

The workshop is open to the worldwide science community and is accessible via internet browser. To receive information on how to connect to the workshop, register on the NAI website: http://astrobiology.nasa.gov/nai/ool-www/ . [Source: NAI]

Posted by Keith Cowing at 10:33 AM | Permalink | Comments (0)

The International Academy of Astronautics (IAA) will hold a symposium on "Searching for Life Signatures" at the Kavli Royal Society International Centre in the UK on October 6-8, 2010. The IAA symposium will immediately follow a Royal Society meeting "Towards a Scientific and Societal Agenda on Extra-terrestrial Life," also at the Kavli Centre on October 4-5. A Call for Papers for the IAA symposium, including information on the Royal Society meeting, can be found at http://iaaweb.org/content/view/413/572/ The deadline for abstract submission to the IAA symposium is June 15. [Source: NAI Newsletter]

Posted by Keith Cowing at 10:59 AM | Permalink | Comments (0)

Workshop Dates: October 11-13, 2010

NAI, together with the Agouron Institute and the Canadian Institute for Advanced Research, are again sponsoring a field workshop of the Early Earth Focus Group following upon the very successful BAR (Biosignatures in Ancient Rocks) workshop of 2007. The topic of this workshop is Anoxygenic Phototrophic Ecosystems (APE): Ancient and Modern. This workshop will bring together approximately 40 microbial ecologists, astro- and geobiologists; including ~10 senior scientists who have made significant contributions to our understanding of modern and ancient anaerobic ecosystems and of the chemistry of ancient oceans, ~15 early career researchers (assistant professors and postdocs) who have been actively conducting forefront research, and ~15 future leaders (current graduate students) in this field. The workshop is scheduled for Oct. 11-13 in Fayetteville, New York, at the scenic and biogeochemically stratified Green Lake. Travel awards are available. Please contact Linda Altamura (Penn State Astrobiology Research Center: lxg2@psu.edu) for further information.

For more information about the Early Earth Focus Group, visit: http://astrobiology.nasa.gov/nai/focus-groups/current/early-earth/intro/ [Source: NAI Newsletter]

Posted by Keith Cowing at 9:03 PM | Permalink | Comments (0)

The Ediacaran Period (635-542 million years ago) was a time of fundamental environmental and evolutionary change, culminating in the first appearance of macroscopic animals. A new study from NAI's Arizona State University Team outlines a detailed record of Ediacaran ocean chemistry for the Doushantuo Formation in the Nanhua Basin, South China. Their results suggest a stratified ocean was maintained dynamically throughout the Ediacaran Period. Their model reconciles seemingly conflicting geochemical conditions proposed previously for Ediacaran deep oceans, and helps explain the patchy fossil record of early metazoans. Their paper appears in the April 2nd issue of Science.

[Source: NAI Newsletter]

Posted by Keith Cowing at 5:57 PM | Permalink | Comments (0)

Studies of modern sedimentary analogs to ancient rock precursors are critical to gain insight into the biogeochemical processes responsible for generating unique chemical or isotopic compositions in ancient rocks. A recent study published by the University of Wisconsin NAI Team in Geobiology provides an example of such a modern analog study in the context of Archean and Paleoproterozoic Banded Iron Formations (BIFs). Sediments downstream of the Iron Mountain acid mine drainage site in northern California were examined for their chemical and Fe isotope composition, as well as the presence and activity of iron-reducing microorganisms. The results link dissimilatory microbial iron reduction (DIR) to the generation of large quantities of aqueous (mobile) ferrous iron, and provide the first demonstration of Fe isotope fractionation in an environment where DIR has been shown by microbiological methods to be active in sediment metabolism. These findings provide insight into pathways whereby DIR could have led to the formation of isotopically-light Fe-bearing minerals in BIFs.

[Source: NAI Newsletter]

Posted by Keith Cowing at 5:53 PM | Permalink | Comments (0)

Date/Time: Monday, June 7, 2010 11:00AM Pacific
Speaker: Katrina Edwards (University of Southern California)
Title: "Intraterrestrial Life on Earth"

In 1986, scientists sailing in the Pacific Ocean made an astonishing discovery. In sediments collected from 850m below the seafloor, they identified that microbes were living and thriving in an environment not previously known to contain life. This discovery has spawned a new field of research on the "deep biosphere" with researchers exploring how life persists and evolves at hostile temperatures and pressures. With estimates that the sub-seafloor may contain as much two-thirds of the Earth's microbial population, research today focuses on understanding the importance, or lack thereof, of this community to the Earth's systems. This presentation will focus on the current state of knowledge with respect to the deep biosphere and the major questions being addressed in this field, such as what are the nature and extent of life on Earth? What are the physico-chemical limits of life on Earth? How metabolically active is the deep biosphere, and what are the most important redox processes? What are the dispersal mechanisms for life in the deep biosphere? How does life evolve in deeply buried geological deposits that can occur more than a km beneath the ocean floor? What is the influence of the deep biosphere on global-scale biogeochemical processes?

For more information and participation instructions: http://astrobiology.nasa.gov/nai/seminars/detail/174

[Source: NAI Newsletter]

Posted by Keith Cowing at 8:01 PM | Permalink | Comments (0)

This two week summer course will be held in Utrecht, The Netherlands at the Universiteit Utrecht from July 5-16, 2010.

The history of life on earth can be studied by its fossil record. In this approach, each fossil is seen as a window into evolutionary history and paleoecology. Importantly, fossils provide us with essential information about the age of the layers they are found in. Moreover they comprise our single most valuable source of information on the environment in the past. Fossils ranging from marine micro-organisms to large terrestrial vertebrates are thus used as tools to reconstruct time, evolutionary history, climate, and ancient environments. In this course several fossil groups will be discussed and their practical applications will be explored.

A general introduction on the use of fossils to reconstruct time (biostratigraphy) will be followed by lectures on marine invertebrate paleontology, micropaleontology, vertebrate paleontology and plant remains. An important part of the course will consist of hands-on exercises where you will learn how to use fossils for age determination and for environmental reconstruction. Fossil rodents are used to demonstrate how to correlate and date fossil faunas. You will investigate the evolutionary history of marine invertebrates, based on their changing morphology. Marine micro-organisms and plant remains will be employed to reconstruct ecology and environment. Finally, Mesozoic vertebrates (251-65 Ma) are used to demonstrate morphological adaptations to changing environments. The lectures and excersises will be given by staff and guests of the Department of Earth Sciences. The recreational programme will be organised by student societies and the Erasmus network.

This summer school is held under the auspices of the Graduate School of Geosciences.

For more information: http://www.utrechtsummerschool.nl/index.php?type=courses&code=H19 [Source NAI newsletter]

Posted by Keith Cowing at 11:40 PM | Permalink | Comments (0)

Researchers from NAI's University of Wisconsin Team studied carbon and iron isotopes in core samples from 2.7-2.5 billion year old rocks in Western Australia. New iron isotope data integrated with previously collected carbon isotope data on the same samples document the sophisticated metabolic diversity of microbial communities that once lived in the region, showing that methane and iron cycling were likely coupled. Their results are published in a recent issue of Earth and Planetary Science Letters. [Source NAI newsletter]

Posted by Keith Cowing at 10:46 PM | Permalink | Comments (0)

It is widely accepted that around 2.4 billion years ago, the Earth's atmosphere underwent a dramatic change when oxygen levels rose sharply. Called the "Great Oxidation Event" (GOE), the oxygen spike marks an important milestone in Earth's history, the transformation from an oxygen-poor atmosphere to an oxygen-rich one paving the way for complex life to develop on the planet.

Two questions that remain unresolved in studies of the early Earth are when oxygen production via photosynthesis got started and when it began to alter the chemistry of Earth's ocean and atmosphere.

Continue reading "Oxygen Production in Earth's Early Oceans Predates the Great Oxidation Event" »

Posted by Keith Cowing at 10:13 PM | Permalink | Comments (0)

November 25-27, 2009 in Frascati, Italy - The NASA Mars Program Office has announced that travel funding will be made available for as many as 5 students who are U.S. citizens or legal residents, with Mars-related interests, to attend the Workshop on Methane on Mars: Current Observations, Interpretation and Future Plans, November 25-27, 2009 in Frascati, Italy. An application must be submitted by September 28, 2009, to be considered for this funding. NASA Headquarters will make the selections and students will be notified no later than October 15, 2009. Reimbursable costs include registration fees, transportation (airfare, mileage to/from airport, parking, rental car) and lodging/per diem. In most cases, actual expenses will exceed the funding provided.

Continue reading "Student Travel Grants - Workshop on Methane on Mars" »

Posted by Keith Cowing at 9:50 AM | Permalink | Comments (0)

Humans might not be walking on Earth today if not for the ancient fusing of two microscopic, single-celled organisms called prokaryotes, NASA-funded research has found.

By comparing proteins present in more than 3000 different prokaryotes - a type of single-celled organism without a nucleus - molecular biologist James A. Lake from the University of California at Los Angeles' Center for Astrobiology showed that two major classes of relatively simple microbes fused together more than 2.5 billion years ago. Lake's research reveals a new pathway for the evolution of life on Earth. These insights are published in the Aug. 20 online edition of the journal Nature.

This endosymbiosis, or merging of two cells, enabled the evolution of a highly stable and successful organism with the capacity to use energy from sunlight via photosynthesis. Further evolution led to photosynthetic organisms producing oxygen as a byproduct. The resulting oxygenation of Earth's atmosphere profoundly affected the evolution of life, leading to more complex organisms that consumed oxygen, which were the ancestors of modern oxygen-breathing creatures including humans.

Continue reading "NAI Research Reveals Major Insight into Evolution of Life on Earth" »

Posted by Keith Cowing at 9:54 PM | Permalink | Comments (0)

May 21 - 23, 2010 Denver, Colorado and Dinosaur Ridge, Cretaceous Dakota Sandstone, Denver

The conference presents an important and novel review on microbial mats and the sedimentary structures they form in siliciclastic settings through Earth times, from the early Archean to the present. The meeting brings together the expertise and knowledge of an international panel of leading researchers to provide a state-of-the art overview of the field. The participants give a timely review of the current and most topical areas of research, essential for all scientists interested in this rapidly growing field. For more information: http://www.sepm.org/activities/researchconferences/microbial/microbial_home.htm Source: NAI Newsletter

Posted by Keith Cowing at 10:07 PM | Permalink | Comments (0)

Session Abstract: During most of the geologic past, life and the surface environments on Earth were profoundly different than they are today. In particular, it is generally accepted that the atmosphere was devoid of O2, or nearly so, until the "Great Oxidation Event" approximately 2.4 billion years ago. However, considerable uncertainty remains about the abundances of O2 and other oxidants during the first half of Earth history, as well as processes that constrained these abundances to seemingly trace levels. Emerging data should allow tighter constraints on Archean free oxygen concentrations, the variability of redox conditions at high temporal resolution, and the evolutionary and biogeochemical consequences of oxygenation. At the same time there is a need to refine existing proxies, assess their limitations, and develop new ones. This session will explore these issues. We encourage abstracts from a variety of areas ranging from analytical and theoretical geochemistry to genomics. For more information see
http://www.agu.org/meetings/fm09/program/scientific_session_search.php?show=detail&sessid=219 Source: NAI Newsletter

Posted by Keith Cowing at 10:01 PM | Permalink | Comments (0)

The 39+/-2Ma Haughton impact structure on Devon Island comprises a thick target succession of sedimentary rocks, mainly carbonates. The carbonates contain pre-impact organic matter, including fossil biological markers. Haughton is located in an area where no major thermal event has affected the sedimentary succession after heating caused by impact. This makes Haughton uniquely suitable for studies concerning the preservation of fossil biological markers following an impact event.

Continue reading "Preservation of Biological Markers in Clasts Within Impact Melt Breccias from the Haughton Impact Structure, Devon Island" »

Posted by Keith Cowing at 2:25 PM | Permalink | Comments (0)

NAI's Archean Biosphere Drilling Project supported the acquisition of pristine drill core samples obtained from ancient rocks in Western Australia. New results from those studies, published in the current issue of Nature Geoscience, point toward an earlier start for oxygenic photosynthesis on the early Earth than previously thought.

Continue reading "New Evidence for an Earlier Origin of Oxygenic Photosynthesis" »

Posted by Keith Cowing at 11:02 AM | Permalink | Comments (0)

Never before has an asteroid been both telescopically observed while in space, and then collected and analyzed after it's hit the Earth. NAI astrobiologists from the Carnegie Institution of Washington and the SETI Institute are part of the large, interdisciplinary team of scientists who undertook the investigation. Their results are published in a recent issue of Nature.

Analysis of the carbon content in the fragments of 2008 TC3, as it is known, showed it to be mostly graphite-like, indicating that at some point in the past the body had been subjected to extremely high temperatures. Nanodiamonds were also observed.

It's oxygen isotopic signature classifies it as a very rare type of meteorite known as a ureilite. Because astronomers took spectral measurements of 2008 TC3 before it hit the Earth, and can compare those measurements with the laboratory analyses, scientists will be better able to recognize ureilite asteroids in space.

[Source: NAI Newsletter]

Posted by Keith Cowing at 11:01 AM | Permalink | Comments (0)

NAI's Deep Time Drilling Project supported the drilling of several pristine cores from ancient rocks in Western Australia in 2004, and a new paper in Science, led by University of Washington astrobiologists, outlines results from the analysis of these cores. The nitrogen isotope values in the core from the 2.5-billion-year-old Mount McRae Shale vary over 30 meters, evidently recording a temporary change from an anaerobic to an aerobic nitrogen cycle, and back again to anaerobic. Other data suggest that nitrification occurred in response to a small increase in surface-ocean oxygenation. The data imply that nitrifying and denitrifying microbes had already evolved by the late Archean and were present before oxygen first began to accumulate in the atmosphere.

[Source: NAI Newsletter]

Posted by Keith Cowing at 12:10 AM | Permalink | Comments (0)

Members of NAI's Carnegie Institution of Washington, Indiana University, and NASA Goddard Space Flight Center Teams and their colleagues have revisited the Miller-Urey experiments, and found some surprising results.

A classic experiment proving amino acids are created when inorganic molecules are exposed to electricity isn't the whole story, it turns out. The 1953 Miller-Urey Synthesis had two sibling studies, neither of which was published. Vials containing the products from those experiments were recently recovered and reanalyzed using modern technology. The results are reported in Science.

Continue reading "Miller-Urey Revisited" »

Posted by Keith Cowing at 8:15 PM | Permalink | Comments (0)

An ecosystem discovered 2.8 kilometers underground in the Mponeng Gold Mine near Johannesburg, South Africa two years ago has now been shown to comprise only a single species of microbe, existing on energy from radioactivity, completely independently of the Sun. The community of rod-shaped bacteria of the species Desulforudis audaxviator was discovered in 2005-06 by members of the NAI's Indiana-Princeton-Tennessee Astrobiology Initiative (IPTAI) Team. Their current results are presented in the October 10th issue of Science.

Continue reading "Life Without the Sun" »

Posted by Keith Cowing at 8:17 PM | Permalink | Comments (0)

Members of NAI's Penn State, Carnegie Institution, and MIT teams report in a recent issue of Earth and Planetary Science Letters, the distribution of biomarkers in 2.72-2.56 billion-year-old, Neoarchean rocks from the Hamersley Province on the Pilbara Craton in Western Australia. Their observations are consistent with a cyanobacterial source for 2-methylhopanes, in which cyanobacteria were likely the cornerstone of microbial communities in shallow-water ecosystems providing molecular oxygen, fixed carbon, and possibly fixed nitrogen.

Their data, revealing relative abundances of 3-methylhopanes, but not 2-methylhopanes, strongly correlate to stable carbon isotopic composition of insoluble particulate organic matter (kerogen). The unanticipated nature of this relationship provides evidence for a shallow-water locus of carbon cycling through aerobic oxidation of methane and, coincidentally, a means to demonstrate biomarker syngenicity.

Source: NAI Newsletter

Posted by Keith Cowing at 7:03 PM | Permalink | Comments (0)

NAI's University of Wisconsin team presents a review of iron isotope fingerprints created through biogeochemical cycling in the May, 2008 issue of The Annual Review of Earth and Planetary Sciences. This landmark paper brings together for the first time the co-evolution records of photosynthesis, bacterial sulfate reduction, and bacterial iron reduction in the early Earth. They review data on natural systems and experiments, looking at both abiological and biological processes, and conclude that the temporal carbon, sulfur, and iron isotope record reflects the interplay of changing microbial metabolisms over Earth's history. [Source: NAI Newsletter]

Posted by Keith Cowing at 6:05 PM | Permalink | Comments (0)

Astrobiology December 2007, 7(6): 1023-1032

http://www.liebertonline.com/doi/pdfplus/10.1089/ast.2006.0091

The shallow habitable region of cratonal crust deforms with a strain rate on the order of 1019 s1. This is rapid enough that small seismic events are expected on one-kilometer spatial scales and one-million-year timescales. Rock faulting has the potential to release batches of biological substrate, such as dissolved H2, permitting transient blooms.

Continue reading "Did Earthquakes Keep the Early Crust Habitable?" »

Posted by Keith Cowing at 9:48 AM | Permalink | Comments (0)

Researchers from NAI's University of Hawai'i Team and their colleagues have a new paper in Geobiology reviewing recent work on the climatic, geochemical, and ecological events that preceded animal fossils, considering their portent for metazoan evolution. They also consider recent published research on the nature and chronology of the earliest fossil record of metazoans, and on the molecular-based analysis that yielded dates older than the last 35 million years of the Precambrian for the appearance of major animal groups.

[Source: NAI Newsletter]

Posted by Keith Cowing at 8:48 PM | Permalink | Comments (0)

The goal of research funded under the interdisciplinary P2C2 solicitation is to utilize key geological, chemical, and biological records of climate system variability to provide insights into the mechanisms and rate of change that characterized Earth's past climate variability, the sensitivity of Earth's climate system to changes in forcing, and the response of key components of the Earth system to these changes.

Continue reading "NSF Funding Opportunity: Paleo Perspectives on Climate Change (P2C2)" »

Posted by Keith Cowing at 8:45 PM | Permalink | Comments (0)

NAI's Astrobiology Drilling Program supported researchers in 2004 to obtain subsurface core samples from the Hamersley Basin in Western Australia. Those samples, representing the time just before the Great Oxidation Event, have been analyzed, and two research papers detailing the results (Anbar, et al. and Kaufman, et al.) appear in September 28, 2007 issue of Science. Both groups found unexpected, correlated changes that reveal the presence of small but significant amounts of O2 in the environment 2.5 billion years ago, ~50-100 milion years before the Great Oxidation Event, and a shift from lower O2 abundance prior to that time. [Source: NAI Newsletter]

Posted by Keith Cowing at 12:00 PM | Permalink | Comments (0)

Researchers from NAI's Carnegie Institution of Washington Team have a paper in Nature describing evidence that Earth's Mesoarchean atmosphere (3.2 and 2.8 Gya) possessed very low amounts oxygen. These findings contrast with prior claims that Earth's atmosphere underwent its first rise in oxygen during the Mesoarchean, and indicate that oxygen first rose above parts per million levels sometime between 2.45 and 2.4 billion years ago. [Source: NAI Newsletter]

Posted by Keith Cowing at 12:01 PM | Permalink | Comments (0)

NAI's Marine Biological Laboratory Team has a new paper in Science detailing aspects of population structure for microbial communities at two neighboring hydrothermal vents. Using environmental DNA sequencing techniques, they found the two populations reflect the geochemical conditions of each vent. [Source: NAI Newsletter]

Posted by Keith Cowing at 12:00 PM | Permalink | Comments (0)

Biomarkers in rocks prior to the rise in Earth's atmospheric oxygen 2.5 billion years ago show cyanobacteria released oxygen at the same levels as today. What was happening to that oxygen? A new paper in Nature from NAI's Penn State Team proposes that the rise of atmospheric oxygen occurred because the predominant sink for oxygen--enhanced submarine volcanism--was abruptly and permanently diminished during the Archaean-Proterozoic transition by a shift from predominantly submarine volcanism to a mix of subaerial and submarine volcanism.

Source: NAI Newsletter

Posted by Keith Cowing at 7:41 AM | Permalink | Comments (0)

An international team of researchers, including members of NASA Astrobiology Institute's (NAI) Virtual Planetary Laboratory team used NASA's Spitzer Space telescope to detect the presence of water vapor on the hot Jupiter Henry Draper (HD) Catalog 189733b. (The "b" after the number indicates that the reference is to a planet circling the star with that number.)

This is significant because several attempts to detect water on such planets either failed to find compelling evidence or made it clear that their claims should not be taken as fact. An article about this study was published recently in Nature magazine. The study's primary author, Giovanna Tinetti was a 2003 NAI Postdoctoral Fellow.

Posted by Keith Cowing at 11:03 AM | Permalink | Comments (0)

This new video from JPL shows how NASA astrobiologists are gathering exciting clues that will help them pick the best spots to search for possible signs of life beyond Earth. http://www.jpl.nasa.gov/videos/phoenix/phx20070724/ [Source: NAI Newsletter]

Posted by Keith Cowing at 12:17 PM | Permalink | Comments (0)

Deep inside a flooded mine in Wisconsin, scientists from NAI’s University of California, Berkeley Team have discovered an environment in which bacteria emit proteins that sweep up metal nanoparticles into immobile clumps. Their finding may lead to innovative ways to remediate subsurface metal toxins, and have exciting implications for identifying biosignatures on Earth and other worlds. The research, published in the June 14th issue of Science, was done in collaboration with a team from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory. [Source: NAI Newsletter]

Posted by Keith Cowing at 8:26 AM | Permalink | Comments (0)

Jennifer Heldmann has been invited to participate in a special COSPAR Colloquium on Mars Special Regions. This meeting is an essential step in developing an international consensus on the definition of "special" regions on Mars, which will in-turn determine the application of planetary protection requirements for future Mars lander missions. This 3-day meeting will take place in Rome, Italy on 18-20 September 2007. For more on COSPAR Colloquia visit: http://cosparhq.cnes.fr/Meetings/Colloq.htm

Posted by Keith Cowing at 4:17 PM | Permalink | Comments (0)

A NASA Astrobiology Institute Field Workshop "Biosignatures in Ancient Rocks (BAR)" will be held during September 18-28 in Ontario, Canada. See the details at http://psarc.geosc.psu.edu/RESEARCH/New_Conference/Ontario_new.htm [Source: NAI Newsletter]

Posted by Keith Cowing at 3:49 PM | Permalink | Comments (0)

NAI scientists from the Carnegie Institution of Washington Team and their colleagues have a new paper in Geology outlining their process in resolving the mysterious identity of the Devonian fossil organism Prototaxities as a fungus. The team analyzed carbon isotopic ratios of the fossil relative to plants that lived in the same environment 400 million years ago. [Source: NAI Newsletter]

Posted by Keith Cowing at 3:51 PM | Permalink | Comments (0)

UW Seminar: Four Billion Years of Climate Change (Lessons from the Precambrian): From Oxygen Poisoning to Snowballs & True Polar Wander Presenter: Joe Kirschvink

Date/Time: 5/29/2007 02:30 PM PDT

Continue reading "Seminar" »

Posted by Keith Cowing at 3:48 PM | Permalink | Comments (0)

Multidisciplinary work from members of NAI's SETI Institute Team and a host of collaborators across the NAI re-examines what is known at present about the potential for a terrestrial planet forming within, or migrating into, the classic liquid–surface–water habitable zone close to an M dwarf star. Their new paper, published in the current issue of Astrobiology, presents the summary conclusions of an interdisciplinary workshop sponsored by NAI and convened at the SETI Institute in 2005. [Source: NAI Newsletter]

Posted by Keith Cowing at 10:58 PM | Permalink | Comments (0)

Differently colored plants may live on extra-solar planets, according to two new papers in the current issue of Astrobiology authored by members of NAI's Virtual Planetary Laboratory Alumni Team and their colleagues. They took previously simulated planetary atmospheric compositions for Earth-like planets orbiting various star types (including M stars), generated spectra, and found that photosynthetic pigments may peak in absorbance in the blue for some star types, and red-orange and near-infrared for others. Their results also suggest that, under water, organisms would still be able to survive ultraviolet flares from young M stars and acquire adequate light for growth - which greatly increases the scope for habitability in these systems. [Source: NAI Newsletter]

Posted by Keith Cowing at 10:57 PM | Permalink | Comments (0)

NAI Postdoctoral Fellow Sean Raymond leads a team of authors from NAI's University of Colorado, Boulder, and University of Arizona Teams, and Virtual Planetary Laboratory and University of Washington Alumni Teams in a new publication in Astrobiology. They present analysis of water delivery and planetary habitability in 5 high-resolution simulations forming 15 terrestrial planets. Their results outline a new model for water delivery to terrestrial planets in dynamically calm systems, which may be very common in the Galaxy. [Source: NAI Newsletter]

Posted by Keith Cowing at 10:56 PM | Permalink | Comments (0)

New work from NAI NASA Ames Research Center Team members and their colleagues published recently in PNAS suggests that the cause for much of the extended red emission, or ERE, is due to closed-shell cationic polycyclic aromatic hydrocarbon, or PAH, dimers. Their work sheds light on the processes involved in carbonaceous dust evolution in the interstellar medium. [Source: NAI Newsletter]

Posted by Keith Cowing at 11:00 PM | Permalink | Comments (0)

Search for Habitable Planets Outside Earth's Solar System in Astrobiology

"Which planets outside of Earth's Solar System are most likely to be capable of supporting life is a question that will be the focus of both a NASA-sponsored workshop later this year and a special collection of papers in the Spring 2007 (Volume 7, Number 1) issue of Astrobiology, a peer-reviewed journal published by Mary Ann Liebert, Inc."

Posted by Keith Cowing at 1:48 PM | Permalink | Comments (0)

Special session at the 210th Meeting of the American Astronomical Society in Honolulu, Hawaii
Thursday May 31 (Morning) Convenors: Nader Haghighipour and Eric Gaidos (University of Hawaii NAI Lead Team)

Continue reading "Hot Earths: Formation, Detection and Structure" »

Posted by Keith Cowing at 8:29 PM | Permalink | Comments (0)

NAI's Marine Biological Laboratory and Carnegie Institution of Washington Teams are contributing authors on a new paper in Earth and Planetary Science Letters presenting a new model for the evolution of Proterozoic deep seawater composition based on rare earth elements. Their data suggest transitional, suboxic conditions in the deep ocean (vs. sulfidic), which likely limited nutrient concentrations in seawater and, consequently, may have constrained biological evolution. [Source: NAI Newsletter]

Posted by Keith Cowing at 8:25 PM | Permalink | Comments (0)

Special Session "Microbially mediated processes governing the redox cycling of metals" at the 2007 Goldschmidt Conference, Cologne (Germany) Session Organizers: Colleen Hansel, School of Engineering and Applied Sciences, Harvard University Andreas Kappler, Center for Applied Geoscience, University of Tübingen

Continue reading "Microbially mediated processes governing the redox cycling of metals" »

Posted by Keith Cowing at 8:33 PM | Permalink | Comments (0)

Speaker: Tim Raub (Yale University), Date/Time: Monday, February 26, 2007 11AM PST

Background: Using atmospheric chemical models of a Snowball Earth, scientists from NAI's Alumni Virtual Planetary Laboratory Team showed that, during long and severe glacial intervals, a weak hydrological cycle coupled with photochemical reactions involving water vapor would give rise to the sustained production of hydrogen peroxide. The peroxide, upon release from melting ice into the oceans and atmosphere at the end of the snowball event, could mediate global oxidation events.

Continue reading "NAI Director's Seminar "New and Emerging Perspectives on Late Precambrian 'Snowball Earth' Glaciation"" »

Posted by Keith Cowing at 1:19 AM | Permalink | Comments (0)

Using atmospheric chemical models of a Snowball Earth, scientists from NAI's Alumni Virtual Planetary Laboratory Team show that, during long and severe glacial intervals, a weak hydrological cycle coupled with photochemical reactions involving water vapor would give rise to the sustained production of hydrogen peroxide. The peroxide, upon release from melting ice into the oceans and atmosphere at the end of the snowball event, could mediate global oxidation events. Their results are published in the December 12th issue of PNAS. [Source: NAI Newsletter]

Production of hydrogen peroxide in the atmosphere of a Snowball Earth and the origin of oxygenic photosynthesis, PNAS

Continue reading "Snowball Earth and the Origin of Photosynthesis" »

Posted by Keith Cowing at 1:20 AM | Permalink | Comments (0)

Robert Hazen, from NAI's Carnegie Institution of Washington Team, published his 2005 Presidential Address to the Mineralogical Society of America in this month's American Mineralogist.

Continue reading "Mineral Surfaces and Life" »

Posted by Keith Cowing at 12:27 AM | Permalink | Comments (0)

The December 2006 issue of Geobiology is a collection of papers focusing on the history of Earth's biogeochemistry, from the earliest sedimentary rocks in Greenland to the late Proterozoic. The rise of atmospheric oxygen provides a thematic link.

Continue reading "Oxygen and Life in the Precambrian" »

Posted by Keith Cowing at 12:26 AM | Permalink | Comments (0)

NAI has approved funding for the development of a new, state-of-the-art facility capable of recreating past atmospheric and oceanic conditions, to be called VAL, the Variable Atmospheres Laboratory. Capable of simulating various combinations of oxygen, carbon dioxide, temperature, and hydrogen sulfide levels, this facility will be able to test new hypotheses for the cause of some of the Earth's major mass extinction events - such as the Permian and Triassic mass extinctions.

Continue reading "NAI Researchers to Recreate Conditions of the Early Earth" »

Posted by Keith Cowing at 12:23 AM | Permalink | Comments (0)

Philosophical Transactions of the Royal Society (B). Organised and edited by Charles Cockell, Sydney Leach and Ian Smith Published August 2006

Continue reading "Conditions for the Emergence of Life on the Early Earth: Special Issue Special Issue" »

Posted by Keith Cowing at 9:50 PM | Permalink | Comments (0)

Speakers: Sean Raymond (University of Colorado) and Avi Mandell (Goddard Space Flight Center) Date/Time: Monday, November 27, 2006 11AM PST

Continue reading "NAI Director's Seminar 11/27: Formation of Habitable Planetary Systems: Are We Normal?" »

Posted by Keith Cowing at 9:49 PM | Permalink | Comments (0)

Towards the end of our summer expedition while flying back to Eureka from our camp on Axel Heiberg, I spotted a lake with what appeared to be green ice on it.

Continue reading "Green ice, Ravens, Ice Caves and the Movie ‘Contact’" »

Posted by Dale Andersen at 6:58 PM | Permalink | Comments (0)

Andrey Bekker of NAI's Carnegie Institution of Washington Team and his colleagues have an article in press for Precambrian Research which details the carbon isotope record for the carbonate platform in the Great Lakes area.

Continue reading "Carbon Isotope Record from ~2.2 Ga Rocks in the Great Lakes Area" »

Posted by Keith Cowing at 10:54 AM | Permalink | Comments (0)