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2012 Annual Science Report

Pennsylvania State University Reporting  |  SEP 2011 – AUG 2012

Executive Summary

Through an integration of education and research, the Penn State Astrobiology Research Center (PSARC) is dedicated to developing the conceptual, analytical, and technical tools to detect life, extant or extinct. This past year has been a great one for PSARC researchers. Each of our four major research projects had splendid results, novel directions, and new important papers.

Developing New Biosignatures

The Developing New Biosignatures project is aimed at creating innovative approaches for the analyses of cells and other organic material, finding ways in which metal abundances and isotope systems reflect life, and developing creative approaches for using environmental DNA to study present and past life. This past year saw significant progress on several areas of research for this project. In particular, The detection of diverse microscopic fossils preserved in gypsum is of significance for the potential discovery of fossils in Mars sulfates and should influence the selection of sites for Mars surface sample collection. This discovery, coupled with that of Schopf and his colleagues of a previously unreported Precambrian sulfur-dependent ecosystem — sulfuretums essentially identical to that living today and now known from their work to be preserved in 1,800- and 2,300-Ma-old geological units — hold promise for the discovery of ancient and perhaps even extant life on Mars. Our work on DNA as a biosignature also say significant progress with papers on DNA preservation in Pleistocene-aged fossils (e.g., Letts and Shapiro, 2012), as well as progress on new methods for amplifying trace amounts of DNA. We also reported the use of Scytonemin as an interesting biomarker showing cyanobacterial populations.

Biosignatures in Relevant Microbial Ecosystems

The Biosignatures in Relevant Microbial Ecosystems project explores the isotope ratios, gene sequences, minerals, organic molecules, and other signatures of life in modern environments that have important similarities with early earth conditions, or with life that may be present elsewhere in the solar system and beyond. Many of these environments are “extreme” by human standards and/or have conditions that are at the limit for microbial life on Earth. During the last year, the team made great progress with work on the Dead Sea, the Chesapeake Bay impact structure, Eel River Basin methane seeps, Greenland glacier ice, and redox-stratified precambrian ocean analog sites.

Biosignatures in Ancient Rocks

The Biosignatures in Ancient Rocks group investigates the co-evolution of life and environment on early Earth using a combination of geological field work, geochemical analysis, genomics, and numerical simulation. Our team made great progress this last year with a high number of papers submitted to peer-reviewed journals. Also, during the reporting period, the team published a manuscript reporting evidence for a large depletion of phosphorous from the surface of a Cambrian paleosol, as well as a three volume book of the extensive results of the NAI co-funded FAR-DEEP continental drilling project that investigated the record of Earth’s oxygenation during the Palaeoproterozoic.

Biosignatures in Extraterrestrial Settings

The Biosignatures in Extraterrestrial Settings explores indicators of life outside of Earth, both within the Solar System and on extrasolar planets. The work includes studies of the chemistry and composition of the Solar System, and the past history of conceivable sites for life in the Solar System. We also look for habitable planets outside the Solar System; work on developing new techniques to find and observe potentially habitable planets; and model the dynamics, evolution and current status of a variety of extrasolar planets. This past year saw the “habitable zone planet finder near-infrared spectrograph” funded by a National Science Foundation Major Research Instrumentation grant, leveraging off the pathfinder instrument which was funded in part by NAI. Also of particular interest, Graduate student Matthew Route published results of a radio search for sub-stellar companions to nearby stars, and graduate student Sara Gettel published results of the search for exoplanets around K2-giant stars. This past year also saw the continuation of and initiation of a high number of collaborations and projects related to various topics including impact panspermia, exoplanet abundance, and the prospects for mid-infrared detection of habitable worlds.