2000 Annual Science Report
Pennsylvania State University Reporting | JUL 1999 – JUN 2000
Paleomicrobiology and the Evolution of Metabolic Pathways in the Archaean Environment.
The project has two parts. First, ancient microfossils preserved in cherts are being studied with an ion microprobe allowing the analysis of the carbon isotopic composition of individual microfossils. Second, the process of carbon isotopic fractionation is being studied in a diverse set of microorganisms. Collectively, the results will constrain the carbon fixation biochemistry of ancient microorganisms.
The first part of this project has made great progress during the reporting period. For the first time, the multicollection mode of the ion microprobe was used to determine the carbon isotopic composition of about 15 different microfossils specimens. Previously, we had only been able to use the monocollection mode of the ion microprobe for this task. The multicollection mode runs faster and has better precision. During the reporting period, these ion microprobe analyses formed the center of a paper written to Geology. The paper has been accepted for publication and is expected to appear in print soon. We had hoped to have this paper published sooner, but it was delayed by the necessity of Dr. House to finish his Ph.D. dissertation.
The second aspect of the project has been the study of carbon isotopic fractionation in a diverse set of microorganisms. This work is proceeding well. To better understand our original results, we have further studied the carbon isotopic fractionation of Methanococcus species. We expect to submit a paper soon. This project will help in the development of life detection strategies, a principle goal of Astrobiology.
PROJECT MEMBERS:T. Mark Harrison
RELATED OBJECTIVES:Objective 4.0
Expand and interpret the genomic database of a select group of key microorganisms in order to reveal the history and dynamics of evolution.
Describe the sequences of causes and effects associated with the development of Earth's early biosphere and the global environment.
Define how ecophysiological processes structure microbial communities, influence their adaptation and evolution, and affect their detection on other planets.
Identify the environmental limits for life by examining biological adaptations to extremes in environmental conditions.