9714302 Luther PROJECT SUMMARY Organisms that thrive in high temperature (hyperthermophiles) ecosystems such as at terrestrial and deep-sea hydrothermal vents, have challenged our understanding of the physical and biochemical constraints on the upper temperature limits for life and stimulated new theories on how life originated (e.g. Baross and Hoffman, 1985; Pace, 1991). These hyperthermophiles are the most closely related to the universal ancestor for all life (from small subunit rRNA and gene duplication data) which supports the theory that life arose in highly reduced, high temperature environments such as those encountered at hydrothermal vent systems. Recently scientists proposed a mechanism for the synthesis of the first molecules for life in which pyrite can be synthesized abiotically with hydrogen as a product, laying the framework for the evolution of the first metabolic cycles. The central hypothesis of this study maintains that the abiotic synthesis of pyrite provides the essential properties for sequestering the energy sources for chemoautotrophic metabolism of the deepest lineages of life. Drs. Luther and Reysenbach believe that under an extreme chemical and physical environment microorganisms can utilize the resources provided on the pyrite surfaces for sustained metabolism. They also believe that these organisms will closely represent early life forms that may have occupied similar extreme habitats. Furthermore, since molecular phylogenetic evidence exists that the deepest of these thermophilic lineages inhabit iron and sulfidic-rich environments at deep-sea hydrothermal vents, they are well-positioned to test these assertions. The objective of this research are: 1. To establish whether pyrite and the associated adsorbed trace metals and simple inorganic molecules will mediate the microbial community structure in high temperature aquatic environments. 2. To determine whether pyrite synthesi s can be predicted, through the simultaneous measurement of FeS and hydrogen sulfide. This project clearly addresses most of the primary mandates of the LExEn research program. In this interdisciplinary study these collaborators will integrate molecular genetic approaches with in situ geochemistry to study the diversity, ecology, and evolutionary history of the microorganisms thriving in extreme habitats where intense redox and temperature gradients exist. This project is cooperatively supported by the Divisions of Ocean Science and Chemistry, and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate

Agency
National Science Foundation (NSF)
Institute
Division of Ocean Sciences (OCE)
Type
Standard Grant (Standard)
Application #
9714302
Program Officer
Elizabeth Rom
Project Start
Project End
Budget Start
1998-01-01
Budget End
2001-12-31
Support Year
Fiscal Year
1997
Total Cost
$471,324
Indirect Cost
Name
University of Delaware
Department
Type
DUNS #
City
Newark
State
DE
Country
United States
Zip Code
19716