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2009 Annual Science Report

Arizona State University Reporting  |  JUL 2008 – AUG 2009

Stoichiometry of Life, Task 2a: Field Studies - Yellowstone National Park

Project Summary

We are investigating how the element requirements of microbes are affected by element availability in their environment in Yellowstone National Park, where there are extreme variations in the abundances of bioessential elements in addition to extremes of temperature and pH. In Year 1 we organized a multi-disciplinary field expedition to collect samples and conduct experiments. Analyses of these samples is now underway.

4 Institutions
3 Teams
8 Publications
1 Field Site
Field Sites

Project Progress

A multi-disciplinary group of ~ 30 people spent two weeks working on stoichiometry of life projects in the hydrothermal ecosystems of Yellowstone National Park (20 July – 7 August, including travel time). Our goals were to 1) collect nested samples of water, gas, sediment and biofilms from locations that represent much of the diversity of geochemical habitats in Yellowstone hot springs (Figure 1), 2) conduct a study of the nitrogen cycle in hot spring ecosystems that can be tied to gene expression and metal abundances, and 3) collect samples for specific gene searches related to the carbon, nitrogen and iron cycles. The first project, led by co-I Everett Shock and postdoc Jeff Havig, included sampling for major and trace elements, and was coordinated with samples for molecular investigations of genes involved in metal uptake, metal cycling, genes for metalloenzymes, and specific targets in the nitrogen cycle. The second project, led by collaborator Hilairy Hartnett and graduate student Steven Romaniello, involved several day-long incubation experiments to follow the various steps of the complex — but mostly unexplored — nitrogen cycles that prevail in hot spring ecosystems. The third project was lead by co-I D’Arcy Meyer-Dombard (UIUC), and involved coordinated sampling of waters and biofilms to be subjected to a variety of molecular methods to search for specific genes.

Lab results based on samples collected in the field campaign were begun at the end of Year 1. Analyses for major and trace element analysis are underway, as are DNA extraction, gas analysis and N-isotope studies. Gas samples show that dissolved hydrogen can be quantified in diverse hot spring settings, and that it can increase in some hot spring outflow channels for reasons that are likely to be microbial but that are presently not understood (these analyses are being done in collaboration with Tori Hoehler at NASA Ames). Early results on the nitrogen cycle samples shows evidence for denitrification. Nutrient measurements are complete and work has begun on elemental compositions of biological material.

In a related effort, collaborator Hongyu Yu along with graduate students Jonathan Oiler and Xiaotun Qiu are working to develop sensors suitable for in situ measurements in the hot springs at Yellowstone. Oiler is working on flexible microfluidic sensor matrix, which will include the sensing functions of shear stress, flow, temperature, conductivity, oxygen concentration. Qiu is working on ZnO based micro resonant devices for variety chemical and physical parameter sensing. He has built a testing platform for the sensors and developed the functions of UV sensing, Ethanol sensing, and Acetone sensing. He is now working on pH sensing.

Figure 1. Analyzing hydrothermal water samples at Yellowstone National Park.ASU Ph.D. student Michelle Knowlton analyzes hydrothermal water samples in Sentinel Meadow, Yellowstone National Park. (Photo credit: A. D. Anbar)