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D'Arcy Meyer-Dombard

Research Interests

I approach geomicrobiology from an ecological perspective, using geochemistry, molecular, and microbiology to build ecological models of hydrothermal systems. I’m currently focusing on geomicrobial processes at interfaces between mildly reducing hydrothermal fluids and oxidizing surface sediments and waters in terrestrial systems (Yellowstone National Park) and shallow marine systems (Italy, Papua New Guinea). I’m interested in using molecular (genomic), geochemical, and isotopic parameters to identify the metabolic strategies, nutrient/energy requirements, and geochemical signatures (lipid biomarkers) of thermophilic and chemolithotrophic Bacteria and Archaea. My focus over the next several years will be carbon, nitrogen, and energy cycling in hydrothermal sediment and biofilm communities.

In collaboration with researchers at Arizona State University and UC Merced, I am also pursuing a new initiative to assess correlations between metabolic genes and predicted energy sources. This pilot project, the first of its kind, follows a thermal/chemical gradient across the chemotrophic-phototrophic interface of a hotspring outflow channel, and will integrate metagenomics, geochemistry, and thermodynamic predictions of energy availability. Results will include functional profiles and phylogenetic analysis of orthologous environmental gene tags.

In addition, I am continuing work detailing ecosystem response to elevated arsenic concentrations in shallow submarine hydrothermal systems in PNG (see http://www.biocomplexity.usf.edu/). This work investigates potential microbial influences on the adsorbtion of arsenic to Fe(III) oxyhydroxide precipitates surrounding the vents. A variety of culturing and molecular biological techniques are being used to identify microbe-mineral interactions in this system. These efforts may elucidate means of remediation for arsenic contamination in groundwater, a world-wide environmental concern.

Selected Relevant Publications

Meyer-Dombard, D.R., Shock, E.L., Amend, J.P. (2005), Archaeal and Bacterial Communities in Geochemically Diverse Hot Springs of Yellowstone National Park, USA. Geobiology, 3, 211-227.

Shock, E.L. Holland, M. Meyer-Dombard, D. and Amend J.P. (2005) Geochemical sources of energy for microbial metabolism in hydrothermal ecosystems: Obsidian Pool, Yellowstone National Park, USA. Geothermal Biology and Geochemistry in Yellowstone National Park. (W. Inskeep, T. McDermott, eds.), Thermal Biology Institute, Montana State University (pp. 95-112).

Amend, J.P., Rogers, K.L., and Meyer-Dombard, D.R., (2004), Microbially mediated sulfur-redox: Energetics in marine hydrothermal vent systems. IN: Sulfur Biogeochemistry-Past and Present.GSA Special Paper 379 (Eds., Amend, J.P, Edwards, K.J., and Lyons, T.W.),p.17-34.

Amend, J.P., Meyer-Dombard, D.R., Sheth, S.N., Zolotova, N., and Amend, A.C. (2003), Palaeococcus helgesonii, sp. nov., a facultatively anaerobic, hyperthermophilic Archaeon from a geothermal well on Vulcano Island, Italy.  Archives of Microbiology, 179, 394-401.