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
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.
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.
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).
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., Amend, J.P., Osburn, G.R., Fischer, T.P., (2010), Quantifying Inorganic Sources of Geochemical Energy in Hydrothermal Ecosystems, Yellowstone National Park, USA, Geochimica et Cosmochimica Acta, 74:4005-4043.
Meyer-Dombard, D.R., M.R. Osburn, R. Price, T. Pichler, J.P. Amend. Prokaryotic populations in heated, arsenic-rich sediments of a shallow-sea hydrothermal system, Ambitle Island, Papua New Guinea. (in press, Geobiology Journal).
Jeff R. Havig, Jason Raymond, J., D'Arcy R. Meyer-Dombard, Natalya Zolotova, and Everett L. Shock. 2011. Merging Isotopes and Community Genomics in a Siliceous Sinter-Depositing Hot Spring. (in press, 116, G01005, doi:10.1029/2010JG001415, JGR Biogeosciences)
Meyer-Dombard, D.R., Swingley, W., Raymond, J., Havig, J., Shock, E.L., Summons, R.E. Hydrothermal Ecotones and Silica-Rich Biofilm Communities in the Lower Geyser Basin, Yellowstone National Park. (in press, Environmental Microbiology)
Meyer-Dombard DR, Shock EL, Amend JP. Effects of Trace Element Concentrations on Culturing Thermophiles. (accepted by Extremophiles).
Amend JP, Burcea L, Meyer-Dombard DR. Microbial diversity in alkaline hot springs of Ambitle Island, Papua New Guinea. (accepted by Extremophiles).
Manuscripts in Preparation for 2011 Submission:
Swingley, W. D., Meyer-Dombard, D. R., Alsop, E.B., Falenski, H.D., Havig, J. R.,Shock, E.L., and Raymond, J. Coordinating environmental genomics and geochemistry reveals metabolic transitions in a hot spring ecosystem. (submitted to PLoS ONE).
Meyer-Dombard DR, Osburn MR, Amend JP. Microbial diversity in biofilms deposited at an arsenic-rich shallow-sea hydrothermal vent (in preparation for special issue on arsenic in hydrothermal systems in Chemical Geology).
Amend JP, Meyer-Dombard DR, Schrenk MO. Variations in Archaeal and Bacterial Communities among Shallow-sea, Deep-sea, and Continental Hydrothermal Ecosystems, (in preparation for FEMS Microbiology Reviews).
Loiacono S, Meyer-Dombard DR, Shock EL. Expression of NifH and AmoA in Terrestrial Hydrothermal Systems. (in preparation for FEMS Microbiology Ecology)
Meyer-Dombard, D.R., Burton M. Diversity and Abundance of Key Nitrogen Cycling Genes in Alkaline Hydrothermal Features of Yellowstone National Park. (in preparation for Applied and Environmental Microbiology).