Responsibilities and Interests:

Soil microbiological analysis; characterization of microbial populations and communities in the soil and rhizosphere; application of molecular biology methods to soil microbial ecology.

Research Interests: Comparative microbial ecology of terrestrial systems; microorganisms involved in nitrogen cycling and retention; microbial ecology-based approaches to reducing nutrient losses from agriculture and forestry; DNA fingerprinting to track composition of microbial communities in soils and rhizospheres.

Education:

• Ph.D. Crop & Soil Sciences, Michigan State University, 1996
• M.A. Urban & Regional Planning, Environmental Sector, Univ. of Iowa, 1988
• M.S. Food Science & Technology, Univ. of Nebraska, 1978
• B.A. Microbiology, Univ. of Nebraska, 1974

SOIL MICROBIAL ECOLOGY LABORATORY

A single gram of agricultural topsoil may contain at least one billion bacteria, a hundred thousand fungi, and thousands of protozoans and other microscopic organisms! Our ability to study such incredibly diverse microbial assemblages is hampered by the fact that most of these microorganisms will not grow under laboratory conditions. To get around this problem, M.A. Bruns’s soil microbial ecology lab employs DNA fingerprinting of bacterial and eukaryotic communities to learn more about the key microorganisms involved in soil nutrient cycling and other important environmental processes. Basic steps involved in DNA fingerprinting are 1) extracting microbial DNA from soil; 2) polymerase chain reaction (PCR) amplification of ribosomal RNA genes; 3) separation of the PCR products by gel electrophoresis; and 4) computer-assisted analysis of the “fingerprints,” or DNA band patterns produced in the gels. If we want to know more about the microbial populations that produce specific bands, we can cut these bands out of the gels, obtain their DNA sequence(s), and use the sequences for preliminary identification. We are interested in learning how soil microbial communities change over time when they are subjected to different environmental conditions and management treatments. We want to learn how to work with (not against!) the beneficial microorganisms that cleanse and improve our environment.

Research Areas and Relevant Publications

Biological Fe(II) oxidation in soil formation and development

• Buss HL, MA Bruns, MJ Schultz, J Moore, CF Mathur, and SL Brantley. 2006. The coupling of biological iron cycling and mineral weathering during saprolite formation, Luquillo Mountains, Puerto Rico. Geobiology 3: 247–260.

Biological treatment of acidic coal mine drainage and restoration of AMD “kill zones”

• Senko, J.M., G. Zhang, G.T. McDonough, M.A. Bruns, and W.D. Burgos. 2009. Metal reduction at low pH by a Desulfosporosinus species: implications for the biological treatment of acidic mine drainage. Geomicrobiology J., 26:71–82.
• Senko, J.M., P. Wanjugi, M. Lucas, M.A. Bruns, W.D. Burgos. 2008. Characterization of Fe(II) oxidizing bacterial activities and communities at two acidic Appalachian coalmine drainage-impacted sites. ISME J. 2:1134–1145.
• Machulla G, MA Bruns, and KM Scow. 2005. Microbial properties of mine spoil materials in initial stages of soil development. Soil Science Society of America Journal 69:1069–1077.

Impacts of mulching on soil organisms and biogeochemical processes

• Byrne, L.B., M.A. Bruns, and K.C. Kim. 2008. Ecosystem properties of urban land covers at the aboveground-belowground interface. Ecosystems 11:1065–1077.

Biohydrogen production from wastes

• Luo, Y.H., H. Zhang, M. Salerno, B.E. Logan, and M.A. Bruns. 2008. Organic loading rates affect composition of soil-derived bacterial communities during continuous, fermentative biohydrogen production. Internatl J Hydrogen Energy 33:6566–6576.
• Zhang H, MA Bruns, and BE Logan. 2006. Biological hydrogen production by Clostridium acetobutylicum in an unsaturated flow reactor. Water Research 40:728–734.
• Oh S-E, P Iyer, MA Bruns, and BE Logan. 2004. Biological hydrogen production using a membrane bioreactor. Biotechnol Bioengineering 87:119–127.

Biotreatment of animal wastes

• Kim, J.R., J. Dec, M.A. Bruns, and B.E. Logan. 2008. Removal of odors from swine wastewater by using microbial fuel cells. Appl. Environ. Microbiol. 74:2540–2543.
• Wheeler, EF, PA Topper, RE Graves, MA Bruns, and C Wysocki. 2007. Odor reduction performance of constructed wetland treating diluted swine manure. Applied Engineering in Agriculture 23(5):621–630.
• Castillo-Gonzalez HA and MA Bruns. 2005. Dissimilatory iron reduction and odor indicator abatement by biofilm communities in swine manure microcosms. Appl. Environ. Microbiol. 71:4972–4978.

Microbially mediated sulfur and metal transformations in soils

• Martínez, CE, CE Yáñez, SJ Yoon, and MA Bruns. 2007. Biogeochemistry of metalliferous peats : Sulfur speciation and depth distributions of dsrAB genes and Cd, Fe, Mn, S, Zn in Soil Cores. Environ Sci Technol. 41:5323–5329.

Microbial community analysis

• Turich, C, KH Freeman, MA Bruns, M Conte, AD Jones, and SG Wakeham. 2007. Lipids of marine Archaea: Patterns and provenance in the water-column and sediments. Geochim Cosmochim Acta 71:3272–3291.
• Zhang, H, Logan BE, Regan JM, Achenbach LA, Bruns MA. 2005. Molecular assessment of inoculated and indigenous bacteria in biofilms from a pilot-scale perchlorate-reducing bioreactor. Microbial Ecology 49:388–398.

Current students

• Maina Martir Torres, Ph.D. candidate in Soil Science with dual major in Biogeochemistry
  Research: Diversity of ammonia-oxidizing prokaryotes in soils under urban management
• Morgan Minyard, Ph.D. candidate in Soil Science with dual major in Biogeochemistry
  Research: Role of iron-oxidizing bacteria in saprolite and soil formation
• Claudia Rojas, first-year Ph.D. student in Soil Science with dual major in Biogeochemistry
  Research: Biological restoration of land affected by acid mine drainage

Where Are They Now?

M.S. Graduates

• Pauline Wanjugi, M.S. Soil Science (2008), Integrated Biosciences Ph.D. program, University of South Florida, Tampa, FL
• Mary Kay Lupton, M.S. Soil Science (2008), Research Technician, Soil Characterization Lab, Penn State

Ph.D. Graduates

• Yonghua Luo, Ph.D. Soil Science (2007), Postdoctoral Researcher, USDOE National Renewable Energy Laboratory, Golden, Colorado
• Loren Byrne, Ph.D. Ecology (2006), Assistant Professor of Biology, Roger Williams University, Bristol, RI
• Jody Gibson, Ph.D. Soil Science (2005), TGE Resources, Inc., Houston, TX, now in Bakersfield, CA
• Hugo Castillo, Ph.D. Ecology (2005), Facultad de Zootecnia, Universidad Autonoma de Chihuahua, Mexico

Postdoctoral Scientists

• Emily Fleming, Postdoctoral Associate (2008), Bigelow Laboratory for Ocean Sciences, West Boothbay Harbor, Maine
• Prabha Iyer, Postdoctoral Associate (2004), J. Craig Venter Institute, Rockville, MD

Undergraduate Research “Alumni”

• Chantel Evans-Dixon, MURE (2007–2008), rising senior in Food Science at Penn State
• Julie Bowdle (2007), received B.S. in Soil Science and entered graduate program in Engineering, UC Berkeley
• Wayne Lehman (2004–2005), received B.S. in Ecology and M.S. in Environmental Pollution Control from Penn State and now works for Schuylkill Conservation District
• Amber Lockawich (2005), received B.S. in AgroEcology
• Dan Thetford, Discovery Grant (2005), received Soil Science B.S. from Penn State
• Margaret-Hannah Emerick, WISER (2005)
• Jen Lundy (2005–2006), entered Medical Technology program after graduating
• Erica Petrie (2004), Ag & Biological Engineering Honors Program
• Carrie Anderson (2004), entered Medical Technology program after graduating
• Matt Schultz, BRIE Summer Fellow (2004)
• Sandra Campos, BRIE Summer Fellow (2004)
• Krystal Hamlett, BRIE Summer Fellow (2003), graduated from Lincoln University in 2006
• Summer Holmes, MURE (2003), Mount Sinai Medical School, New York City
• Taco Williams, BRIE Summer Fellow (2002)
• Jennifer Quinlan (2002)