The Nüsslein Group
Microbial Ecology at the University of Massachusetts Amherst
Although several studies have focused on the role of microorganisms on acid mine drainage (AMD) genesis, my research goal is to determine the impact of sulfate-reducing bacteria (SRB) to reverse the oxidative processes that produce AMD at Davis mine in Rowe, Massachusetts.
Evidences for sulfate reduction include both field observations and molecular results. For example, the low oxidation-reduction potential (ORP) along with near-neutral pH and decreasing sulfate concentrations suggest that SRB may be active in the vicinity of the bedrock tailings along the bottom of the acidic drainage plume. Also, the presence of black precipitates and a pronounced odor of H2S observed in sampled ground water indicate that sulfate reduction is occurring [2], while studies based on 16S rRNA gene-based analysis reveal SRB near the monitoring wells along the periphery of the AMD effluent [1]. It has recently been accepted that SRB are present and active in low pH environments [3].
While we have begun to describe the microbial community, the microbial activity will be the focus and ascertained through the application of a combination of molecular techniques, such as fluorescent in situ hybridization (FISH) and the amplification of functional genes, as well as geochemical techniques using sulfur isotopes to obtain sulfate reduction rates. By determining the rate of sulfate reduction and the abundance and diversity of SRB at Davis mine, we can provide estimates of their likely importance in other global settings as well as application in industrial waste streams.
References:
[1] Ergas SJ, Harrison J, Bloom J, Forloney K, Ahlfeld DP, Nüsslein K, Yuretich RF. 2005. Natural attenuation of acid mine drainage by acidophilic and acidotolerant fe(III)- and sulfate-reducing bacteria. In C. Clark II and A. Lindner (eds.), remediation of hazardous waste in the subsurface: bridging flask and field studies. Washington DC.: American Chemical Society Symposium Series, No. 940.
[2] Fortin D, Beveridge TJ. 1997. Microbial sulfate-reduction within mine tailings: Formation of diagenetic Fe-sulfides. Geomicrobiology Journal 14:1-21.
[3] Koschorreck M. 2008. Microbial sulphate reduction at low pH. FEMS Microbiology Ecology:1-14.
Ford Foundation Fellowship (2007-2010)
CEA-CREST Bridges Doctoral Fellowship (2004-2007)
M.S. Geobiology, CSULA (2003)
Agouron International Geobiology Program (2002)
A.B.A. Biochemistry and Environmental Science, Occidental College (2001)
International Society for Microbial Ecology (ISME)
Becerra, C.A., E. L. López-Luna, S.J. Ergas, and K. Nüsslein (2009). Microcosm-based Study of the Attenuation of an Acid Mine Drainage-Impacted Site Through Biological Sulfate and Iron Reduction. Geomicrobiology Journal 26: 9-20.
Becerra, C.A. and K. Nüsslein, "Sulfate-reducing bacteria attenuate acid mine drainage", International Society of Microbial Ecology, Seattle, WA, August 2010.
Becerra, C.A. and K. Nüsslein, "Bacterial sulfate reduction at an acid mine drainage site", 109th Annual General Metting of the American Society of Microbiology, Philadelphia, PA, May 2009.
Becerra, C.A. and K. Nüsslein, “Microbial sulfate reduction in the attenuation of acid mine drainage,” 108th Annual General Meeting of the American Society of Microbiology, Boston, MA, June 2008.
Becerra, C.A. and K. Nüsslein, “Attenuation of acid mine drainage by microbes,” New England Microbial Physiology, Ecology, and Taxonomy, June 2007
Becerra, C.A., A. Sengupta, D.A. Ahlfeld, K. Nüsslein, “Natural attenuation of acid mine drainage by microbiological and hydrological processes at Davis Mine, Rowe, MA,” MA Water Resources Research Center, University of Massachusetts, Amherst, April 2007. (platform presentation)
Becerra, C.A. and K. Nüsslein, “Visualization of sulfate-reducing bacteria in microcosms of an acid mine drainage site,” SACNAS Annual National Conference, Tampa, Florida, October 2006.
Becerra, C.A. and K. Nüsslein, “Flask microcosm studies of microbial sulfate reduction contributing to the natural attenuation of acid mine drainage at Davis mine, Rowe, Massachusetts,” 106th Annual General Meeting of the American Society of Microbiology, Orlando, Florida, May 2006.
Becerra, C.A., E. Lopez-Luna, S. Ergas, K. Nüsslein, “Natural attenuation of acid mine drainage from microcosms of Davis mine in Rowe, Massachusetts,” The Annual International Conference on Soils, Sediments, and Water, University of Massachusetts, Amherst, October 2005.
Lopez-Luna, E., C.A. Becerra, K. Nüsslein, S. Ergas, “In situ and laboratory studies on the role of natural attenuation of acid mine drainage,” Massachusetts Water Resources Research Center Annual Conference, University of Massachusetts, Amherst, October 2005.
Becerra, C.A., E. Lopez-Luna, S. Ergas, and K. Nüsslein, “Natural attenuation of acid mine drainage simulated in microcosms of Davis mine, Rowe, Massachusetts,” SACNAS (Society for Advancement of Chicanos and Native Americans in Science) Annual National Conference, Denver, Colorado, September 2005. (platform presentation)
Mentoring has been and continues to be a rewarding activity for me. Currently I am mentoring three students who have participated in research activities on the Davis mine project for over a year. I have enjoyed teaching them and have been thrilled to witness them grow with excitement and independence.
Brendan has constructed microcosms to elucidate the production of reduced iron by the reduction of biogenic sulfide.
Albert and Frances have been tediously working on obtaining acidophilic/acidotolerant sulfate-reducing bacteria from Davis mine.
Thank you also to past undergraduate students and high school teachers who have participated in research during the summer and the academic year: Saheel Patel, Lotfi Bassa, Thach Chu, Sharon McDonald, and Denise Fiedler.
