Margaret Anne Hinkle

Education

• Ph.D. (September 2010 – May 2015) in Earth & Planetary Sciences, Washington University in St. Louis. Dissertation: “Ion interactions at the mineral-water interface during biogeochemical iron and manganese cycling.” Advisor: Prof. Jeffrey G. Catalano
• A.M. (September 2010 – May 2012) in Earth & Planetary Sciences, Washington University in St. Louis. Advisor: Prof. Jeffrey G. Catalano
• B.S. (September 2005 – May 2009) in Chemistry (academic minor: Anthropology), Sewanee: The University of the South, cum laude. Research Advisor: Prof. Robert E. Bachman, Advisor: Prof. John H. Shibata

Research

I study how trace metals common in natural systems (many of which are micronutrients and contaminants) and mineral structures are affected during iron and manganese biogeochemical cycling, with the goal of understanding how biogeochemical processes at the mineral-water interface affect the compositions of natural waters in present day and geologic systems. I study both abiotic and biotic factors contributing to changes in mineral structures and trace metal speciation and uptake. My research combines my interests in inorganic chemistry, aqueous geochemistry, and biomineralization. I am currently studying fungal manganese oxides with my postdoctoral fellowship -- fungi are intimately linked to several geologic and environmental processes, such as element cycling, mineral formation and dissolution, rock weathering, soil formation, and the mobility of trace metals. I use wet chemistry techniques and bulk characterization methods, such as X-ray diffraction, Fourier transform infrared spectroscopy, and synchrotron-based X-ray absorption spectroscopy, in my research.

Teaching

• EEG 101 General Geology
• EEG 102 Sustainable Earth
• EEG 105 Earth Lab: Dam it?!: Environmental Exploration of Dams
• EEG 150 Water Resources
• EEG 231 Environmental Field Methods
• EEG 240 Hydrology
• EEG 311 Earth and Environmental Geochemistry

Selected Publications

• Hinkle M.A.G., Ziegler B., Culbertson H., Goldmann C., Croy M.E., Willis N., Ling E., Reinhart B., Lyon E.C. (2024) “Manganese exposure from spring and well waters in the Shenandoah Valley: interplay of aquifer lithology, soil composition, and redox conditions.” Environmental Geochemistry and Health 46, 203, 1-27.
  
  
• Hinkle M.A.G., Post J.E., Peralta J., Santelli C.M. (2023). “Impacts of sulfonic acids on fungal manganese oxide production.” Geochimica et Cosmochimica Acta 341, 164–182.
  
  
• Rosenfeld, C.E., Sabuda, M. C., Hinkle, M.A.G., James, B.R., Santelli, C.M. (2020) “A fungal-mediated cryptic selenium cycle linked to manganese biogeochemistry.” Environ. Sci. Technol. 2020, 54, 6 3570-3580.
  
  
• Hinkle M.A.G., Becker K.G., Catalano J.G. (2017) “Impact of Mn(II)-manganese oxide reactions on Ni and Zn speciation.” Environmental Science & Technology 51, 3187-3196.
  
  
• Hinkle M.A.G., Flynn E.D., Catalano J.G. (2016) “Structural response of phyllomanganates to wet aging and Mn(II).” Geochimica et Cosmochimica Acta 192, 220-234.
  
  
• Arvidson R.E., Squyres S.W., Morris R.V., Knoll A.H., Gellert R. Clark B.C., Catalano J.G., Jolliff B.L., McLennan S.M., Herkenhoff K.E., VanBommel S., Mittlefehldt D.W., Grotzinger J.P., Guinness E.A., Johnson J.R., Bell III J.F., Farrand W.H., Stein N., Fox V.K., Golombek M.P., Hinkle M.A.G., Calvin W.M., Desouza Jr. P.A. (2016) “High concentrations of manganese and sulfur in deposits on Murray Ridge, Endeavour Crater, Mars.” American Mineralogist 101, 1389-1405.
  
  
• Hinkle M.A.G. and Catalano J.G. (2015) “Effect of phosphate and sulfate on Ni repartitioning during Fe(II)-catalyzed Fe(III) oxide mineral recrystallization.” Geochimica et Cosmochimica Acta 165, 62-74.
  
  
• Hinkle M.A.G., Wang Z., Giammar D.E., Catalano J.G. (2015) “Interaction of Fe(II) with phosphate and sulfate on iron oxide surfaces.” Geochimica et Cosmochimica Acta 158, 130-146.