Sasha Wagner

Assistant Professor, Earth and Environmental Sciences

Our research focuses on the biogeochemistry of dissolved organic matter – a complex mixture of organic molecules deriving from fresh biomass, detritus, charred residues, and anthropogenic sources. Since dissolved organic matter is mobilized by water and is comprised of 50% carbon by mass, it plays an integral role in connecting terrestrial and oceanic carbon reservoirs and in regulating ecosystem structure and function. We specialize in the study of black carbon, the thermogenic fraction of organic matter that has a condensed aromatic molecular structure, is biologically inert, and persists in the environment for millennia. Our research program combines different geochemical techniques to constrain the role of dissolved organic matter and black carbon in a modern Earth system that is altered by anthropogenic activity and continued climate change.

If you are interested in joining our lab or learning more about the research we do, please visit our lab website or contact me at the email listed below.


PhD in Environmental Chemistry, Florida International University, 2015

BS in Biochemistry, University of Delaware, 2009

Research Focus
  • organic geochemistry
  • biogeochemistry
  • aquatic carbon cycling
  • dissolved organic matter
  • black carbon
Select Works
  • Coppola, A.I., Wagner, S., Lennartz, S.T., Seidel, M., Ward, N., Dittmar, T., Santin, C., Jones, M. (2022) The black carbon cycle and its role in the Earth system. Nature Reviews Earth and Environment
  • Barton, R., Wagner, S. (2022) Measuring dissolved black carbon in water via aqueous, inorganic, high-performance liquid chromatography of benzenepolycarboxylic acid (BPCA) molecular markers. PLoS ONE 17, e0268059.
  • Holt, A., Kellerman, A., Li, W., Stubbins, A., Wagner, S., McKenna, A., Fellman, J., Hood, E., Spencer, R.G.M. (2021) Assessing the role of photochemistry in driving the composition of dissolved organic matter in glacier runoff. Journal of Geophysical Research: Biogeosciences 126, e2021JG006516.
  • Goranov, A.I., Schaller, M. F., Long, J.A., Podgorski, D.C., Wagner, S. (2021) Characterization of asphaltenes and petroleum using benzenepolycarboxylic acids and compound-specific stable carbon isotopes. Energy and Fuels
  • Bauters, M., Drake, T., Wagner, S., Baumgartner, S., Makelele, I., Bode, S., Verheyen, K., Verbeeck, H., Ewango, C., Ntaboba, L.C., Van Oost, K., Boeckx, P. (2021) Fire-derived phosphorus fertilization of African tropical forests. Nature Communications 12, 5129.
  • Wagner, S., Harvey, E., Baetge, N., McNair, H., Arrington, E., Stubbins, A. (2021) Investing atmospheric inputs of dissolved back carbon to the Santa Barbara Channel during the Thomas Fire (California, USA). Journal of Geophysical Research: Biogeosciences 126, e2021JG006442.
  • Wagner, S., Coppola, A.I., Stubbins, A., Dittmar, T., Niggemann, J., Drake, T.W., Seidel, M., Spencer, R.G.M., Bao, H. (2021) Questions remain about the biolability of dissolved black carbon along the combustion continuum. Nature Communications 12, 4281.
  • Podgorski, D.C., Zito, P., Kellerman, A.M., Bekins, B.A., Cozzarelli, I.M., Smith, D.F., Cao, X., Schmidt-Rohr, K., Wagner, S., Stubbins, A., Spencer, R.G.M. (2021) Hydrocarbons to carboxyl-rich alicyclic molecules: A continuum model to describe biodegradation of petroleum-derived dissolved organic matter in contaminated groundwater plumes. Journal of Hazardous Materials 402,