Ph.D. 2007, University of California, Berkeley, Dept. of Environmental Science, Policy & Management; M.S. 2000, University of California, Davis, Soil Science; B.A. 1989, Oberlin College.  Isotope biogeochemistry of soils in the Earth system.  Effects of disturbance (pollution, climate change) on soil-atmosphere and soil-hydrology interactions.  Innovative use of multiple isotope systems to explore the interaction of geochemical, geomorphic, and biological processes in driving biogeochemical cycling in terrestrial environments.

Recent Publications

  • Seipel, T., Jorgenson, D., Ewing, S. A., Rew, L. J. (submitted March 2, 2016), Effect of the abiotic environment and prescribed fire on vegetation composition at the interface of the Great Plains and Sagebrush Steppe. In review, Rangeland Ecology and Management.
  • Jones, M., Harden, J., O’Donnell, J., Manies, K., Jorgenson, M. T., Treat, C., Ewing, S. A (accepted 2016), Permafrost carbon loss and slow recovery following permafrost thaw in boreal peatlands. Global Change Biology, doi: 10.1111/gcb.13403.
  • Ewing, S. A., O’Donnell, J. A., Aiken, G. R., Butler, K., Butman, D.,Windham-Myers, L., and Kanevskiy, M. Z. (2015), Long-term anoxia and release of ancient, labile carbon upon thaw of Pleistocene permafrost. Geophys. Res. Lett. 42, doi: 10.1002/2015GL066296.
  • Ewing, S. A., Paces, J. B., O’Donnell, J. A., Kanevskiy, M. Z., Shur, Y., Jorgenson, M. T., Aiken, G. R., Harden, J. W. and Striegl, R. (2015), Uranium isotopes and dissolved organic carbon in loess permafrost: modeling the age of ancient ice. Geochimica et Cosmochimica Acta 152, 143-165 doi:10.1016/j.gca.2014.11.008.
  • *Johnston, C. E., Ewing, S. A., Harden, J. W., Varner, R, K., Koch, J., Wickland, K. P., Manies, K., Jorgenson. M. T. (2014) Effect of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence. Environmental Research Letters9 085004 doi:10.1088/1748-9326/9/8/085004.
  • Jorgenson M.T., Harden J.W., Kanevskiy M.Z., O’Donnell J., Wickland K., Ewing S.A., Manies K, Zhuang Q., Shur Y., Striegl R. and Koch J. (2013). Hydrologic reorganization and soil carbon changes after permafrost degradation across heterogeneous boreal landscapes. Environmental Research Letters.
  • Stoy, P. C., Johnson, A., Prieto-Blanco, A. and Ewing, S. (Accepted June 2012) Temperature, heat flux,
    and reflectance of common subarctic mosses and lichens under field conditions: Might changes to
    community composition impact climate-relevant surface fluxes? Arctic, Antarctic and Alpine Research.
  • Koch, J. C, Ewing, S. A., Striegl, R., and McKnight, D. M. (Accepted June 2012) Rapid runoff via
    shallow throughflow and deeper pipe flow in a boreal catchment underlain by frozen silt.
    Hydrogeology Journal.
  • Amundson, R., Barnes, J.D., Ewing, S., Heimsath, A., Chong, G. (2012). The Stable Isotope Composition
    of Halite and Sulfate of Hyperarid Soils and Its Relation to Aqueous Transport. Geochimica et
    Cosmochimina Acta
  • Amundson, R., Dietrich, W., Bellugi, D., Ewing, S., Nishiizumi, K., Chong, G., Owen, J., Finkel, R.,
    Heimsath, A., Stewart, B., Caffee, M. (2012). Geomorphic evidence for the late Pliocene onset of
    hyperaridity in the Atacama Desert. GSA Bulletin doi: 10.1130/B30445.1.
  • Ewing, S. A., Christensen, J. N., Brown, S. T., Cliff, S. S., VanCuren, R. A., and DePaolo, D. J. The impact of Asian air pollution on air quality in California. Environmental Science and Technology.
  • Ewing, S. A. and Singer, M. J. (expected 2010). Soil Quality. In: (G. Levy, ed.) Handbook of Soils (2nd Edition). CRC Press.
  • Amundson, R., Ewing, S., Dietrich, W., Sutter, B., Owen, J., Chadwick, O., Nishiizumi, K., Walvoord, M., McKay, C. (2008), On the in situ aqueous alteration of soils on Mars. Geochimica et Cosmochimica Acta 72, 3845-3864, doi:10.1016/j.gca.2008.04.038.
  • Ewing, S. A., Macalady, J. L., Warren-Rhodes, K., McKay, C. P., and Amundson, R. (2008) Changes in the soil C cycle at the arid-hyperarid transition in the Atacama Desert. Journal of Geophysical Research – Biogeosciences 113, G02S90, doi:10.1029/2007JG000495.
  • Ewing, S. A., Yang, W., DePaolo, D. J., Michalski, G., Kendall, C., Stewart, B., Thiemans, M., and Amundson, R. (2008), Non-biological fractionation of Ca isotopes in soils of the Atacama Desert, Chile. Geochimica et Cosmochimica Acta 72, 1096–1110, doi:10.1016/j.gca.2007.10.029.
  • Ewing, S. A., Michalski, G., Thiemens, M., Quinn, R., Macalady, J., Kohl, S., Wankel, S. D., Kendall, C., McKay, C. P., and Amundson, R. (2007), Rainfall limit of the N cycle on Earth. Global Biogeochemical Cycles21, GB3009, doi: 10.1029/2006GB002838.
  • Ewing, S. A., Southard, R. J., Macalady, J. L., Hartshorn, A. S., and Johnson, M. J. (2007), Soil microbial fingerprints, carbon, and nitrogen in a Mojave Desert creosote bush ecosystem. Soil Science Society of America Journal 71, 469-475, doi: 10.2136/sssaj2005.0283.
  • Ewing, S. A., Sutter, B., Amundson, R., Owen, J., Nishiizumi, K., Sharp, W., Cliff, S. S., Perry, K., Dietrich, W. E. and McKay, C. P. (2006), A threshold in soil formation at Earth’s arid-hyperarid transition. Geochimica et Cosmochimica Acta 70(21), 5293-5322, doi: 10.1016/j.gca.2006.08.020.
  • Ewing, S. A., Sanderman, J., Baisden, W. T., Wang, Y., and Amundson, R. (2006), The role of large scale soil structure in organic carbon turnover rates. Journal of Geophysical Research – Biogeosciences 111(G3), G03012, doi: 10.1029/2006JG000174.
  • Warren-Rhodes, K., Rhodes, K. L., Pointing, S. B., Ewing, S., Lacap, D. C., Gómez-Silva, B., Amundson, R., Friedmann, E. I., McKay, C. P. (2006), The influence of water availability on cyanobacterial community ecology and the dry limit to photosynthetic life in the Atacama Desert, Chile. Microbial Ecology 52 (3), 389-398, doi: 10.1007/s00248-006-9055-7. 

Current Instructional Responsibilities

  • Isotope Biogeochemistry (LRES 558)
  • Landscape Pedology (ENSC 454)