University of California, Riverside

Environmental Sciences

James O. Sickman

James O. Sickman

James Sickman Photo

Department Chair
Professor of Hydrology

Academic Degrees:

  • Ph.D., Watershed Biogeochemistry, U.C. Santa Barbara, 2001
  • M.A., Aquatic and Ecosystem Science, U.C. Santa Barbara, 1991
  • B.A., Aquatic Biology, U.C. Santa Barbara, 1983


  • Biogeochemistry of rivers, lakes and watersheds. Limnology of high elevation lakes. Environmental isotopes.

Research Group:

    Representative Publications:

    • Heard, A.M., Sickman, J.O., Rose, N.L., Bennett, D.M., Lucero, D.M., Melack, J.M. and CJ.H. Curtis. 2014. Twentieth-century atmospheric deposition and acidification trends in lakes of the Sierra Nevada, California (USA). Environmental Science & Technology. Vol. 48, 10054−10061.
    • Homyak, P.M, Sickman, J.O., Miller, A.M., Melack, J.M., Meixner, T. and J.P. Schimel. 2014. Assessing nitrogen impacts on chaparral ecosystems: Limitations of traditional indicators of N-saturation. Ecosystems. DOI: 10.1007/s10021-014-9792-2.
    • Bell, M.D., Sickman, J.O., Bytnerowicz, A., Padgett, P.E., and E.B. Allen. 2014. Variation in isotopologues of atmospheric nitric acid in passively collected samples during a summer monsoon. Atmospheric Environment. Vol. 94 p. 287-296.
    • Homyak, P.M, Sickman, J.O., and J.M. Melack. 2014. Pools, transformations and sources of P in high elevations soils: Implications for nutrient transfer to Sierra Nevada lakes. Geoderma. Vol. 217-218: p.67-73.
    • Sickman, J.O., Bennett, D.M., Lucero, D.M., Whitmore, T.J., Kenney, W.F. 2013. Diatom-inference models for acid neutralizing capacity and nitrate based on 41 calibration lakes in the Sierra Nevada, California, USA. Journal of Paleolimnology. DOI: 10.1007/s10933-013-9711-0.

    Courses Taught:

    • ENSC 001 Introduction to Environmental Sciences: Natural Resources
    • ENSC 163 Physical Hydrology
    • ENSC 218 Isotopes in Ecology and Environmental Science
    • ENSC 227 Global Change and the Earth System

    Graduate Program Affiliations and Research Focus Areas:


    More Information

    General Campus Information

    University of California, Riverside
    900 University Ave.
    Riverside, CA 92521
    Tel: (951) 827-1012

    Department Information

    Environmental Sciences
    Geology 2258

    Tel: (951) 827-5116
    Fax: (951) 827-3993