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:

  • Graduate Students
    Jacob Ashford - Ph.D., Environmental Sciences Program
    Paleolimnology of Alpine Lakes
  • Other
    Peter Homyak - Ph.D. 2012, University of California, Riverside - Post Doctoral Researcher
    Steve Sadro - Post Doctoral Researcher
    Studies lake foodwebs and metabolism in the Sierra Nevada
    Kevin Skeen - Staff Research Associate
    Field manager for Sierra Nevada research
    Forugh Arsalan - Undergraduate researcher
    Tyler Davenport - Undergraduate researcher
    Micaelina Martinez - Undergraduate researcher
    Krystal Vasquez - Undergraduate researcher

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