Professor of Biology, Program Chair of Environmental Science



Office: LSP232D


B.A. Wellesley College
M.S., Ph.D. University of Wisconsin


Community ecology. Understanding and predicting responses of aquatic communities to environmental change. Limnology: the ecology of inland bodies of water.

Interactive Effects of UV Radiation and Temperature on Pelagic Foodwebs

Jin Hwang's Field Work Video

30 Days of Awesome - Canadian Rockies


Overholt, E.P., K.C. Rose, C.E. Williamson, J.M. Fischer, N.A. Cabrol.  2016.  Behavioral responses of freshwater calanoid copepods to the presence of ultraviolet radiation: avoidance and attraction.  Journal of Plankton Research 38: 16-26.

Sanders, R.W., S.L. Cooke, J.M. Fischer, S.B. Fey, A.W. Heinze, W.H. Jeffrey, A.L. Macaluso, R.E. Moeller, D.P. Morris, P.J. Neale, M.H. Olson, J.D. Pakulski, J.A. Porter, D.M. Schoener, and C.E. Williamson.  2015.  Shifts in microbial food web structure and productivity after additions of naturally occurring dissolved organic matter: results from large-scale lacustrine mesocosms.  Limnology and Oceanography 60: 2130-2144.

Cooke, S.L., J.M. Fischer, K. Kessler, C.E. Williamson, R.W. Sanders, D.P. Morris, J.A. Porter, and W. Jeffries.  2015.  Direct and indirect effects effects of additions of chromophoric dissolved organic matter during large-scale mesocosm experiments in an oligotrophic lake.  Freshwater Biology 60: 2362-2378.

Leach, T.H., C.E. Williamson, N. Theodore*, J.M. Fischer, and M.H. Olson.  2015.  The role of ultraviolet radiation in the diel vertical migration of zooplankton: an experimental test of the transparency-regulator hypothesis.  Journal of Plankton Research 37: 886-896.

Fischer, J.M., M.H. Olson, N. Theodore*, C.E. Williamson, K.C. Rose, and J. Hwang*.  2015.  Diel vertical migration of copepods in mountain lakes: the changing role of ultraviolet radiation across a transparency gradient.  Limnology and Oceanography 60: 252-262.

Rose, K.C., D.P. Hamilton, C.E. Williamson, C. McBride, J.M. Fischer, M.H. Olson, J.E. Saros, M.G. Allan, N. Cabrol.  2014.  Comparison of light attenuation characteristics between glacially- and non-glacially fed lakes.  Journal of Geophysical Research: Biogeosciences 119, doi:10.1002/2014JG002674.

Rose, K.C., C.E. Williamson, J.M. Fischer, S.J. Connelly, M.H. Olson, A.J. Tucker, D.A. Noe.  2012. The role of ultraviolet radiation and fish in regulating the vertical distribution of Daphnia.  Limnology and Oceanography 57: 1867-1876.

Fischer, J.M., M.H. Olson, C.E. Williamson, J.C. Everhart*, P.J. Hogan, J.A. Mack, K.C. Rose, J.E. Saros, J.R. Stone, R.D. Vinebrooke.  2011.  Implications of climate change for Daphnia in alpine lakes: predictions from long-term dynamics, spatial distribution, and a short-term experiment.  Hydrobiologia 676: 263-277.

Williamson, C.E., J.M. Fischer, S.M. Bollens, E.P. Overholt, and J.K. Breckenridge.  2011.  Toward a more comprehensive theory of zooplankton diel vertical migration: integrating ultraviolet radiation and water transparency into the biotic paradigm.  Limnology and Oceanography 56: 1603-1623.

Rose, K.C., C.E. Williamson, J.E. Saros, R. Sommaruga, and J.M. Fischer.  2009.  Differences in UV transparency and thermal structure between alpine and subalpine lakes:  Implications for organisms. Photochem. Photobiol. Sci. 8: 1244-1256.

Course Information

110. Principles of Evolution, Ecology and Heredity. (N)

An introduction to Mendelian genetics, micro- and macro-evolutionary processes, the origin and diversification of life on earth and ecological patterns and processes at organismal, population, community and ecosystem levels. Offered every Spring. 

310. Experimental Design in Biology. (BWR)

An exploration of the challenges and rewards of experimentation in biology. In this seminar, we will use case studies to illustrate the basic principles of experimental design, including hypothesis generation, assigning treatments, replication/pseudoreplication, confounded variables and statistical power. Case studies will be chosen to represent a wide range of sub-disciplines of biology, including biomedical research. Prerequisites: BIO 210, 220 and permission of the instructor. 

323. Ecological Concepts and Applications. (N) (BWR)

Interactions of organisms with their environment and how these interactions are influenced by human activities. Special emphasis is placed on principles of population, community and ecosystem ecology. Class exercises and discussions involve critical evaluation of current research and applications of ecological concepts to conservation and management. Most labs are field-oriented, including an overnight trip to the Poconos. Prerequisites: BIO 220 and permission of the instructor. Offered every Fall.