Main	Current Research	Teaching	Publications	Previous Research	Service	Awards and Grants
Erin R. Hotchkiss Current Research Projects Linking carbon and oxygen cycling in streams and rivers (2007 – Present) Global carbon and oxygen cycles are directly linked to the productivity and respiration of biological communities. Using the natural abundance of δ^18O-O2 coupled with carbon isotope tracers, I hope to address the potential underestimation of daytime respiration rates in aquatic systems. I am also interested in comparing diel cycles in community respiration with potential drivers of these cycles: changes in temperature and DOC availability. Assistance with this project: R.O. Hall (Wyoming), B. Roberts (ORNL), T. Lehnertz (Wyoming), R. Crosby (Wyoming) and E. Anoszko (Gustavus Adolpus). [Photos] Seasonal changes in DOC quantity and quality in high-altitude lakes (2008 – Present) Bioavailable DOC (dissolved organic carbon) is an important source of carbon for heterotrophic bacteria in aquatic systems. I will monitor seasonal changes in the concentration and quality of DOC in several high-altitude lakes in southeastern Wyoming. Assistance with planning and executing this project: T. Lehnertz, A.J. Ulseth (Wyoming) and R.C. Musselman (GLEES). Controls on nitrate uptake in streams (2007 – Present) This project will focus on the roles of hydrology and geomorphology in nitrogen uptake along three different reaches of Red Canyon Creek, Wyoming. I will compare nitrate uptake with rates of community respiration and whole stream metabolism over 24-hour cycles. I am also using Red Canyon Creek as one of the sites for my δ^18O-O2 preliminary data. Collaborators: L.K. Lautz, K.A. Hubbard and M.J. Mitchell (SUNY-ESF). [Photos] Exotic snails and carbon cycling (2006 – Present) Invasive snails can alter inorganic carbon cycling via additional carbon dioxide (CO2) released during calcification. Research for my M.S. focused on the impacts Melanoides tuberculata in Kelly Warm Springs, Grand Teton National Park (USGS NAS).  I am also interested in the effect of this invasion on native invertebrates and the role of Melanoides as an intermediate host for parasites in Wyoming. M.S. Committee: R.O. Hall, A.C. Krist, and E.G. Pendall (Wyoming). Other assistance from: S. O’Ney (NPS), N. Swoboda-Colberg, R. Crosby, J.S. Meyer, C. Boese, J. Theurer, T. Lehnertz (Wyoming) and E. Anoszko (Gustavus Adolpus). [Photos] Denitrification in a tropical stream (2005 – Present) The loss of important fish species may change the role of denitrification in due to reduced grazing and fish N content lost from Venezuelan rivers.  Land use changes and increased sedimentation also alter benthic substrate and N availability, both important factors in denitrification.  The goal of this project is to quantify the role of denitrification in Rio Las Marías and compare these rates to N loss via fish harvest.  Assistance with planning and executing this project: C.T. Solomon (Wisconsin-Madison), R.O. Hall (Wyoming), K. Capps (Cornell), A.J. Ulseth (Wyoming), J. Figueredo (Guanare, VZ), M. Baker (Utah State), A.S. Flecker (Cornell), M. Marshall (Georgia) and C.P. Arango (Notre Dame). [Photos]