My research interests apply a wide range of methods to better understand the timing and causes of climatic changes during the Quaternary.

I have an on-going project in the tropical Andes, funded by NSF, to explore how Pacific and Atlantic Ocean processes combine to affect the pattern of glaciation on a range of time-scales. This project is in collaboration with Don Rodbell at Union College, Joseph Licciardi of the University of New Hampshire, and Bryan Mark at Ohio State University.

Through these projects we have worked extensively to collect records of glaciation from eastern and western slopes of the Peruvian Andes, as well as the northern Andes of Venezuela. We have applied a combination of terrestrial cosmogenic radionuclide dating methods and high-resolution lake sediment records to determine the timing of glacial fluctuations in these regions.

These records provide new insight into how processes like the South American summer monsoon, tropical Atlantic sea surface temperatures and ENSO in the tropical Pacific Ocean combine to drive temperature and precipitation changes across the South American continent.

I have a recent project to work in Central America that also is funded by NSF to apply carbonate stable isotope systems and climate modeling efforts to develop detailed and quantitative reconstructions of past precipitation amounts along a transect through the "dry corridor" of Guatemala, El Salvador, Honduras and Nicaragua. This project will develop new lake sediment records to compare to both proxy-reconstructions and climate model simulations of tropical Pacific and Atlantic Ocean-atmosphere variability in order to further evaluate the relative importance of these systems in driving past rainfall changes. This project is in collaboration with Byron Steinman from University of Minnesota-Duluth and Matthew Lachniet from UNLV.

I also have a research partnership with University of Oxford, where we are developing pollen-based records of past climate changes in Central America. Currently I am applying similar carbonate isotope systems to understand the climate history of eastern Europe. This ongoing project has been generously supported by grants from NIU to develop decadal-scale quantitative reconstructions of past precipitation changes from the Baltic region. This project is in collaboration with Tallinn University, Tartu University and Tallinn University of Technology.

In tandem with this project, we are focusing on peatlands as records of climate change and carbon dynamics. Northern peatlands are collectively one of the largest carbon pools in the northern hemisphere, and they are a potential major source of greenhouse gases including carbon dioxide and methane.

In order to evaluate the potential climate feedbacks associated with high northern latitude peatlands, we are working to develop longer temporal perspectives on the linkages between shifts in climate and carbon accumulation rates in these environments.