Distinguished Research Professor
UW Center for Limnology
Carbon cycling: Lakes play important roles in carbon cycling at the watershed, regional, and even global scales. The balance between carbon sequestration and evasion in lakes depends on how ecosystem boundaries are drawn, the nature of the lake and the load, and the time scale of interest. My research in carbon cycling focuses on how ecosystem processes alter these balances across different space and time scales in different ways among lakes of the world. Carbon cycling as a theme pervades work in a number of my funded research projects.
Lake metabolism and phytoplankton: Although some of my past work has emphasized fish bioenergetics and fish identification through software and modeling tools, I’ve recently downsized in organisms. The control over microbial (bacteria and phytoplankton) dynamics in real ecosystems remains a mystery under many conditions. Through partnerships with microbial ecologists and physical limnologists at the University of Wisconsin and in the Global Lake Ecological Observatory Network (GLEON), we are using high-frequency sensor network measurements, coupled physical-chemical-biological models, and signal processing to study the vagaries of microbial dynamics. Studies of algal blooms, for example, are central to much of the research happening on Lake Mendota in Madison, Wisconsin.
Modeling and CI: Melding data repositories with dynamical (mostly) models is near an obsession. Numerical simulation models, such as GLM-AED, provide coupled hydrodynamic-water quality models that enable us to inspect the details of nutrient cycling and metabolism. Simpler models, such as the integrated catchment-lake model, a.k.a. The Age of Water and Carbon model, allow for a rapid assessment of catchment-scale responses to land use and climate change. And simple lake models, such as those innovated for organic carbon cycling, enable us to quantify mass balance and major fluxes in a variety of lakes under a variety of circumstances.