I study community and ecosystem dynamics of lakes and rivers. I am broadly interested in how these systems work and how we can manage and conserve them. Much of my research focuses on lake food webs, particularly benthic processes, carbon fluxes, and terrestrial subsidies. Click below for brief overviews of recent and ongoing projects.
Sensor networks to describe ecosystem processes in lakes
My current position is as a postdoctoral researcher with the Global Lakes Ecological Observatory Network (GLEON). We are using high-frequency data from networks of instrumented buoys to describe ecosystem processes in lakes and predict how these processes will respond to global environmental changes.
Allochthonous subsidies to lake food webs
To what extent are consumers in lakes supported by subsidies of organic carbon from terrestrial ecosystems? We have been working to answer this question using 13C additions in a number of experimental lakes in northern Wisconsin and Michigan. More recently, we have begun to ask why utilization of these subsidies varies among consumers and ecosystems. Answering this question will require measuring subsidies in many lakes across the landscape, and we are evaluating the use natural abundance deuterium:hydrogen stable isotope ratios to facilitate such measurements.
Denitrification in a tropical stream
Accelerating land use changes are altering the nitrogen cycle in tropical aquatic systems. These productive and diverse systems are often N-limited, yet key N-cycle processes are relatively poorly described in these systems. We quantified rates of streambed denitrification in the Andean piedmont of Venezuela, and investigated the controls on those rates. Interestingly, our results suggest that anthropogenic sedimentation from forest clearing may result in increased rates of denitrification in streams.
Invasive Chinese mystery snails
The Chinese mystery snail (Bellamya chinensis) is a large viviparid snail native to Asia but widely introduced throughout North America. Using surveys and experiments, we have been trying to understand the distribution and potential impacts of this species in northern Wisconsin lakes. We found B. chinensis in ~50% of surveyed lakes that supported snails of any species. B. chinensis appears to have weak effects on most native snails, although it may be altering primary production and nutrient cycling in benthic habitats when it is abundant.
Benthic-pelagic coupling in lakes
In many lakes, fishes rely heavily on both benthic (lake-bottom) and pelagic (open water) energy pathways. To what extent does the relative importance of these different pathways vary over time? Using stable isotope analyses of museum-archived fish scales, we have been working to answer this question, and to explore how changes in energetic pathways may correlate with measures of population performance, such as individual growth rates. In addition, we have made depth-specific measurements of benthic secondary production in order to understand the distribution of potential benthic food sources for fishes.
Rainbow smelt, interaction strengths, and fisheries management
Rainbow smelt (Osmerus mordax) are native to the Atlantic coast of North America but have been introduced to many lakes in the interior of the continent, including in Wisconsin. We have been studying the interactions between smelt and several native fish species in Sparkling Lake, where the Long-Term Ecological Research project has been monitoring fish populations for more than 25 years. One focus of this work is on using the interactions between smelt and cisco as a model for understanding different ways to measure interaction strengths in food webs. Another focus is on trying to understand the pre- and post-invasion food web configurations and fisheries management actions that may influence the food web implications of smelt invasion.