MMy research interests focus on understanding how humans and their activities are affecting freshwater ecosystems at both local and global scales. Some of my current projects include the effects of urban and agriculture land use on the biogeochemistry and ecosystem function of aquatic ecosystems, the linkage between hydrological variability in lakes and rivers (water regulation, flooding, climate change). My primary research program studies dissolved organic matter (DOM), how it links to the physical, chemical and biological components of aquatic ecosystems to address the consequences of global change drivers. Ultimately my long-term goals are to understand how DOM composition and its interactions with climate, landscape and other ecosystem drivers (e.g., nutrients, temperature) affect the structure and function of lakes and rivers.
Current projects in my lab include:
We have been working in this research area for almost two decades, funded primarily by the NSERC Discovery Program and Canada Research Chair. We have completed extensive research linking river and lake DOM dynamics to land use, climate and other human activities. We have found that anthropogenic land use modifies DOM quality in freshwater ecosystems, mobilizes fossil DOC, controls food webs (e.g., benthic diatom biodiversity and increases ecological functions such as microbial activity, community respiration, enzyme activity, and nutrient uptake. While our knowledge of DOM chemistry has progressed rapidly over the past decade, there remains a need, and with this CRC I propose, to better integrate this knowledge into an ecosystem-level understanding to better model both C fluxes across waterscapes and the ecological functioning of freshwater.
There is now increasing evidence that non-linearity is a common response in ecological systems to pressures caused by human activities. Using long-term datasets we are focusing this research theme to: 1) better understand non-linearity in freshwaters and the environmental drivers that moderate non-linearity and 2) detect sudden transitions to find early-warning signals to better anticipate and manage regime changes. We are applying this framework to several systems including using RAEON high-frequency data collected using autonomous instruments for early indicators of algal blooms in Lake Erie and other long-term monitoring datasets to detect regime changes (e.g., Lake Simcoe).
We are involved in a few projects to better understand how water levels, high flow events and floods affect river and lake ecosystem services and function. This is currently being completed under the funding of an NSERC Strategic Network Grant (FloodNet) focused on improving flood forecasting systems and management capacity in Canada. We are also characterizing natural water levels in lakes and rivers to explore the effects of dams as well as the used of concentration-discharge curves for ecosystem management.
Initially funded by an NSERC Strategic Project we are currently constructing a carbon balance of Lake Erie. With additional funding from the CRC program, we are now expanding this to include DOM composition into C-budgets as well as expanding these measurements to others lakes and rivers. To determine the quality of DOM exported by aquatic ecosystems and whether they act as a sink or source of carbon, we will incorporate DOM quality measurements into studies of short (e.g., storm events) and longer term (2-year field seasons) fluxes of DOC, inorganic carbon (DIC, CO2), particulate carbon and nutrients entering and leaving several streams and lakes of contrasting average DOM composition.
See a list of publications located on the Publications page.
I currently teach/have taught several classes in ecology:
My research is interdisciplinary and I expect students in my lab to master a range of numerical techniques and analytical chemistry skills (or be willing to learn them). Generally, students in my lab are encouraged to develop independent scientific research and be highly motivated. If you select a field of study that you are not really interested in, the temptation to drop out when things become difficult will be high. I welcome any inquiries from students with backgrounds in ecology, environmental sciences, environmental chemistry or geography. Students are encouraged to employ field, laboratory and theoretical approaches to their work. See a list of opportunities on the Opportunities page.