After graduating from the University of Manitoba with a Bachelor of Science majoring in Botany, Winnipeg native Cassie Leclair landed a job as Crew Leader with Ducks Unlimited Canada (DUC). It was with Ducks Unlimited Canada where Cassie gained significant experience working with climate change issues on a greenhouse gas and carbon sequestration project in the Prairie Pothole Region. When the project sites expanded to include Ontario and Nova Scotia, Cassie saw an opportunity to further her education and travel east to the Maritimes.

Cassie is enrolled in the Master of Science program at NSAC under the supervision of Dr. David Burton, former Climate Change Research Chair at NSAC. She is researching the role of local hydrology and riparian zones in nitrous oxide (N2O) emissions. Ducks Unlimited Canada funds her graduate studies program.

N2O is an important greenhouse gas that accounts for 70% of the Canadian anthropogenic greenhouse gas emissions from the agricultural sector. The main source of N2O emissions comes from nitrogen based fertilizer use, unlike non-agricultural sector where the largest source of N2O emissions is from energy use, for example motor vehicle and residential sources.

Ultimately, through her research, Cassie hopes to better understand the spatial and temporal patterns of N2O production, as well as some of the controlling factors. In order to do this, she set up trials at a cooperator field on the Thomas Brook Watershed of the Annapolis Valley, NS. Measurements for greenhouse gas emissions are taken weekly throughout the year (monthly during winter months) using greenhouse gas chambers, which are set up in a corn field, as well as through a riparian zone down near a brook. She also takes weekly soil samples for nutrient analysis along with periodic denitrification, denitrifier enzyme activity and microbial biomass measurements.

Cassie hopes her research will aid in the creation of management practices in order to reduce N2O emissions in agriculture. “If we understand the timing and range of N2O emissions, as well as the controlling factors behind N2O production, we can work on creating better management practices, and hopefully mitigate the amount of N2O emitted to the atmosphere.”

Right now, Cassie is concentrating on data collection which should be completed in December. So far, her results support the statement that N2O emissions vary temporally but also spatially. Preliminary results show the cropped portion of the field has significantly higher N2O fluxes and soil nitrate concentrations than in the riparian zone. According to Cassie, this was expected since the crop is fertilized twice per summer. Also, the summer months show much higher N2O fluxes than the rest of the year.

“Another interesting thing I’m seeing is that soil nitrate levels show that the riparian zone appears to be acting as an efficient buffer,” says Cassie. “The riparian zone is filtering out ground nitrates before they research the adjacent brook, in fact, most soil nitrate is filtered or used within the first 5 meters of the riparian zone.”

Although only halfway through her program, Cassie’s research is already starting to create some buzz. In 2006, she was awarded the Syngenta Crop Protection Graduate Scholarship and in 2007 won Best Oral Presentation at NSAC Graduate Research Day.

“After I finish my Masters program, I would really love to do some traveling or internship overseas before settling down into a full time job. My main priority is finding something I love doing and is in the field of environmental research, especially with water quality and greenhouse gas issues.

Quick Facts

• Agriculture contributes to 8% of Canada’s total greenhouse gas emissions.
• N2O represents just over 2% of greenhouse gas emissions, the largest source being CO2 at 93% of total emissions. However, 87% of N2O emissions come from agriculture.
• N2O has global warming potential 300 times that of CO2.
• Ducks Unlimited Canada conserves, restores and manages wetlands and associated habitats for North America’s waterfowl. These habitats also benefit other wildlife and people.
• Agricultural expansion is the major cause of 85 percent of Canada's wetland losses.
Excerpts taken from Environment Canada website for Information on Greenhouse Gas Sources and Sinks (Last updated November 30, 2006). http://www.ec.gc.ca/pdb/ghg/onlinedata/downloadDB_e.cfm and Ducks Unlimited Canada website http://www.ducks.ca.