The morning fog lifted slowly from Potter’s Marsh as I followed Melissa Chang through tangled cattails. The University of Saskatchewan hydrology researcher paused occasionally, kneeling to collect soil samples that would later reveal uncomfortable truths about what happens when we drain these complex ecosystems.
“Most people think of wetlands as mosquito breeding grounds or obstacles to farming,” Chang told me, carefully sealing another soil sample. “But they’re actually sophisticated carbon sinks and water filters that have evolved over thousands of years. When we drain them, we’re releasing more than just water.”
What her team is discovering could reshape how we view wetland management across Canada. New research from the University of Saskatchewan suggests that draining wetlands—a common practice to increase agricultural land—may be triggering the release of mercury into the atmosphere at rates previously unrecognized.
Since 2021, Chang and her colleagues have been studying dozens of sites across Saskatchewan’s prairie pothole region, comparing intact wetlands with those recently drained. Their preliminary findings show mercury emissions from drained wetlands can be up to seven times higher than from undisturbed sites.
“Mercury occurs naturally in small amounts,” Chang explained as we walked the perimeter of a partially drained marsh. “But when wetlands are drained, the soil dries and microbes convert this mercury into gaseous forms that enter the atmosphere much more readily.”
The research, partially funded by Environment and Climate Change Canada, comes at a critical time. Saskatchewan has lost approximately 40 percent of its original wetlands, primarily due to agricultural expansion. Across Canada, wetland loss ranges from 65 to 80 percent in settled areas according to Ducks Unlimited Canada.
Dave Olson, who farms 800 acres near Saskatoon, has been watching the research with interest. “My grandfather drained wetlands without a second thought—that was just what you did to make a living,” he said as we toured his property where he’s now working to restore several wetlands. “But we’re learning more about the consequences. It’s not just about ducks and frogs anymore.”
The mercury connection adds a troubling dimension to wetland conservation efforts. Mercury is a potent neurotoxin that bioaccumulates in the food chain, posing particular risks to developing fetuses and young children. While natural mercury emissions are part of Earth’s cycles, human activities that accelerate these emissions cause concern.
Dr. Sarah Williams, an environmental toxicologist with Health Canada who isn’t involved in the Saskatchewan study, explained the potential implications. “Mercury doesn’t stay local—it can travel globally in the atmosphere. It eventually deposits in water bodies where it converts to methylmercury and enters the food chain, particularly in fish.”
The research team emphasizes that their work isn’t meant to vilify farmers or landowners who have drained wetlands. Rather, it highlights the complex interconnections between land management decisions and environmental health.
“We’re not pointing fingers,” said Dr. James Richardson, the principal investigator on the project. “We’re identifying processes that nobody fully understood before. This gives us the opportunity to develop better management strategies.”
When I visited the research lab in Saskatoon, technicians were analyzing samples from dozens of sites. The methodical work stands in stark contrast to the rapid pace of wetland drainage across the prairie provinces. Using specialized chambers placed on wetland soils, researchers can measure the exact rate of gaseous mercury emissions under different conditions.
Beyond mercury concerns, the study reinforces what many Indigenous communities have long emphasized about wetland importance. Elder Joseph Merasty from the Lac La Ronge First Nation has been consulting on the project, bringing traditional knowledge about wetland ecosystems.
“Our people have always understood wetlands as purifiers and providers,” Merasty told me when we met at a community gathering near the research site. “The plants, the insects, the birds—they all work together. When you break that connection, everything suffers.”
The research has attracted attention from policymakers. The Saskatchewan Water Security Agency has expressed interest in incorporating the findings into their wetland policy framework. Currently, permits are required for drainage projects, but enforcement has been challenging.
“Having this kind of concrete evidence about mercury emissions gives us another factor to consider in the permitting process,” said Agency spokesperson Melinda Taylor. “It’s no longer just about flood mitigation or habitat—there are potential human health considerations too.”
For landowners considering wetland drainage, the implications are significant. While draining can increase arable land in the short term, the environmental costs may be higher than previously understood. The research team is developing guidelines for minimizing mercury emissions when drainage is unavoidable.
Alternative approaches are gaining traction. Wetland restoration projects have increased by 35 percent across Saskatchewan over the past five years. Payment for ecological services programs, where landowners receive compensation for maintaining wetlands, have shown promise in Manitoba and Alberta.
Back at Potter’s Marsh, Chang showed me a restored wetland adjacent to the drained site we’d been sampling. The difference was striking—diverse plant life, visible wildlife, and healthier-looking soil.
“Restoration isn’t perfect,” she admitted. “These systems took centuries to develop. But we’re seeing that within five years of rewetting, mercury emissions drop significantly and biodiversity begins to recover.”
As Canada works toward its commitment to conserve 30 percent of lands and waters by 2030, the Saskatchewan mercury research offers another compelling reason to protect remaining wetlands and restore what’s been lost.
Standing at the edge of the marsh as evening approached, watching birds return to roost, I was reminded that these ecosystems represent more than just environmental services. They are complex living networks that connect water, land, wildlife, and human communities in ways we’re only beginning to fully understand.
