A recent study conducted by a team of researchers from Manitoba and Saskatchewan reveals that a commonly used fertilizer, crucial for feeding a significant part of the global population, could be negatively impacting almost half of the freshwater bodies in the Canadian Prairies.
Cale Gushulak, an assistant professor at the University of Manitoba, highlights that approximately two-thirds of the world’s population relies on nitrogen-based fertilizers like urea for food production. However, there has been limited research on the effects of urea on aquatic environments.
In an experiment conducted by researchers from the University of Manitoba and University of Regina, urea was introduced into farm ponds in Saskatchewan to mimic the consequences of agricultural fertilization in the southern Prairies. The results showed a substantial increase in the growth of microscopic algae, leading to oxygen depletion in the ponds.
Gushulak emphasizes that when fertilizers seep into water bodies instead of remaining on land for crop growth, it triggers severe water-quality deterioration. Given the widespread use of urea globally, this poses a significant concern.
The study indicates that excessive algal growth resulting from urea infiltration is causing rapid oxygen depletion in surface waters, leading to fish mortality, elevated toxin exposure, and intensified harmful algae blooms. This situation pushes freshwater ecosystems towards an “ecological tipping point.”
An analysis of various water bodies across southern Saskatchewan suggests that nearly half of the lakes, wetlands, and reservoirs in the Prairie region could be adversely affected by prolonged urea application.
Moreover, the research highlights the vulnerability of agricultural regions in China and the United States to similar damages from urea use. Gushulak stresses the need for innovative fertilizer technologies and better land management practices to prevent urea from entering freshwater systems.
Asim Biswas, a professor at the University of Guelph, acknowledges the significance of the study but cautions against overlooking the interaction of urea with phosphorus in water ecosystems. He suggests that water bodies with high phosphorus levels are more susceptible to urea impacts.
While acknowledging that high phosphorus levels are a prerequisite for urea’s effects, Gushulak notes that many Prairie water bodies naturally have elevated phosphorus levels or have accumulated them due to prolonged fertilizer use.
The study’s observations challenge the perception of Canada as having abundant freshwater resources, revealing ongoing issues with water quality degradation. Gushulak warns that continued urea contamination could deteriorate water quality, making water resources more expensive and less reliable as climate changes affect water availability in the Prairies.
The research underscores the need for sustainable agricultural practices to safeguard freshwater ecosystems and ensure water security amid evolving environmental conditions.