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The report evaluates floating treatment wetlands (FTWs) as a nature-based solution for eutrophication in shallow lakes. Through primary research at the IISD-Experimental Lakes Area (IISD-ELA) and a case study of Pelican Lake, Manitoba, the study demonstrates that FTWs—particularly those using cattails—effectively sequester phosphorus and nitrogen. While plant biomass contributes to nutrient removal, the report emphasizes that the microbial biofilm on roots provides up to 80% of the total treatment. For Pelican Lake, the study estimates that 5% surface coverage could reduce total phosphorus levels by 10% to 50%, though FTWs must be combined with watershed-level strategies to meet provincial water quality standards.

The study establishes a nutrient mass balance for Pelican Lake, Manitoba, finding that the lake acts as a net sink for phosphorus and a net source of nitrogen. External nutrient loads are strongly linked to surface hydrology and agricultural land use, with internal recycling from sediments contributing significantly to phosphorus levels. The findings suggest that remediation should focus on high-agricultural sub-catchments and the regulation of the Pembina River inlet dam.