The Manitoba government has ordered an overhaul on Winnipeg's wastewater treatment system to the tune of $1.8 billion. An extra $50 million will be spent on treatment processes to remove nitrogen from wastewater that ends up in Lake Winnipeg.

"We disagree with the government's plans to improve the health of Lake Winnipeg by making minor reductions in inputs of both phosphorus and nitrogen, rather than making much larger reductions in phosphorus alone," the scientists said.

Scientists say the blooms of blue-green algae plaguing Lake Winnipeg are a result of phosphorus and not nitrogen. The letter originated at an October 2008 conference at the University of Winnipeg organized by the Lake Winnipeg Foundation.