TORONTO - A new report is urging action to quell seasonal algae blooms in the Great Lakes, which can become partially covered by a blue-green film in the summer months.

Algae blooms are caused by an excess of nutrients such as phosphorus, which can cause algae to grow out of control.

The report -- issued by the environmental groups Environmental Defence and Freshwater Future -- outlines steps for reducing nutrient pollution in the Great Lakes.

In recent years algae blooms have become a concern for lakeside communities because of beach closures, water treatment costs and health threats, as well as the negative impact on property values.

One bloom on Lake Erie earlier this summer resulted in a temporary water ban in Toledo, Ohio.

Researchers are suggesting the Ontario government look at economic incentives to encourage farmers to actively reduce phosphorus run-off, which washes into the lakes to contribute to algae blooms.