Pink Lake is a meromictic lake located in Gatineau Park, Quebec Canada. The surface of the waters are a deep green due to the abundance of algae in the water. The lake is in danger of eutrophication due to human activities. Park management forbids swimming in the lake, walking domestic animals near it, straying from the wooden boardwalk for sight-seers, and throwing stones into the lake.

http://en.wikipedia.org/wiki/Pink_Lake