Water covers 70% of the Earth's surface, with only 2% of that consisting of fresh water. The Laurentian Great Lakes of Canada are an extremely important fresh water supply because they contain a staggering 20% of the world’s fresh water. These freshwater systems are threatened due to many factors including pollution through cultural eutrophication and invasive species.
Cultural eutrophication occurs when there are large and rapid inputs of phosphorus and nitrogen (called primary nutrients) from anthropogenic (human-related) sources including agricultural fertilizers, effluents from industry, and sewage. This can be distinguished from natural eutrophication that occurs over hundreds of years and, as a result, produces different climate conditions. Increases in the amount of nitrogen and phosphorus leads to decreased water quality and other water quality associated impairments such as increased turbidity (cloudiness in the water due to suspended sediments) and increased blue-green algal production (algae are microscopic organisms that flourish in high nutrient conditions).
Next to habitat destruction, invasive species cause the most extinctions worldwide. Since the 1800’s, more than 140 exotic aquatic organisms have become established in the Great Lakes Region alone. A couple of examples include zebra mussels (Dreissena polymorpha) and round gobies (Apollonia melanostoma). Invasive species come aboard airplanes or attached to the hulls of ships, or are carried in ballast water which is then discharged into the Great Lakes. Invasive species out-compete native species for nest sites, spawning sites, and food resources, thus altering the food web and natural functioning of the ecosystem.
What can you do to help?
Become an URBAN volunteer! URBAN will monitor water quality and use biological indicators to represent water quality in streams and wetlands of the Hamilton region. Continuous water quality monitoring is essential in detecting potential threats to one of the world’s greatest fresh water resources, the Laurentian Great Lakes.
Other changes you can make include ensuring your boat/canoe has been washed thoroughly when moving it between lakes, do not transfer plants or animals between countries/regions, and limit your use of herbicides and pesticides.