The Great Lakes In Canada

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Introduction
The Great Lakes, including Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario, are the largest freshwater lakes in the world, accounts for about 18% of the world 's fresh water resources. They are rich in water and other resources and the area of the Great Lakes extend more than 1200 km. The storage capacity of Great Lakes is about 23000 km3 and the surface area is around 244000 km2. Nowadays 1/10 of the Americans and a quarter of Canadians live in the lakes. Some of the world 's largest industrial center is built on here. Almost 25% of total agricultural production in Canada and 7% in the United States will yield in this area. Although the area of the lake is large, it could be affected by a wide range of pollutions …show more content…

The lakes which have small algae propagation are called oligotrophic lakes. Accordingly the lakes which have large algae propagation are called eutrophic lakes. There are many factors to determine the algae propagation in a lake such as temperature, light, depth, size of the lake and nutrients from the surrounding environment, etc. In fact the Great Lakes were all oligotrophic lakes before industrialization. The factors such a size, depth and climate would keep the lakes cool and clear for a long-term. There is only a small amount of fertilizer and organic matters decompose from forest areas in the lakes at that time. Due to reduction of vegetation and thermal pollution, the temperature of many tributaries of the lake has been increased. Other than that highly concentrated city and agriculture makes a lot of nutrients and organic matter, such as inorganic phosphorus detergents and fertilizers, flowing into the lake increased nutrient content. In fact the increasing nutrients stimulate the growth of green plants such as algae. The plant will decompose after death and decomposition process consumes dissolved oxygen in the water. As a result some fish will died from lack of oxygen and the green plants will experience a highly growth resulting in the cloudy water which means increasing eutrophication process. Lake Erie has the highest biomass yield mainly because it is the shallowest water, the highest temperature of the lake so that it is the first and most serious eutrophication lake of the Great Lakes. The other reason is that the development of agriculture and the city in the earlier period reached a higher level. About 1/3 of the population of the Great Lakes area lives in Lake Erie region. This leads to the highly higher flow of contaminants to Lake Erie than any other lakes. It is generally agreed that Lake Erie was dying In Canada and the United States. Water polluted warning signs are visible

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