How Does a Lake Die? <br>(After L. Pringle) <br><br>LAKE ERIE * IS DYING. <br>DEATH OF A GREAT LAKE. <br>LAKE ERIE: A DEAD SEA. <br>People in the U.S. and Canada may read headlines like these in newspapers or see reports on television about Lake Erie. This big lake is not dead yet, but it is in danger of dying. <br>Like many lakes in North America, Lake Erie was born more than 10,000 years ago. Its area is 25,745 square kilometres. Lake Erie is the oldest and shallowest of the Great Lakes, so it is natural that it is dying faster than the others. <br>But it is dying not only because a lot of soil, dead plants, and animal materials are carried into it. Pollution is the greatest danger. Waste products of many kinds are brought into the lake by rivers from cities and industries. Some of the wastes kill fish and some kill the life at the bottom of the lake. When plants are growing in the lake die, they go down to the bottom. The same thing happens to plant life that falls into the water. There they decay. But the process of decay is impossible without oxygen, and in Lake Erie there is so much waste that most or all of the oxygen is taken from the water. Most of the decay stops, and the wastes accumulate on the bottom. It was found that over 2,500 square kilometres of the lake's bottom waters have no oxygen at all. <br>As decay takes oxygen from the water, the animal life becomes very difficult in Lake Erie. The fish that are best for food are disap'pearing. They need very much oxygen. <br>The pollution of Lake Erie is a great danger not only for fish, but for people too, especially for children. In many places swimming in its waters is impossible now because of the danger to their health. <br>Biologists think that Lake Erie will take no less than two years to clean itself of undecayed wastes if all pollution is stopped now. City and state governments in both Canada and the United States are trying to clean up Lake Erie and put a stop to the thousands of tons of industrial and city wastes that flow into the lake. But progress is slow, and much money is needed, both by city and state organizations and by factories to do the work well. <br>There is also another thing that experts worry about: navi'gation on the Great Lakes. There are many important ports both on the US side and on the Canadian side. Will the Great Lakes be useful for navigation in the future? The waste products thrown into the water by cities and industries, together with the mud brought down by the rivers, may make the lakes very shallow and swampy and useless for navigation. The Great Lakes may become swamp-land and lost in future to the economy both of Canada and the United States.
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