Lake Superior is not only the largest of the Great Lakes, it is also has the largest surface area of any freshwater lake in the world. The lake stretches 350 miles from west to east, and 160 miles north to south. In addition, at an average depth of 500 feet, Lake Superior is the deepest and coldest Great Lake.
Some of the first visitors to Lake Superior were French Jesuit missionaries and explorers in the 1600s. They were soon followed by fur trappers and voyageurs. The voyageurs, who were responsible for transporting pelts, travelled from Lake Superior, down the Ottawa River to Montreal, Canada, and from there to the Atlantic Ocean.
Logging was the major industry on the lake from 1880 to 1925. Before logging, the lake was surrounded by giant Norway and white pine, spruce, fir, cedar, maple, and birch trees. By the end of the logging boom in the mid-1900s, these huge trees were exhausted and replaced by second-growth aspen, birch and poplar.
The Lake Superior Basin also contains many minerals: copper, silver and gold deposits have been discovered. But the most important mineral was iron ore.
Industries such as mining and logging contributed to some environmental problems around the lake. The four biggest threats were, and still are to a degree, oil tankers, sewage, erosion, and industrial pollution.
Industrial pollution during the 1960s grew so bad that new measures had to be implemented. At that time, Lake Superior's turbidity had increased because of taconite particle dumping. This cloudiness adversely affected light penetration, which led to a decline in bottom-dwelling fish species. Now, there are local goups and federal agencies dedicated to maintaining the health of Lake Superior by limiting dumping and regulationg overall pollution and disturbance.
