At around 31,000 square miles in total area, Lake Superior is the largest of the Great Lakes, not just by volume but also by surface area. It is the largest freshwater lake in the world by total surface area, measuring approximately 310 miles in length and 160 miles in width. With a surface area of around 10,000 square miles, Lake Superior covers more than 86,000 acres, making it the third-largest lake in the world by total surface area.
The shoreline of Lake Superior is around 2,900 miles long, winding through the Upper Midwest states of Minnesota, Wisconsin, Michigan, and the province of Ontario, Canada. The lake is dotted with several islands, including the spectacular Apostle Islands in Wisconsin, Isle Royale in Michigan and and the Slate Islands in Ontario. The deepest point lies around 405 feet below the lake’s surface and was discovered in 1855. The lake is bordered by the cities of Duluth and Superior Minnesota, Marquette and Houghton Michigan and Thunder Bay Ontario, making it the largest estuary in the world, nearly twice the size of the second largest, Chesapeake Bay.
The lake is part of the mighty Iroquois River system, which flows hundreds of miles throughout Minnesota and Canada. The lake is composed of two distinct basins: the northern and southern basins, which measure 1,999 and 8,000 feet in depth, respectively. About 80% of Lake Superior’s Islands are located in the northern basin. The lake is also home to some of the oldest known fish species in the world, including lake whitefish, lake trout and burbot.
The lake’s vast size and impressive depth make it an ideal habitat for numerous types of wildlife. Herds of white-tailed deer and moose can be found roaming the forests and shorelines, while bald eagles, loons and Canada geese, among other species, dominate the skies. The lake is also home to around 85 species of fish. It is estimated that the lake supports around 140 species of fish, over 35 species of birds and 10 species of mammals.
The lake is a popular destination for fishermen, boaters and campers alike, providing various recreational activities like fishing, sailing, swimming, kayaking and canoeing. It’s also a haven for scuba divers, who can explore more than 465 known shipwrecks in its waters.
The lake’s significance to the region traces back to its original inhabitants, the Ojibwe, who depended on the lake’s bounty for sustenance. The lake was also a major transportation hub during the Industrial Revolution, when steamships brought people and goods to and from the surrounding communities. But the lake has been humanized in more than one way: pollution from local industries has long been a concern.
Effects of Pollution
Due to the effects of industrial pollution in the Great Lakes region, Lake Superior has been steadily losing its water clarity in certain parts of the lake. The water is considered to be moderately polluted, largely due to urban runoff from areas along its shoreline. Contaminants in the lake water are primarily made up of industrial and agricultural chemicals, petroleum and heavy metals, although their concentrations are far below the maximum levels of the Canadian Council of Ministers of the Environment.
The health of the lake is also threatened by invasive species, such as zebra mussels and Quagga mussels, which can create massive colonies and interfere with the native species’ reproduction. These species also attach themselves to the ships and barges that traverse the waterways, allowing them to spread throughout the lake.
Ongoing efforts are being made to protect and restore the lake. Water quality monitoring is regularly done to assess the health of the lake, and the United States, Canada and Ontario governments have implemented programs to reduce phosphorus and other forms of pollution. For example, the US Environmental Protection Agency is working to protect drinking water from contamination and regulate discharges of pollutants into Lake Superior, while Ontario has enacted a nutrient-reduction program to control both point and non-point sources of nutrients.
Mining Aside
In recent years, various mining projects have been proposed along the shores of Lake Superior. One of these is PolyMet’s proposed copper-nickel open-pit mine near Duluth, Minnesota. This project has sparked controversy, since mining carries the risk of polluting the lake. Proponents of the mining project claim that the jobs generated by it are necessary for the region’s economic development, while opponents fear that it will lead to irreparable damage to the area’s natural resources, including Lake Superior.
Similarly, the proposed larger-scale Metallic Mountain iron mine has raised concerns over potential contamination of both air and water. This project, located near the Wisconsin-Michigan border, was approved by Toronto-based firm Aquila Resources in 2012 and is now awaiting additional permits. Opponents fear that it will significantly increase pollutants released into the lake.
Both of these projects address the economic and employment needs of the region, but come with risks of contamination to the lake’s ecosystem. Whether the benefits of the projects will outweigh the risks of contaminating this valuable natural resource remains to be seen.
Role of Climate Change
Like all of Earth’s freshwater sources, global warming is a concerning threat to Lake Superior. Scientists have predicted that the lake’s surface temperature has risen by around two degrees Celsius since the Industrial Revolution, with some estimates as high as 3.5 degrees Celsius. This rise in temperature may be causing the lake to lose an estimated 92 cubic kilometers of water each year.
This lack of freeze-up time could be dangerous for native species, as it affects oxygen levels and may lead to an increase in invasive species. With its reduced water levels, the lake’s biodiversity is being affected, as species move or disappear due to changes in the lake’s habitat.
Various organizations, including the Lake Superior Council, have taken on the responsibility of restoring and protecting the lake. However, there’s still much to be done in terms of climate change adaptation, pollution control and species management. Nonetheless, with continued work, Lake Superior may remain the vital source of life it’s always been.
Environmental Regulations
There are multiple organizations ensuring that Lake Superior’s resources are managed responsibly. One of these is the Lake Superior Water Resources Compact (LSWRC), an international agreement between the U.S. and Canada, as well as the governments of Ontario and Wisconsin. The agreement sets forth shared management objectives, regulations and a moratorium on new withdrawals from the lake. The LSWRC ensures that Lake Superior’s natural resources are managed in a sustainable way and that everyone in the region has access to the lake’s resources.
The Lake Superior National Estuarine Research Reserve (LSNERR) is a partnership between the National Oceanic and Atmospheric Administration (NOAA) and the Great Lakes Indian Fish and Wildlife Commission (GLIFWC). The research center’s main focus is to conduct research and provide environmental education and technical assistance involving the natural history and resources of Lake Superior.
The U.S. Army Corps of Engineers also plays a key role in the lake’s management. The agency is responsible for the maintenance and operation of eight commercial lake ports — two in Minnesota, four in Wisconsin, and two in Michigan — as well as providing regulatory oversight of the lake’s navigation channels.
Finally, the Lake Superior Binational Forum (LSBF) is a non-governmental effort to coordinate actions and build partnerships between agencies, organizations, and concerned citizens to protect and restore the lake’s natural resources. LSBF works to ensure the health of Lake Superior through pollution prevention, habitat restoration and species protection.
Economic Impact
Lake Superior has an important role in the economic development of the region, from providing fish and other resources for sustenance to the dense tourism activity that brings revenue to businesses in the area. According to a 2012 report from the Great Lakes Commission, the Great Lakes ecosystem generates $60 billion in wages and supports over 2 million jobs. These projections only increase to more than $62 billion in wages and upwards of 2.5 million jobs by 2042. Fishing, shipping and tourism account for the majority of these wages and jobs.
The Great Lakes ports play a major role in this economic activity, providing access to and from the lake. Together the ports of Duluth, Two Harbors, Grand Marais, Marquette, Houghton and Alpena handle 300 million tons of cargo each year, valued at over $7 billion. In Michigan, Lake Superior-based fisheries have an estimated annual value of $112 million, making it one of the state’s primary sectors of the tourism industry.
The lake also supports a growing tourism industry. Visitors come from all over the world to admire the lake’s wild beauty, enjoy its recreational opportunities, and learn about its history. Tourists spend over $1.5 billion annually in the Lake Superior region and visit attractions such as Canada’s first national park, Lake Superior Provincial Park.
Lake Superior is a true regional treasure, contributing to the livelihoods of millions in the Great Lakes region and providing livelihoods to countless species of wildlife and fish. With the help of numerous protection initiatives, Lake Superior can remain a vibrant economic and ecological resource for generations to come.
