By: Sarah Opfer
The Great Lakes, while old, are not quite as ancient as the world’s oceans. Approximately 10,000 years ago, retreating glaciers carved out basins and filled them in with melt water. As such, the Great Lakes contain 21 percent of the world’s surface fresh water and are the largest group of freshwater lakes on Earth.. That is enough water to cover the 48 contiguous United States to a uniform depth of 9.5 feet! There are five distinct Great Lake Basins: Lake Superior, Lake Huron, Lake Michigan, Lake Erie, and Lake Ontario, but they form a single, interconnected body of fresh water that is connected all the way to the Atlantic Ocean.
The first trip to the Great Lakes is surprising for people, who are often impressed and awed by their size. The total surface area of the lakes is approximately 94,250 square miles, which is nearly the same size as the United Kingdom and larger than New York, New Jersey, Connecticut, Rhode Island, Massachusetts, Vermont, and New Hampshire combined. These physical features make the region unique in many respects, and even though the lakes are not near the ocean, it does not exclude them from the impacts of marine debris.
While we may not have whales and seals that become entangled in fishing gear, our wildlife is not immune. Each year, birds, such as seagulls and great blue herons, as well as fish and other local wildlife are found entangled in debris during beach cleanups. The Great Lakes sustain an approximate $4 billion recreational fishing industry. It is not uncommon to see the shores and lakes dotted with fishermen and boats enjoying the catch of walleye, perch, and other lake species. It is also not uncommon than to see pieces of monofilament fishing line in the environment, causing an entanglement hazard for wildlife. Many states in the region have a monofilament recycling program in place or are working to establish one. This program distributes recycling bins (made of PVC pipes) in popular fishing spots and gives fisherman the opportunity to properly dispose of their discarded or lost line. We encourage you to look for one in your area!
History also plays an important role in debris issues in the Great Lakes. As settlers expanded west, the region became home to a booming lumbering industry in the late 1800s-early 1900s. Lumber mills shipped materials from the region to areas around the United States and internationally, but they also produced millions of tons of waste in the form of sawdust, woodchips, and slabwood. That waste was discarded into the Great Lakes basin.
Two hundred years later, the Great Lakes are still polluted with this unique type of marine debris. While the exact impacts of the sawdust and woodchips are unknown, it is believed that this historic material smothers the bottom-environment, limiting environmental productivity and habitat while contributing to the degradation of fish and wildlife populations. Efforts to restore areas like Manistique River in Michigan have already begun.
While we can’t prevent the historic sawdust issue, we can do something about the other debris in the Great Lakes. Remember the next time you are walking a beach or enjoying a day out on the water, to please secure your trash, properly dispose and recycle it, and pick up any other debris you might see laying around. We want to protect our unique freshwater resource!