The Great Lakes are often called America’s inland seas. These enormous lakes—Huron, Ontario, Michigan, Erie, and Superior—are so big that they touch eight different states and hold a whopping 23 quadrillion liters of water. That’s enough water to cover the entire land area of the United States with a layer three meters deep! These lakes are surrounded by forests, grasslands, and wetlands, providing a home for over 3,500 different species of plants and animals.
The story of the Great Lakes began over 10,000 years ago, near the end of the last ice age. As the Earth warmed, huge glaciers started to melt and retreat. These glaciers carved out large basins in the ground. When the ice melted, these basins filled with water, creating the Great Lakes. Over time, channels formed between the lakes, allowing water to flow between them. Today, the Great Lakes hold nearly 20% of the world’s fresh surface water.
The water’s journey starts in Lake Superior, the deepest, coldest, and clearest of the lakes. It holds half of the water in the entire Great Lakes system and is home to more than 80 species of fish. A drop of water stays in Lake Superior for about 200 years before moving on to Lake Michigan or Lake Huron. These two lakes are connected by the Straits of Mackinac and are technically considered one lake.
Lake Michigan, located to the west, is the third largest by surface area. It features the world’s largest freshwater dunes and is home to many wildlife species and fossilized coral. To the east is Lake Huron, which has the longest shoreline and is filled with ancient petrified trees. Water flows from Lake Huron into Lake Erie, the warmest and shallowest of the lakes, which attracts millions of migrating birds.
The water’s final stop is Lake Ontario, where it plunges over the famous Niagara Falls. From Lake Ontario, the water flows into the St. Lawrence River and eventually reaches the Atlantic Ocean.
The Great Lakes are not just a natural wonder; they provide many benefits. They help filter water, control floods, and cycle nutrients. They also supply drinking water to over 40 million people and provide 212 billion liters of water daily for industries and farms.
However, our reliance on the Great Lakes has led to some problems. The coastal habitats are becoming more populated and polluted by industrial, urban, and agricultural activities. Since only a small amount of water leaves the lakes each year, pollutants can linger for decades. Additionally, more than 100 non-native species, like zebra mussels and sea lampreys, have been introduced, affecting local fish populations.
Climate change is also impacting the Great Lakes by warming the waters, lowering water levels, and altering aquatic life. Fortunately, the United States and Canada are working together to reduce pollution, protect habitats, and stop the spread of invasive species. Protecting the Great Lakes is a big job, but it’s essential to preserve this incredible natural resource for future generations.
Draw a map of the Great Lakes region. Label each lake and the states or provinces they touch. Include major cities and any notable geographical features like the Straits of Mackinac or Niagara Falls. This will help you visualize the size and importance of the Great Lakes.
Conduct a simple experiment to understand how glaciers carved out the Great Lakes. Use a block of ice to simulate a glacier and a tray of sand to represent the Earth’s surface. Observe how the ice moves and shapes the sand, mimicking the formation of the Great Lakes.
Create a storyboard that follows a drop of water as it travels through the Great Lakes. Illustrate and describe its journey from Lake Superior to the Atlantic Ocean, highlighting key features and changes it experiences along the way.
Research one species of plant or animal that lives in the Great Lakes region. Prepare a short presentation about its habitat, role in the ecosystem, and any threats it faces. Share your findings with the class to learn about the biodiversity of the Great Lakes.
Participate in a debate about the challenges facing the Great Lakes. Discuss topics like pollution, invasive species, and climate change. Consider both the benefits and drawbacks of human activities in the region and propose solutions to protect these vital resources.
**Sanitized Transcript:**
What’s so great about the Great Lakes? They are known as America’s inland seas. The North American Great Lakes—Huron, Ontario, Michigan, Erie, and Superior—are so massive that they border eight states and contain 23 quadrillion liters of water. That’s enough to cover the land area of the contiguous United States three meters deep. These vast bodies of water span forest, grassland, and wetland habitats, supporting a region that’s home to over 3,500 species.
But how did such a vast and unique geological feature come to be? The story begins near the end of the last ice age over 10,000 years ago, a time when the climate was warming and the glaciers that cloaked the Earth’s surface began their slow retreat. These immense ice sheets carved out a series of basins. Those basins filled with water as the ice began to melt, creating the world’s largest area of freshwater lakes. Over time, channels developed between these basins, and water began to flow in an ongoing exchange that persists to this day. In fact, today, the interconnected Great Lakes contain almost 20% of the world’s supply of fresh surface water.
The water’s journey begins in the far north of Lake Superior, which is the deepest, coldest, and clearest of the lakes, containing half the system’s water. Lake Superior sinks to depths of 406 meters, creating a unique and diverse ecosystem that includes more than 80 fish species. A given drop of water spends, on average, 200 years in this lake before flowing into Lake Michigan or Lake Huron. Linked by the Straits of Mackinac, these two lakes are technically one.
To the west lies Lake Michigan, the third largest of the lakes by surface area. Water slowly moves through its cul-de-sac shape and encounters the world’s largest freshwater dunes, many wildlife species, and unique fossilized coral. To the east is Lake Huron, which has the longest shoreline. It’s sparsely populated but heavily forested, including 7,000-year-old petrified trees. Below them, water continues to flow southeastwards from Lake Huron into Lake Erie. This lake’s status as the warmest and shallowest of the five has ensured an abundance of animal life, including millions of migrating birds.
Finally, the water reaches its last stop by dramatically plunging more than 50 meters down the thundering Niagara Falls into Lake Ontario, the smallest lake by surface area. From there, some of this well-traveled water enters the St. Lawrence River, eventually reaching the Atlantic Ocean.
In addition to being a natural wonder, the perpetually flowing Great Lakes bring us multiple benefits. They provide natural water filtration, flood control, and nutrient cycling. By moving water across more than 3,200 kilometers, the Great Lakes also provide drinking water for upward of 40 million people and 212 billion liters a day for the industries and farms that line their banks.
However, our dependence on the system is having a range of negative impacts, too. The Great Lakes coastal habitats are being degraded and increasingly populated, exposing the once pristine waters to industrial, urban, and agricultural pollutants. Because less than 1% of the water leaves the lakes’ system annually, decades-old pollutants still lurk in its waters. Humans have also inadvertently introduced more than 100 non-native and invasive species into the lakes, such as zebra and quagga mussels, and sea lampreys that have affected some indigenous fish populations.
On a larger scale, climate change is causing the waters to warm, thus reducing water levels and changing the distribution of aquatic life. Fortunately, in recent years, governments have started to recognize the immense value of this natural resource. Partnerships between the United States and Canada are underway to reduce pollution, protect coastal habitats, and halt the spread of invasive species. Protecting something as massive as the Great Lakes system will require the collaboration of many organizations, but the effort is critical if we can preserve the wonder of this flowing inland sea.
Lakes – Large bodies of water surrounded by land, often formed by glaciers or tectonic activity. – Example sentence: The Great Lakes in North America are some of the largest freshwater lakes in the world.
Water – A transparent, tasteless, odorless, and nearly colorless chemical substance that is essential for all known forms of life. – Example sentence: Clean water is crucial for maintaining healthy ecosystems and supporting biodiversity.
Species – A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. – Example sentence: The Amazon rainforest is home to thousands of different species, many of which are not found anywhere else on Earth.
Pollution – The introduction of harmful substances or products into the environment, causing adverse effects. – Example sentence: Industrial pollution can lead to the contamination of rivers and lakes, affecting both wildlife and human populations.
Habitats – The natural environments in which a particular species lives and grows. – Example sentence: Wetlands provide important habitats for many bird species and help to filter pollutants from water.
Climate – The long-term pattern of weather conditions in a particular region, including temperature, precipitation, and wind. – Example sentence: Climate change is causing shifts in weather patterns, affecting ecosystems and species around the globe.
Glaciers – Large masses of ice that move slowly over land, formed from compacted layers of snow. – Example sentence: Melting glaciers contribute to rising sea levels, which can impact coastal communities and ecosystems.
Nutrients – Substances that provide nourishment essential for growth and the maintenance of life. – Example sentence: Nutrients from decomposed plants and animals enrich the soil, supporting plant growth in forests.
Rivers – Large natural streams of water flowing in channels to the sea, a lake, or another river. – Example sentence: The Nile River is one of the longest rivers in the world and is vital for agriculture in Egypt.
