Lake Champlain Ecosystem

• Category: Inland Aquatic Biomes
• Geographic Location: North America
• Summary: Lake Champlain, the sixth-largest freshwater body in North America, is home to a variety of water and land species, but human activities have compromised the ecosystem with toxic runoff and non-native species.

Often referred to as the sixth Great Lake, Lake Champlain is a large freshwater lake bordering Canada and the United States. The lake and its basin are home to a wide variety of aquatic and terrestrial inhabitants, creating a complex community in which many species of plants and animals depend on one another to survive. Lake Champlain is an essential resource for food and shelter for plants, animals, and humans, 600,000 of whom rely on the lake for its natural and recreational resources.

More than 12,000 years ago, glacial ice covered the area where Lake Champlain exists today. As the glaciers melted, the Atlantic Ocean advanced, creating the Champlain Sea. As the glaciers retreated and the Earth's surface rebounded, the sea became isolated from the ocean and became the freshwater lake it is today. Named for Samuel de Champlain, whose explorations brought him to the area in 1609, the lake has a surface area of about 435 square miles (1,127 square kilometers) and an average depth of 64 feet (20 meters), though at its deepest point, it reaches 400 feet (122 meters). Its borders lie within the states of Vermont and New York as well as the province of Quebec in Canada.

The lake is divided into five major parts. South Lake is very thin and narrow in appearance, like a river. Main Lake contains approximately eighty percent of the lake's water and including the deepest and widest points of the lake. Mallets Bay is the most isolated section due to causeways, resulting in restricted circulation of its water. The Inland Sea, often referred to as the Northeast Arm, is much smaller than Main Lake. Finally, Missisquoi Bay is the most northeastern point of the lake. It is very shallow with a maximum depth of fourteen feet (four meters).

Biodiversity

Lake Champlain's numerous inhabitants include many plants, algae, and several species of birds and fish, creating a very intricate food web. While the lake contains blue-green algae, which can produce toxic blooms, the largest algae community comprises unicellular algae called diatoms. This algae captures solar energy and acts as food for the zooplankton living in the lake. Diatoms feed the fish in the lake, which currently contains more than one hundred native underwater plant species. These plants may appear to be weeds but provide food and shelter for numerous kinds of fish, snails, and eels.

More than seventy fish species are native to the lake, including minnows, dace, perch, bass, catfish, pike, walleye, and sturgeon. Lake Champlain once was home to Atlantic salmon and trout, but both have likely disappeared due in large part to the construction of dams.

Throughout the year, the lake provides food and shelter to more than 300 species of birds as part of the migration routes of the Atlantic Flyway. Warblers, hawks, ducks, snow geese, gulls, and double-crested cormorants are among these itinerant inhabitants.

Threats and Conservation

Lake Champlain also helps sustain the area's human population, with thirty-five percent of the local community using the lake as a source of drinking water. It also serves as a food source for local fishers. It provides for the livelihood of others who live in tourism and recreational pursuits. The United Nations has designated Lake Champlain's watershed an International Biosphere Reserve due to its natural resources.

The lake faces several environmental issues that threaten to disrupt its ecosystem, including phosphorus, a naturally occurring nutrient necessary for plant growth. Agricultural activities and industrial discharges near the lake have created a surplus of phosphorus, leading to toxic algae blooms and increased plant growth that harms fish and humans. Attempts to lower phosphorus levels in the lake, orchestrated by both Vermont and Quebec, have been ongoing for most of the early twenty-first century. Though agriculture is the primary source of phosphorus in the basin, runoff from household use also contributes. For this reason, Vermont banned the use of phosphates for dishwashing starting in 2010. Pollution from agricultural and industrial activities has led to the introduction of other toxins into the lake, such as mercury, that poison the fish and the predators and people who eat them. Human activities, including recreational boating and nonnative or exotic species that have found their way into the water via connecting canals and rivers, have added further damage. Lake Champlain has forty-six exotic species, such as zebra mussels and the underwater Eurasian watermilfoil. These invasive species threaten native plants and animals.

Another threat that may exacerbate all the others is climate change. Scientists report that the average annual air temperature in the Lake Champlain region has risen to 2.1 degrees F (1.2 degrees C) since 1976. Ice cover has diminished—while the lake froze over completely most winters until the 1950s, it did so in only three of the ten years from 2006 through 2015—meaning that more water evaporates from the lake's surface during winter. Lack of ice is also a hardship for various plant and animal species. With more precipitation coming in rain rather than snow, springtime groundwater recharge is challenged, putting stress on the wetland areas around the lake. Warmer water temperatures tend to favor the invasive species over some of the vital native types, such as salmon and northern pike. Climate change is also anticipatedto cause an increase in precipitation in the northeast, leading to more flooding and erosion, which in turn is expected to lead to an increase in pollutants in the lake. As of 2022, scientists were concerned that because the state of Vermont was getting warmer and wetter, Lake Champlain was more likely to flood, as it did in Vermont in 2019. Overall, such trends and impact factors are expected to intensify in the years ahead.

The Lake Champlain Basin Program—a partnership of Vermont, New York, Quebec, and other governments—is working to eliminate the environmental threats by creating plans of action to reduce pollution and phosphorus runoff and by engaging the public to help restore and preserve the lake for future generations. Another organization, The Lake Champlain Land Trust, is working to protect significant islands, shoreline areas, and natural communities in the Lake Champlain region.

Bibliography

Howland, William, et al. Lake Champlain—Experience and Lessons Learned Brief. Lake Champlain Basin Program, 2006.

Marsden, J. Ellen, and Michael Hauser. "Exotic Species in Lake Champlain." Journal of Great Lakes Research, vol. 35, no. 2, 2009, pp. 250-65.

Sorg, Summer. "Will Lake Champlain Flood? Waters Lap at the Shore at the Vermont Waterfront." Burlington Free Press, 28 Apr. 2022, www.burlingtonfreepress.com/story/news/2022/04/28/lake-champlain-flooding-liklihood-warmer-wetter-climate/9568231002/. Accessed 9 Nov. 2024.

Stickney, Michaela, et al. "Lake Champlain Basin Program: Working Together Today for Tomorrow." Lakes & Reservoirs: Research and Management, vol. 6, no. 3, 2001, pp. 217-23.

2018 State of the Lake and Ecosystem Indicators Report. Lake Champlain Basin Program, 2018, lcbp.org/sol18dev/wp-content/uploads/2018/06/2018-State-of-the-Lake‗web.pdf. Accessed 9 Nov. 2024.

Winslow, Mike. Lake Champlain: A Natural History. Lake Champlain Committee, 2008.