Changing Climate
The bottom of Lake Superior, the largest, deepest and coldest of the Great Lakes, is home to an environment of shifting mineral concentrations, shifting temperatures and changing aquatic life. As climate change brings higher temperatures, more rain and new shorelines, the bottom of the lake evolves constantly.
The lake’s depth varies from 120 to 483 feet and the temperature varies depending on location and time of year. Warmer temperatures at the surface layers cause inert, energy-poor bottom waters to mix with cooler waters in the top. This mixing creates a stratified lake, with distinct layers that vary in temperature, salinity and nutrient content.
Over the last century, Lake Superior and many of the Great Lakes have seen dramatic changes due to human activity, with increased runoff from agriculture and increased industrial activity leading to more pollutants. As global temperatures rise, more fresh water from higher precipitation and increasing water temperatures further disrupt the environment.
These changes impact the lake lake’s bottom, which is home to a range of species, including gamefish, mollusks, crustaceans, amphibians and insects. These aquatic creatures thrive in unique conditions, such as salinity, water temperature and nutrient concentrations, which are all influenced by climate change.
The number of invasive species has increased as well, impacting native species’ ability to survive and compete for food. For example, round goby, an invasive species from Europe, have become the most common fish in Lake Superior, out-competing native species.
Economic Impact
The health of the bottom of Lake Superior contributes to the health of the region’s economy. Its fisheries, shipping lanes, recreational opportunities and resources have made the Great Lakes region a hub for commerce and travel. The direct economic impacts of aquaculture, fisheries, and sport and recreational fishing are estimated to make up most of the region’s directly linked economic activity.
The health of Lake Superior is highly connected to the health of the other Great Lakes and the region as a whole. Any changes to the lake’s health, whether caused by climate change or the spread of invasive species, can have economic repercussions.
Michigan State University’s Water Resources Institute estimates that more than 60 percent of precipitation from the eastern basin of Lake Superior drains to the other Great Lakes. Changes in the lake’s bottom, caused by a variety of factors, can cascade from Lake Superior to other lakes downstream.
Increased runoff from agriculture and construction, for example, can lead to aquatic weed control problems, decrease water clarity and contaminate fishing spots. These changes can lead to economic losses in areas where recreational fishing and tourism are central to the economy.
Water Quality
The water quality of Lake Superior has always been higher than in other Great Lakes, due to its large size and northern location. But recent changes pose some challenges. Nutrient-rich waters from increased runoff from agricultural land and the construction of dams are among the sources of water pollution, causing the growth of cyanobacteria and the resulting increase in harmful algal blooms.
Excess nutrients further disrupt the lake’s ecosystem, causing changes in water quality, acidification and impacts on aquatic life such as fish. These changes also have implications for human health and safety, as the contaminated water creates a risk of exposure to harmful algal toxins.
Lake Superior’s vulnerable shorelines are especially affected. As waters rise, pollutants concentrate on coastal lands, affecting the quality of drinking water and leading to increased erosion and flooding.
Mitigating the Effects
The federal government and states throughout the region are taking steps to monitor the changing aquatic environment and identify solutions to mitigate the effects of climate change.
Great Lakes states have adopted laws and policies addressing water quality, biodiversity and ecosystem health. These measures have helped ensure that communities along the shorelines of Lake Superior have access to clean water and an environment conducive to recreational activities.
In addition, efforts by both government and non-profit organizations are being made to reduce the impact of development and runoff from agricultural lands. Innovative practices, such as conservation tillage, reducing fertilizer use, and increasing wetland and riparian habitat, are having positive impacts on water quality and other aquatic ecosystems.
Future Outlook
Given current climate change predictions, Lake Superior is likely to experience changes in water level, precipitation and temperatures in the future, leading to further changes in the lake’s bottom. These shifts in the lake’s environment can have both positive and negative impacts.
Researchers are looking at potential impacts to fish populations and other aquatic life, as well as lake-wide food webs and nutrient cycles, to get a better idea of how the lake will be affected in the future. As the understanding of Lake Superior’s changing environment increases, researchers can better develop strategies to protect and manage it.
In addition to these efforts, communities throughout the Great Lakes Basin face a challenge to balance the needs of a diverse set of stakeholders while preserving the natural environment. Government and non-governmental agencies are working together to ensure that resources are used responsibly and to meet the needs of all users.
Local Efforts
Communities along the Great Lakes recognize the importance of maintaining and improving the health of Lake Superior and take action to do so. Locally-based efforts focus on informing citizens about the health of the lake, reducing pollution and encouraging conservation.
Establishing a regional management plan is an important part of this effort. In the United States, the Great Lakes Restoration Initiative involves multiple agencies and citizen input in an effort to address local problems related to water quality and wildlife.
In addition to modernizing infrastructure, the initiative aims to restore natural systems and protect the environment by mapping land cover and controlling pollutants. These efforts take into account the complex interactions between land and water, and involve federal, state, tribal and local governments as well as other entities collaborating to protectLake Superior.
Creating Awareness
Creating awareness of climate change and its impacts on the environment is one of the most important efforts that can be taken to protect Lake Superior and other Great Lakes. Social media, educational programs and media campaigns can help raise awareness and encourage people to embrace conservation practices.
Organizations like the Freshwater Sustainability Institute work to increase public awareness of aquatic issues and educate citizens on how to make a difference in their own lives. By engaging citizens in aquatic conservation and management, these and other groups hope to create a network of informed and committed lake-goers who can make a difference.
Communities throughout the region are also engaging in activities that promote a balanced use of resources and a better understanding of the environment. Events like beach cleanups, engaging trails and educational programs further help to get people involved and concerned about the future of Lake Superior.
