Why is Lake Superior Brown?
Known for its majestic beauty and famous for the endless supply of fish, Lake Superior, the world’s largest freshwater lake, has an unmistakable brownish hue. Locals and visitors to the area often ask, why is the lake water so brown?
One explanation is the presence of tannins, also known as humic acids, which are released into the lake due to decaying vegetation. The tannins bind to suspended particles and sediment, turning Lake Superior’s water dark brown. Leaf litter, soil runoff, and other plant matter in the lake further contribute to the dark hue in the water.
Sometimes, the brownish water comes from sources outside of the lake. When strong winds blow from the south, they bring with them plenty of sediment runoff from the rivers and streams of the many farms surrounding the lake. This sediment runoff also causes the water to become discolored.
In addition to discoloration, Lake Superior’s brown water can have a negative impact on the lake’s ecology. The darker water absorbs more sunlight, meaning the lake waters don’t get as much oxygen. This can create an undesirable environment for certain fish and other aquatic life.
Local experts suggest that the dense vegetation surrounding Lake Superior creates an environment with a large population of animals whose waste can find its way into the lake and contaminate the water. Many of these animals excrete tannins, which then mix with the lake’s waters and make it brown. When the lake levels are low, the plant debris and sediment are more concentrated, causing even further discoloration of the Lake Superior’s waters.
Finally, researchers believe that the mineral content of the lake plays a role in the brownish hue of the water. According to their research, the iron, copper, and manganese found naturally in Lake Superior’s currents react with other particles in the lake, resulting in a murky brown color that is typical of the lake.
Natural Sources
Sediment runoff from nearby rivers and streams is a major contributor to the discoloration of Lake Superior’s water. This sediment is made up of soil particles, minerals, and organic matter that washes into the lake from the surrounding land. Soil runoff is often the most concentrated near waterways and agricultural areas, which is why it is such a significant contributor to the brownish water.
Another source of the brownish water is the decaying vegetation that finds its way into the lake. During the summer months, when the lake levels are higher, the amount of leaf litter, dead plants, and other organic matter increases dramatically. As this plant matter decomposes, it releases tannins and humic acids that bind to other particles and create a murky brown color.
The chemical composition of the lake water also impacts the discoloration. Lake Superior’s water contains trace amounts of iron, copper, and manganese, which, over time, can react with other substances in the lake and cause a brownish hue.
Human Sources
Discoloration of Lake Superior’s water can also be caused by human activity. Excess nutrients, such as nitrogen and phosphorus from fertilizer runoff, can find their way into the lake and create an imbalance in the water’s chemistry. This can result in the growth of algae and other aquatic plants, which can then release tannins and cause a brownish color in the lake.
Industrial and agricultural runoff is another major contributor to the brownish hue of Lake Superior’s waters. Runoff from industrial sites often contains heavy metals and other chemicals that can pollute the lake. Similarly, when fertilizers are used in and around agricultural areas, they can wash into the lake and affect its chemical composition.
The effects of human contamination can be felt long after the initial contamination. The tannins and other pollutants released from these activities can take a long time to break down and will linger in the lake for much longer than the pollutants that are released from natural sources.
Effects of Brown Water
The discoloration of Lake Superior’s water can have a significant effect on the lake’s ecology. The darker the water, the more sunlight is absorbed, meaning the lake waters don’t get as much oxygen. This can create an undesirable environment for certain fish and other aquatic life.
Another consequence of the discolored water is the reduction in visibility. When the water is murky and discolored, it is harder for aquarists to monitor and observe the health of the lake’s inhabitants. Furthermore, the brownish water can also have a negative impact on recreational activities, such as boating and fishing, which rely on a clear view of the lake.
The discoloration of the lake can also affect the ability of aquatic plants to photosynthesize. When the lake’s waters are murky and dark, photosynthesis is hindered, leading to greater levels of algae and other aquatic plants in the lake. These aquatic plants can also clog up boats, water intakes, and irrigation systems, which can then put additional stress on the local economy.
Conservation Efforts
Fortunately, there are several measures being taken to help protect Lake Superior from becoming overly brown. Many of these involve educating the public about the importance of maintaining a healthy lake ecosystem and how even small changes can have a large impact on the lake’s water quality.
Local governments and conservation groups are also working to reduce the amount of sediment and nutrient runoff entering the lake through erosion control measures, more efficient irrigation systems, and better regulation of agricultural activities. The use of artificial wetlands is also becoming more common, as they can help to filter out pollutants before they reach the lake.
Other methods being used to protect Lake Superior from discoloration include the implementation of stricter regulations on industrial waste, stricter water quality monitoring, and the removal of invasive species that can have a negative impact on the lake’s ecology.
Future of Lake Superior
The efforts of local communities and conservation groups have made a positive impact on the health of Lake Superior over the years. Although the lake’s waters still have a brownish hue and sometimes are affected by sediment and nutrient runoff, overall, the lake’s water quality has been improving. With continued conservation efforts, it is likely that Lake Superior will remain one of the world’s most beautiful and pristine bodies of freshwater.
Despite its current issues with discoloration, Lake Superior remains an incredible source of beauty and life. Its vast array of fish, interesting plants, and scenic views make it a popular destination for locals and tourists alike. Whether you are swimming in its waters or simply taking in its breathtaking views, Lake Superior is a sight to behold.
