Lake Superior’s Global Impact
Lake Superior is the world’s largest freshwater lake by surface area and its significance on the globe can not be understated. As the northernmost and deepest of the five Great Lakes, researchers have determined that its water temperature affects the long-term hemispheric climate patterns. Additionally, it stores other relevant environmental metrics, such as average oxygen levels, which marks its considerable influence on the environment.
The lake was formed at the end of the last glacial period and by geologic standards is a relatively young lake at just 10,000 years. It occupies over 82,000 km2 and covers a major region of the Canadian/American border. It’s inflows include the Nipigon River, the Saint Louis River, and the Saint Marys River, with the longest being the St. Mary’s, at 183km. The lake runs approximately 350km from east to west and 350km across from north to south, making it the largest lake in North America.
Surface Temperature of Lake Superior
The surface water temperature of Lake Superior fluctuates from an average low of 35 Fahrenheit (1.67 Celsius) in winter to a high of around 75 Fahrenheit (24 Celsius) in summer. The water temperature has been known to rise to as much as 80 Fahrenheit (27 Celsius) in the late summer time when the sun is at its strongest. Of course, the temperature varies depending on the region and time of year, with the greatest fluctuations observed in the central region.
The coastal areas tend to experience a slightly warmer temperature than the northern or southern shore as they are more exposed to the sun. Also, the water has been known to reach a low cold temperature of below 0 Celsius during winter in some parts of the lake. During the coldest months, even with extreme cold temperatures, the lake takes time to cool down.
The influences of wind and solar radiation both play a role in the surface temperature of Lake Superior, but the weather patterns, especially in summer, primarily drive the water temperature. During the summer, strong winds from the south or southwest can cause the surface area to warm up more quickly than normal. Conversely, the surface temperature drops rapidly with a cold, northerly wind.
Effects of Abnormal Temperature Changes
Abnormal changes in temperature, either up or down, can have an adverse effect on the ecology of the lake, including flushing out beneficial nutrients from the water. In addition, the fish found in the lake, such as salmon and trout, as well as other animals rely on the food sources brought up from the depths.
Thus, when the temperature drops too low, the food supply can become scarce, leading to a lack of food for the inhabitants. Abnormal temperature increases can lead to the growth of undesirable algae and bacteria, resulting in the death of other marine life. Furthermore, the increased water temperature can also affect the balance of oxygen in the water, leading to conditions that are not suitable for sustaining life.
Impact on Local Economy
Lake Superior’s water temperature also affects the local economy. Cooler water temperatures during the summer time can cause a decrease in the tourist influx due to decreased swimming activities. Likewise, this can have a negative effect on economies that depend heavily on tourism. This can also lead to a decrease in local jobs within the service sector such as restaurants, hotels, or retail stores.
Inversely, warmer water temperatures can be beneficial for those who rely heavily on propagation of already established fish species such as salmon and trout, which can improve fishing activities for both recreation and sport purposes. This can lead to more tourism related to fishing, attracting more people to the area which can lead to job growth and increased revenue.
Monitoring Water Temperatures
Various organizations are responsible for regularly monitoring the water temperature of Lake Superior. This includes agencies such as the United States Geological Survey (USGS), Environment Canada and the United States Environmental Protection Agency (EPA). These organizations continuously collect data on the temperature and other related indicators in order to ensure the safe use of the lake for tourism, economic, and ecological purposes.
This often includes collecting real-time data on the temperature of the lake surface as well as real-time data on various other metrics such as dissolved oxygen levels, pH, salinity, algal concentration, and eutrophication. The data collected is then used to monitor and potentially predict climate change trends and other potential anomalies in the lake.
Factors That Affect Water Temperature
There are a wide variety of fluctuations that affect the surface temperature of Lake Superior. These include seasonal temperature changes as well as wind speed, humidity, and solar radiation. The lake can often take time to cool down since it dissolves heat slowly, making it useful in buffering low temperatures during the winter months.
Furthermore, the lake’s enormous size and shallowness when compared to its predecessors makes it especially sensitive to weather related changes. In addition to seasonal fluctuations, the rate of water flow is heavily affected by outflow from the lakes and small rivers, which in turn supply optimal temperature levels as per the season.
Effects of Water Temperature on Weather Patterns
As the highest of the Great Lakes and new research has indicated, Lake Superior’s temperature variations can affect weather patterns in North America. Studies demonstrated that higher temperatures from the lake can modify the local climate significantly and generate intense weather events such as the strong thunderstorms across the Midwest.
Additionally, the lake heat can also modify the metabolism of insects, as well as the reproduction cycle of aquatic plants, leading to abnormal changes in the food chain in the region. Crop production can be influenced too, as the warmer temperature of air associated with the lake influences the rate at which rain falls and the rate of evaporation.
What Causes Changes in Water Temperature?
Changes in the surface water temperature of Lake Superior are primarily caused by seasonal weather patterns and their associated winds and solar radiation. Other factors such as the water flow velocity, the upwelling or downwelling of water, and the amount of rainfall can also have an impact on the temperature. In addition, ocean currents, heat exchange between air and water, and wind-driven surface mixing can all impact the water temperature.
As a result, water temperature changes can be observed throughout the year in the surface and deeper areas of the lake. This continuous fluctuation in temperature contributes to the lake’s remarkable resilience, which has enabled life forms to survive for tens of thousands of years.
Influences on the Lake Superior Ecosystem
The changes in water temperature can also affect the lake’s ecosystem. For example, Lake Superior is home to diverse species including fish, plants, and amphibians, whose habitats are being challenged as the temperature change. The effects can be seen in numerous species, which have been observed shifting to offshore and deeper habitats to cope with the temperatures. Additionally, the biological activities of the lake and its organisms are affected with the changes in temperature, resulting in slower growth and possible decreases in wildlife populations.
The lake’s unusual combination of cool temperatures during the summer and warmer temperatures during winter gives Lake Superior many unique characteristics, unique to the Great Lakes. It’s physical location, size and seasonal characteristics make it an invaluable part of the Great Lakes system and its importance to the region cannot be overstated.
