The Great Lakes. You know their names – Superior, Michigan, Huron, Erie and Ontario, plus their connecting channels form the largest fresh surface water system on Earth! This system is a source of drinking water for more than 40 million Americans and Canadians. The system covers more than 94,000 square miles and holds an estimated six quadrillion gallons of water which constitutes approximately one-fifth of the world’s fresh water supply and nine tenths of the fresh water supply in the United States.
Lake Superior is the largest of the Great Lakes and has the largest surface area of any freshwater lake in the world. Lake Superior is also the coldest, deepest, and most pristine of the Great Lakes with an average depth of nearly 500 feet and has some of the coldest water and clearest visibility in the system, averaging 27 feet, and as deep as 90-100 feet in some parts of the lake. Lake Superior is also known for its shipwrecks including the SS Edmund Fitzgerald, an American Great Lakes freighter that sank in a hurricane Westwind killing the entire crew, as penned in a song written by Gordon Lightfoot.
But there appears to bean alarming trend of algal blooms within the last 12 years. “Algal blooms occur when harmful algae start multiplying out of control in a body of water. Excess nutrients, warm temperatures, and sunlight all contribute to the phenomenon.” In Florida, we know a lot about algae blooms, and it is not something to brag about. But our water temperatures are a lot higher than Lake Superior, so what is happening? “ In the past, there were no recorded algal blooms at Lake Superior. But in 2012, The Conversation reported that its southern shore experienced a bloom, and more have occurred every year since 2016. Worse, blooms started on the northern shore in 2019.”
Can you guess what is causing these algal blooms? You got it – humans. “Heat-trapping air pollution has warmed the planet and made Lake Superior the fastest-warming lake in the world, according to The Conversation — reducing the time it's covered in ice by two months in the last 150 years. In 2024, only 12% of its surface froze, about one-fifth of the ice cover in a typical winter.”
In addition, the lake and its surrounding areas are now taking on more nutrient-rich runoff from agriculture and urban areas, and “the algae in these blooms is actually a type of bacteria called cyanobacteria.”
But what is so bad about algal blooms? “Not only does the cyanobacteria cloud the water and block sunlight from other plants, but in the right conditions, it can also produce toxins that harm people and the environment.” “At best, an algal bloom in a body of water that people drink from causes an unpleasant taste and smell; at worst, it interferes with water treatment processes, causes digestive issues and liver damage in humans, and can kill pets and livestock.” In Florida we have “Red Tides” (harmful algae blooms) from huge amounts of algae blooms turning the water red. The algae can kill thousands of fish and other marine species, make shellfish dangerous to eat, and make the surrounding air difficult for humans and animals to breathe.
If you notice unusually murky, greenish waters, report it to any local environmental agencies or officials. But in the end analysis, it’s up to us human beings to deal with the causes of these algae blooms by using less fertilizer and stop dumping harmful chemicals into the water. Most of all, we must join in reducing the harmful emissions that pollute our air and heat up our planet. This isn’t an easy task because it will take hundreds of millions of people to begin turning things around for Mother Earth.
Sources:
https://www.thecooldown.com/outdoors/lake-superior-algal-blooms-great-lakes/
https://theconversation.com/climate-change-is-causing-algal-blooms-in-lake-superior-for-the-first-time-in-history-233515
https://www.thecooldown.com/green-home/lacamas-shores-bloom-algae-bloom-hoa/
