By: Mark Kaminski
Summary. According to the EPA, Lake Superior contains over 2,900 cubic miles of fresh water. Containing 10% of the earth's fresh water, Lake Superior is the largest lake, by surface area, in the world. This lake was once thought to be "immune" to harmful blue-green algal blooms, but the last decade has shown otherwise. A protective characteristic of lake superior is its clean cold waters, since blue-green algae normally thrive in warm, nutrient dense waters. A fundamental shift in the waters of Lake Superior has recently allowed this algal to form. Since 2012, several algal blooms have been reported, with the largest bloom occurring in 2012 and 2018. The blue-green algal forms vast clusters of cyanobacteria that survive on nutrient run off and sunlight. The blooms have been described as a chalk-green color and can produce toxins that have been linked to the deaths of livestock and pets. Climate change can be linked to the rising water temperatures and the increase in nutrient run off. Region wide warming has caused a sufficient decrease on the Lake's ice cover during the winter and warmer surface waters during the summer. In fact, a joint study headed by the National Aeronautics and Space Administration reported that Lake Superior is warming at the fastest rate. In addition, surface water temperatures have increased 5 degrees Fahrenheit over the last 30 years. According to the National Oceanic and Atmospheric Administration, Climate change has also caused an increase in precipitation intensity by 40%, in the region. With larger, more violent storms there has been an uptick in erosion, ultimately leading to more phosphorous running off into the lake. This phosphorous is thus one of the main food sources for the algal. These blooms can lead to widespread problems in human infrastructure, in addition to, devastating damage to ecosystems. Blocking sunlight, degrading water quality, and depleting dissolved oxygen levels can choke out the local aquatic ecosystems causing ripples down the food chain. This in turn can hurt the major fishing industries and drive away tourist due to the unsettling smell and color. The blooms can also damage anything that may be consuming water from the lake. For example, in 2014 a bloom in Lake Erie forced the city of Toledo to shut off water intake from the lake because the city could not properly treat the water. Overall, the blooms found in Superior have not yet reached disaster levels, but it is feared that the lake is at a tipping point. In December 2020, The International Joint Commission between the United States and Canada stated that blooms in Lake Superior are expected to worsen, and a joint effort is needed to maintain adequate water quality of the Great Lakes.
Why we should care? This topic is important because toxic algal blooms are now found in one of the worlds largest lakes. In a single decade algal blooms went from being impossible to a yearly occurrence in Lake Superior.
I found this article interesting because it is dated back in 2015, just three years after the first algal bloom was reported in Lake Superior. It also reiterated the fact that Lake Superior was warming at the fastest pace out of all the great lakes. The article focuses more on the other Great Lakes, but it does a great job outlining some of the devastation that these algal blooms can and have caused. The article also mentions that these algal blooms could cause “dead zones” which would result in more methane being released into the atmosphere, leading to more climate change. One of the most chilling things mentioned in the article is the very last sentence where Donald Uzarski, of Central Michigan University is quoted saying “…small change in water temperature produces a domino effect…”, this domino effect that just six years later we are experiencing.
Science in Action.
Holly Wellward Kelly is a Senior Research Technician and Aquatic Ecologist at the University of Minnesota Duluth.
Holly Wellward Kelly is an Aquatic Ecologist who has studied everything from costal wetlands to the impact of pharmaceuticals on aquatic ecosystems. Currently she is working on monitoring the phytoplankton communities in the Great Lakes and working with aquatic invasive species. This is relevant to the Algal blooms on Lake Superior because these blooms impact aquatic ecosystems and degrade the water quality. This research is also relevant because these algal blooms are not occuring because of one factor but a verity of reasons. Kelly also has a unique perspective on this topic because Duluth Minnesota is located right on Lake Superior.