Climate Change unleashes Lake Michigan’s Hot Water as it Bleeds down to its Bottom. Credit: CCO Public Domain
Greetings to you! Unfortunately, I have more sobering news on the subject of Climate Change. According to a recent report published a few days ago by the National Oceanic and Atmospheric Administration [NOAA], “Water hundreds of feet below the surface of Lake Michigan is warming, especially in winter. The warming could change the seasonal patterns of the lake – and alter a way of life for ecosystems and industry alike.”
It has long been known that rising surface temperatures and decreasing ice cover is the result of “human activity, which spurs climate change.”
Craig Stow, NOAA Great Lakes Environmental Research Laboratory scientist and author of this study explains, “These changes may seem very small, a couple tenths of a degree per decade, but this has been going on for several decades now, perhaps longer than is reflected in our monitoring. The lakes have been changing, ever since they were formed. But when they change fast it means humans have to adapt to the changes that occur. And if we don’t monitor for them we run the risk of being caught by surprise.”
Stow continued and said, “The first-of-its-kind look at deep water warming fills in another gap in climate change research, revealing what’s happening below Lake Michigan’s surface. The overall warming, ice loss and shrinking winters could lead to long-term shifts, altering the lake’s food web and sending fisheries toward uncharted territory. Some of the surfaces of the world’s largest lakes are warming faster than ocean and air temperatures. We’ve known for a while now based on surface temperatures—not just in Lake Michigan but smaller lakes and large lakes worldwide—that the surface temperatures seem to be increasing.”
Lake Michigan’s Deep Waters are Warming at Approximately .06 degrees Celsius per decade!
Scientists report that, “Lake Michigan surface temperatures are estimated to be warming at a rate of as much as a third to a fourth of a degree Celsius per decade.”
However, towards the lake bottom of 460 feet below the surface is sparse. “Deep water research had previously relied on translating surface data or limited observations. So starting in 1990, researchers turned to a string of thermometers floating vertically in southern Lake Michigan to gather measurements. NOAA Great Lakes Environmental Research Laboratory scientists looked at 30 years of measurements, some hourly, to track seasonal patterns far below the surface.”
The study for this blog was published in Nature Communications. It says Lake Michigan is, “likely the world’s only large lake with this type of long-term observations of water temperatures at depth. In deeper water, warming is estimated to be as much as .06 degrees Celsius per decade.”
Stow said,“This is a big lake and that’s a lot of water. That’s a lot of change. Warming so far below the surface wasn’t necessarily a surprise, but it’s hard to know what’s happening without data. It could have been that we’d only see an effect down in the first 30 or 40 meters, but we saw it down really far.”
The study says, “Lakes can serve as climate change sentinels and deep water measurements can be particularly important because they provide a climate memory.”
“What we can see from this data is a reflection of larger scale and longer-term processes,” Stow said. “They’re not obscured by the noise that might occur from a couple very warm or a couple very cold years.”
“The water’s warming winters reflect rising surface temperatures and prolonged summers. Some of the most pronounced jumps in winter temperatures are occurring near the Great Lakes. Records dating back to 1973 show maximum ice coverage across the Great Lakes is declining 5% per decade; Lake Michigan’s ice coverage decline is about 3.6%.”
Stow continued and said, “Lake Michigan is dimictic, meaning there’s a top-to-bottom mix of the water column twice a year. With warmer surface temperatures, the fall mixing cycle is starting later, leading to a shortened cooling period for deep waters and a longer summer period without mixing. The organisms that live there, the plankton and the fish, are used to the lake the way it was. They evolved over thousands of years to take advantage of those systems that mixed twice a year.”
Stow explained, “If the lake changes to warm monomictic, mixing once a year, it would signal fundamental change. And the other thing you have to remember is this is not the only thing going on.” He noted, “changes spurred by invasive zebra and quagga mussels. All of that’s happening at the same time.”
Stow’s study reported, “…examples of what’s happened in other large lakes. Thermal change can mix up the food web and lead to the proliferation of invasive species. Longer periods when the lake is not mixing can exacerbate low-oxygen conditions. In Lake Erie, for example, low oxygen has contributed to fish die-offs.”
Stow concluded and said, “In all, the consequences of changes in subsurface water temperatures will result in a profound shift in lake ecology. Without high-frequency long-term monitoring of subsurface waters, we will be blind to the impacts of climate change on most of Earth’s fresh surface water.
Good News! There is a new Kobee Manatee® Children’s Educational Picture Book coming out in September 2021. It is titled, Kobee Manatee® The Great Blue Hole Hazard, which teaches children all about climate change with Dr. Tracy Fanara.
Kobee Manatee® The Great Blue Hole Hazard, focuses on climate change and plastic pollution. This title will be released in September 2021!
Keep watching for more updates and stay tuned for more of my blogs!
If you see any sick or injured manatees, please call the Florida Fish and Wildlife Conservation Commission at: 1-888-404-3922 (FWCC). They are the folks who are responsible for rescuing us in Florida.
Here’s the Save the Manatee Club link to learn more about us manatees …
Here’s a cool link for you to learn more about how we’re rescued and brought into rehabilitation …
~ Kobee Manatee