2014 photo of a rather the rather uniform and clear waters of the Detroit River, with a cool fog bank for effect.
https://www.cbsnews.com/amp/detroit/...ts-belle-isle/
Rivière Détroit ISS, The Detroit River is a bit of a synonym but it sounds fine to my English speaking ears so we’ll just leave that. Not a knock against Ontario pointing out the odd state the river is in as around the Great Lakes but agricultural practices. The story of the Maumee River in Toledo is the canary in the coal mine for other major rivers in ag heavy areas. The Saginaw & Fox jump to mind as they empty into shallow waters Saginaw Bay & Green Bay respectively and both bays have become much greener as of late. The rise of consented animal feed lots and the business of overselling the manure especially in a liquid form has been pointed to by a PBS documentary as the key factor to the massive algae blooms in western Lake Erie, watch “The Erie Situation” if you can find it.
2018 view of a two toned Detroit River a situation that seems to becoming more and more common.
https://www.alamy.com/aerial-of-the-...218185135.html
2022 dry summer highlights what is usually only a slight two tone when noticeable.
https://earthobservatory.nasa.gov/im...-of-the-strait
Certainly there are other causes of concern for the health of Great Lakes waters, suburban lawn fertilizer likely plays a role in the mucking of St Clair shoreline in still harbors around the Clinton River Delta. The algae blooms in the Apostle Islands of Superior are much more concerning and harder to trace but I do have a theory.
The Ashland Wisconsin area isn’t a large center of agriculture yet there is not an insignificant amount. Certain factors are however in place in the White River, Fish & Wittlesey Creeks which in my must be where the nitrogen rich water is coming from. They include wooded floodplain & some of the healthiest and most pristine looking wetland deltas I’ve ever seen. So there is plenty of natural filtration going on for agricultural runoff over relatively small basin. So what’s going on?
A few things are happening in my mind to create a baffling situation where an algae bloom has begun to happen during the summer in an area of Lake Superior with normally crystal clear water. First is what I mentioned before while the Ashland area lacks intensive agriculture Wisconsin is famous for its dairy industry, the waste product ie manure is sold to farmers as fertilizer from concentrated animal feed lots.
Best practices are not employed when using manure especially liquid manure over farm fields as fertilizer. While using organic fertilizer as opposed to chemical fertilizer or at least leaning on organic is preferable how, in what form, when & quantity becomes a problem.
I’ve only heard statistics from Ohio that concentrated animal feed lots often have minimal inspections to determine if they are industrial scale or “mom ‘n pop”. Often with only a handful of inspectors in the state farmers can sell off a certain number of animals to fit into the smaller less regulated category knowing when inspecting is coming. This process creates tons of manure that is sold off as fertilizer and farmers are encouraged and told they need to use much more than is actually needed.
Using liquid manure on fields during the spring planting season leaves then especially vulnerable heavy rains washing away much of the nitrogen rich material. A dry form of organic fertilizer would be much more difficult to wash away yet it requires more time and or processing. The income source created for concentrated animal feed lots by eliminating a costly to clean waste product is an important part of the financial structure of the feed lot system.
Yet all this by itself probably wouldn’t be enough to create algae blooms in the region due to the virile health of flood plains and coastal wetlands. The local geography and global warming create the petri dish for the blooms to become harmful. Chequamegon Bay is shallow sandy and sheltered by a sand spit while all major and minor catchments have wetland outflow into. Google Maps will show a slight cloud of slit flowing north into the Apostle Islands from the otherwise normally clear and clean bay waters. The Apostle Islands also form a shallow sheltered zone next to two bays with agricultural runoff.
I can’t put this all on the Ashland area although it makes for a great case study for pin pointing sources. Duluth & Superior have a not insignificant amount of farm land as well as urban runoff and a large chemical industry in Superior. 2018 the year of the explosion and fire was also the year of the great floods around Lake Superior whether or not any errant chemical runoff even got into Lake Superior is above my pay grade and as well if it would have any impact on the recent algae bloom conditions.
My point is in one of the cleanest bodies of water in the United States and quite a cold one is showing signs of stress in its warm shallow sections. This should be particularly helpful for pinpointing exactly what is causing water quality problems in much more urban and agriculture heavy areas.
Here’s a view of the results of the destructive 2018 floods that hit western Lake Superior. Note the unhealthy murkey green floating up the east and west sides of the peninsula that the Apostle Islands jut out of. Certainly the conditions in Apostle Islands National Park are at a more nuisance situation than Western Lake Erie, Saginaw Bay, Green Bay, Lakes St Clair & Winnebago. Human activities can certainly create similar problems leaky septic systems during heavy rain events have caused mentoring for ecoli and algae in Keweenaw Bay Michigan another shallow warm Superior bay.
https://wiscontext.org/washed-away-n...anging-climate
***I chose a different smaller photo for the above picture and discovered the big plume coming from the Ontonagon River. This throws a wrench into my argument extrapolating the Lake Erie results and applying them to applicable shallow warm (get above 70F in the summer) bays on Superior. If I had to take a swing at this leaky septic tanks adding nitrogen during the great flood. Michigan is the only state in the country without a unified septic code & the Upper Peninsula has particular difficulty repairing and rebuilding septic systems Ive heard. The hard rocky ground and sometimes only 6 month to conduct repairs makes the costs rise in an area with a generally low avarage income. Still Ontonogon has a population of only 2k year round residents there is cynobacteria in Lake Superior it just doesn’t bloom under normal cold conditions. The flood of warm river water may have been a good breeding ground for naturally occurring algae to bloom, it’s likely we are super charging the algae yet global warming is contributing significantly as well. Superior is one of the fastest warming bodies of water on the planet.
Thunder Bay Ontario has had algae blooms as well an area with very minimal farming which points to human and urban runoff being able to cause these conditions as well. Here’s a 2019 Great Lakes Now article on the appearance of blooms in Superior.
https://www.greatlakesnow.org/2021/0...r-algae-bloom/