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whitetailhunter
Guest
This is a very complex issue which nobody, including the MNR has concrete answers to. I’m not saying I have all the answers but I’ll take another stab at clarification.
The link I gave you only addresses part of the equation in what I said but the information comes from many documented sources on the issue of phosphorous levels in Lake Erie. This is an issue that is not easily answered by science nor has government agencies found a suitable solution to it as most reports are not based on proven fact but theory based on studies and differing opinions. The point I was trying to make was that high levels from phosphate detergents are no longer relevant because it’s proven that’s no longer the case. Phosphorus is an essential element for all organisms and is often the limiting factor for aquatic plant growth in the Great Lakes. Although phosphorus is found naturally in tributaries and run-off waters, the historical problems caused by elevated levels have predominately originated from man made sources. Sewage treatment plant effluent, agricultural runoff and industrial processes have released large amounts of phosphorus into the Lakes. Strong efforts begun in the 1970’s to reduce phosphorous loadings have been successful and in also reducing nutrient concentrations in the Lakes, although high concentrations still occur locally in some embayments and harbours. Phosphorus loads have decreased in part due to the removal of phosphorus from detergents, changes in agricultural practices (e.g., conservation tillage and integrated crop management), and improvements made to sewage treatment plants and sewer systems. It’s actually been praised as an astonishing success story.
However, I realize there are still high concentrations in the western basin where most algae blooms occur during the summer runoffs from fields and the shallow water of Erie only compounds the problem. Some now have good reason to believe that algae blooms are a natural occurrence in the western basin and probably have always been but only came to the forefront when phosphorous overloads from the sources mentioned above entered the picture. Although for the most part they have solved the main problem of extremely high phosphorous throughout the Great Lakes it also created a new one where the levels in the eastern basin have dropped to levels where both food web dynamics and nutrient cycling have been greatly altered. This is where zebra muscles have introduced a deadly mix into the equation by filtering too much algae from the water causing phosphorous to drop dramatically. The MNR and the DNR jointly are seriously considering raising the phosphorous levels in the eastern basin but want many more studies done to determine whether it would just become another example of solving one problem but creating another in the process.
