Very well put, but there are other factors affecting the dissolved oxygen in Greenfield Lake that only worsen the root cause due to over-eutrophication that you described. The cities' use of chemicals to poison all of the oxygen producing submergent vegetation (both native and non-native varieties) has exponentially affected the amount of dissolved oxygen necessary to maintain aquatic life in an already stressed system. Although the submergent vegetation was completely eradicated last summer, it is evident that the emergent vegetation along the shoreline is now being sprayed. With surface water temperatures in the upper 80's to low 90's, essentially no fresh water flowing through the system and a heat wave, not the time to be spraying chemicals in the water. Lastly, I haven't seen the aereators working on any of my recent outings to the lake, and with them being solar powered, I assume they don't run at night anyway when the dissolved oxygen is at its' lowest and aereation is needed most.