Are you saying the farmer's fertilizer run off is the cause of the algal blooms? Are they telling the farmers this information?
Nutrients obviously drive the algal blooms but other factors come into play as well.
Total Phosphorous that is delivered to Lake Erie has been and continues to decline. This is due to improvements in the sewage treatment plants, and the erosion control and conservation practices that have been applied to the watershed over the last 30 years. However, soluble phosphorous (or dissolved phosphorous) delivered to the Lake has been increasing since 1995. Scientists right now are trying to determine and pinpoint the cause of this increase.
At the same time, invasive species of zebra and quagga mussels have invaded the lake. Some scientists believe these species are aggravating the algal blooms because the mussels filter the phosphorous and excrete it into pellets that stay in the near shore areas of the lake. The theory is that this concentrates the phosphorous in the lake in the shallow warmer waters accelerating the algae blooms.
There have also been changes in the types of algae in recent years, as well as warming of temperatures which accelerate growth.
All of these factors are combining to result in a changing situation in the lake that is being studied to find solution to the increasing problems. USDA NRCS, local Soil and Water Conservation Districts, OSU Extension, and private organizations are all working diligently to tell the story to farmers and homeowners in the watershed and to promote the conservation practices on the land that will mitigate excessive nutrient runoff.
Steve Davis, USDA – NRCS