Since the 1990s, dissolved phosphorus has gone up dramatically from agricultural runoff, and between the years of 1981 and 2008, the ratio between agricultural phosphorus and municipal phosphorus has been 3-to-1.
"The spring loads of 2011 were the largest we'd ever seen since we began monitoring in 1975," said Baker. That increase undermined the successes in reducing municipal phosphorus through an agreement with Canada and with amendments to the Great Lakes Water Quality Agreement.
Ironically, no-till agriculture, a practice designed to improve the environment by not degrading the quality of the soil, has helped facilitate the carriage of nitrogen to the lake. Phosphorus fertilizer lies on top of the soil instead of being dug into it.
Ohio bill to regulate fertilizer in the works
The project to study algal blooms and climate change came before the record algal bloom, said Allison Steiner, an atmospheric scientist at the University of Michigan and a co-author of the study.
"We really were very well poised to address the comprehensive nature of this problem," said Steiner. The group included a geospatial statistician, a water runoff modeler and economists who study land-use change.
Despite the gloomy future for Lake Erie's waters, there is room for mutually beneficial solutions to mitigate the problem, said Michalak. Washing phosphorus out with the rain is not only unhealthy for the lake, but a waste of money for farmers, so efforts to curb runoff would help both the environment and agricultural economy.
State agencies in Ohio are also seeking legislative solutions to better control agricultural runoff, said Logan. A bill has been drafted that would revise agricultural pollution laws to authorize the director of the Department of Natural Resources to designate certain watersheds in "distress," which would require the implementation of a watershed management plan. It would also require farmers who apply fertilizer to be certified by the state Agriculture Department.
Although most of the phosphorus runoff comes from crop fields, Steiner doesn't believe that reducing fertilizer is the best solution to the problem.
"I think that's an easy conclusion to draw," she said. "But the problem is much more complicated than that."
What's needed, Steiner said, is better communication to farmers about changes in rainfall and a better understanding of the adaptation measures.
Michalak of the Carnegie Institution agrees.
"One of the take-home messages is that this is a complex system," Michalak said. "Being too myopic and looking at one factor is clearly not the full story."
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500