An ongoing concern is that nutrient overloading from fertilizers, human and animal waste, known as eutrophication, in which additional nitrogen and phosphorus enter the lake, will cause plant life to "run wild and multiply like crazy". Since there are fewer wetlands to filter nutrients, as well as greater channelization of waterways, nutrients in water can cause algal blooms to sprout as well as "low-oxygen dead zones" in a complex interaction of natural forces. As of the 2010s, much of the phosphorus in the lake comes from fertilizer applied to no-till soybean and corn fields but washed into streams by heavy rains. The algal blooms result from growth of "Microcystis", a toxic blue-green algae that the zebra mussels, which infest the lake, will not eat.