The algal bloom in Lake Erie is particularly bad this year, thanks to a combination of agricultural runoff, sunlight, and warm water. The result, as seen by NASA’s Landsat 8, is the Great Lakes turning slowly green.
Algal bloom peaks in September, but the level is already high, and rising. Algae can make drinking water unsafe, but public water is reportedly still ok for human consumption.
[NASA]
Image credit: NASA