Prior to human interference, this was, and continues to be, a very slow natural process in which nutrients, especially phosphorus compounds, accumulate in water bodies. These nutrients derive from degradation and solution of minerals in rocks and by the effect of lichens, mosses and fungi actively scavenging nutrients from rocks. Anthropogenic eutrophication is often a much more rapid process in which nutrients are added to a water body from any of a wide variety of polluting inputs including sewage treatment, industrial waste and farming practices. The visible effect of eutrophication is often nuisance algal blooms that can cause substantial ecological degradation in the water body and in the streams flowing from that water body. This process may result in oxygen depletion of the water body after the bacterial degradation of the algae.