eutrophication

[noun]

A process of excessive plant growth in a water body (usually phytoplankton) in response to an influx of nutrients. The excessive growth prevents sunlight from reaching other plants below the water’s surface, which in turn prevents those plants from photosynthesizing. This change reduces the amount of dissolved oxygen available to the organisms living in the water body, causing suffocation.

While the increase in nutrients that causes eutrophication can occur as a result of natural phenomena (e.g., a mudslide or atmospheric deposition), excess nutrients typically come from human practices like farming (fertilizer runoff). Phosphorus and nitrogen are the main nutrients involved in eutrophication of water bodies.