Eutrophication is a natural process that occurs in an
aging lake or pond as that body of water gradually builds
up its concentration of plant nutrients. Artificial or cultural
eutrophication occurs when human activity introduces
increased amounts of these nutrients, which speed up plant
growth and eventually choke the lake of all of its animal
life. Therefore, lake affected by high levels of artificial
eutrophication will have high nutrient levels, large
phytoplankton populations and low oxygen levels at depth.