Eutrophication syndromes
Eutrophication was first evident in lakes and rivers as they became choked with excessive growth of rooted plants and floating algal scums, prompting intense study in the 1960's-70's and culminating in the scientific basis for banning phosphate detergents (a major source of P, the most frequent culprit in eutrophication of lakes) and upgrading sewage treatment to reduce wastewater N and P discharges to inland waters. Symptoms of eutrophication in estuaries and other coastal marine ecosystems (where N is the most frequent contributor to eutrophication) were clearly evident by the 1980's, as human activities doubled the transport of N and tripled the transport of P from Earth's land surface to its oceans. Eutrophication has emerged as a key human stressor on the world's coastal ecosystems.