ABSTRACT
Excessive nutrient enrichment (eutrophication) and organic loading problems occur in many coastal ecosystems worldwide and invariably are coupled to a variety of anthropogenic activities. Estuarine and coastal marine waters often receive large amounts of nutrients from both point and nonpoint sources, including industrial and municipal wastewaters, dredged material, sewage sludge, agricultural and urban runoff, ground water seepage, and atmospheric deposition. Eutrophication also can create unfavorable conditions for submerged aquatic vegetation. Shallow coastal seas that are poorly flushed appear to be the systems most susceptible to dissolved oxygen depletion. In estuarine and coastal marine waters of the temperate zone, nitrogen is the element usually limiting to primary production. The input of organic carbon has been linked to eutrophication problems and decreased dissolved oxygen levels in estuarine and coastal marine waters. Eutrophication leading to anoxic/hypoxic events has now been documented in the coastal waters of many other countries.
