NOAA 2000-055
Contact: Connie Barclay


Conditions in most of the nation's estuaries are expected to worsen by 2020, according to a report released today by NOAA's National Ocean Service. The report, "National Estuarine Eutrophication Assessment: Effects of Nutrient Enrichment in the Nation's Estuaries", indicates that by the year 2020, conditions may worsen in the majority of estuaries, if population growth and development in the coastal zone is not managed properly.

According to NOAA scientist Dr. Suzanne Bricker, lead author of the report, the results developed from information and data collected over a seven year period from hundreds of experts, represent the best and most comprehensive understanding of the scale, scope and characteristics of nutrient associated problems affecting the nation's coastal water bodies to date.

To complete the study, NOAA compiled information about water quality parameters associated with nutrient enrichment and eutrophication for 138 estuaries and the Mississippi River Plume. Problem conditions range from excessive algal blooms to low dissolved oxygen, losses of submerged aquatic vegetation, and occurrences of nuisance and toxic algal blooms.

The results show that 44 of the 139 systems studied have significant problem conditions, and 40 have moderate problems. According to the report, these problem conditions are not isolated. Although they occur in estuaries along all coasts, the Gulf of Mexico and mid Atlantic regions have the greatest percentage of estuaries with high-level problems. These conditions have been shown by other studies to alter the uses of the estuaries, at times closing shell fishing beds, causing human health risks destroying habitat for fisheries, and leading to loss of tourism.

The NOAA study indicates that for the majority of estuaries with significant problems, human related nutrient inputs are an important influence on development of those problems. However, many of these estuaries are also naturally sensitive to nutrient inputs. "These results can be used to more effectively focus management of this problem and, specifically, to develop a national response strategy," says Bricker. For example, the priority for estuaries in serious condition should be reduction of nutrients. For those in less serious condition but in areas where coastal population growth puts them at high risk, the priority should be on monitoring and prevention of future degradation.

Nutrient related water quality problems have become worse in 48 estuaries since 1970 while in 14 estuaries conditions have improved. Alarmingly, scientists predict that conditions will become even worse in 86 estuaries by the year 2020 as population growth and development in the coastal zone increases. Conditions are predicted to improve in only eight estuaries. According to NOAA scientists, these results highlight the need for a strong national response to this pervasive problem.

For more information on the conditions of estuaries visit,