Long-Term Trends of Water Quality and Biotic Metrics in Chesapeake Bay: 1986 to 2008

摘要: We analyzed trends in a 23-year period of water quality and biotic data for Chesapeake Bay. Indicators were used to detect improving worsening environmental health 15 regions 70 segments the bay assess estuarine ecosystem’s responses reduced nutrient loading from point (i.e., sewage treatment facilities) non-point (e.g., agricultural urban land use) sources. Despite extensive restoration efforts, ecological health-related (chlorophyll-a, dissolved oxygen, Secchi depth) (phytoplankton benthic indices) metrics evaluated herein have generally shown little improvement (submerged aquatic vegetation was an exception), clarity chlorophyll-a considerably worsened since 1986. Nutrient sediment inputs higher-than-average annual flows after 1992 combined with those highly developed Coastal Plain areas compromised ecosystem resiliency are important factors responsible depth mesohaline polyhaline zones 1986 2008.