Dissolved Oxygen Maps for Summer 2005
During the summer of 2005, the Long Island Sound Water Quality Monitoring Program continued monitoring the extent of summertime hypoxia. The Program collected samples for nutrient analysis and water quality parameters from 17 stations, as well as phytoplankton and zooplankton samples from 6 stations located throughout the Sound. An additional 20 – 30 sites were sampled during the summer for dissolved oxygen (DO) to get a more accurate idea of the extent of hypoxia. Under the program, hypoxia is defined as low dissolved oxygen below the DO water quality standard.
For the summer of 2005, the estimated start of the hypoxic event was July 14th. Under the new DO standard of 3.5 mg/L of dissolved oxygen, the maximum area affected by hypoxia, seen during our August 2 – 4, 2005 survey, was 300 square miles. Under the old DO standard of 3.0 mg/L of dissolved oxygen, the maximum area affected by hypoxia was 177 square miles. For comparability to previous years, the duration, start date and end date were estimated using the 3.0 mg/L DO standard. The duration was 69 days with an estimated end date on or about September 20.
(Select map below to link to a larger image)
August 29 - September 2, 2005 
August 16 - 19, 2005
August 2 - 4, 2005 
July 18 -21, 2005 
July 7 - 12, 2005