Gulf of Mexico Hypoxia Watch Bottom Dissolved Oxygen (mg/L) Contours for June and July 2004

The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen (milligrams per liter; mg/L) near the sea floor over the Texas-Louisiana continental shelf during a period that extends from mid-June to mid-July. The NOAA National Marine Fisheries Service Mississippi Laboratories at Pascagoula and Stennis Space Center and the NOAA National Coastal Data Development Center (NCDDC) at Stennis Space Center began the Hypoxia Watch project in 2001. Scientists aboard the NOAA Research Vessel Oregon II measure seawater properties, such as water temperature, salinity, chlorophyll, and dissolved oxygen at each of approximately 240 locations as the Oregon II cruises the waters south of Pascagoula, MS and then makes its way from Brownsville, Texas, to the mouth of the Mississippi River. A scientist aboard the ship processes the measurements from electronic dissolved oxygen sensors, checks the measurements periodically with chemical analyses of the seawater, then sends the data by e-mail to NCDDC at Stennis Space Center approximately every three to four days. Physical Scientists at NCDDC transform the dissolved oxygen measurements into contour maps, which identify areas of low oxygen, or hypoxia. During the thirty-day cruise, as the data is received from the ship, NCDDC generates new maps and immediately publishes them on the web. The first map will usually cover an area off the Mississippi coast, successive maps will add areas of the continental shelf from Brownsville to Corpus Christi, and the final map will usually cover the entire Texas-Louisiana-Mississippi coast. Maps are published every three to four days from approximately June 22 to July 20.