Less oxygen dissolved in the water is often referred to as a “dead zone” because most marine life either dies or leave the area. (Photo: NOAA)
Very large dead zone expected for the Gulf of Mexico
Wednesday, June 19, 2013, 22:50 (GMT + 9)
Scientists are expecting a very large “dead zone” in the Gulf of Mexico and a smaller than average hypoxic level in the Chesapeake Bay this year, based on several National Oceanic and Atmospheric Administration (NOAA) -supported forecast models.
NOAA-supported modelers at the University of Michigan, Louisiana State University, and the Louisiana Universities Marine Consortium are forecasting that this year’s Gulf of Mexico hypoxic “dead” zone will be between 7,286-8,561 sqmi, which could place it among the ten largest recorded. That would range from an area the size of Connecticut, Rhode Island and the District of Columbia combined on the low end to the New Jersey on the upper end. The high estimate would exceed the largest ever reported 8,481 sqmi in 2002.
The Gulf estimate is based on the assumption of no significant tropical storms in the two weeks preceding or during the official measurement survey cruise scheduled from 25 July - 3 August 2013. If a storm does occur the size estimate could drop to a low of 5344 sqmi.
A second NOAA-funded forecast, for the Chesapeake Bay, calls for a smaller than average dead zone in the nation's largest estuary.
The forecasts call for a mid-summer hypoxic zone of 1.46 mi3, a mid-summer anoxic zone of 0.26 to 0.38 mi3, and a summer average hypoxia of 1.108 mi3, all at the low end of previously recorded zones. Last year the final mid-summer hypoxic zone was 1.45 mi3.
The dead zone in the Gulf of Mexico affects nationally important commercial and recreational fisheries, and threatens the region’s economy. The Chesapeake dead zones, which have been highly variable in recent years, threaten a multi-year effort to restore the Bay’s water quality and enhance its production of crabs, oysters, and other important fisheries.
“Long-term nutrient monitoring and modeling is key to tracking how nutrient conditions are changing in response to floods and droughts and nutrient management actions,” said Lori Caramanian, deputy assistant secretary of the interior for water and science. “Understanding the sources and transport of nutrients is key to developing effective nutrient management strategies needed to reduce the size of hypoxia zones in the Gulf, Bay and other US waters where hypoxia is an on-going problem.”
The confirmed size of the 2013 Gulf hypoxic zone will be released in August, following a monitoring survey led by the Louisiana Universities Marine Consortium beginning in late July, and the result will be used to improve future forecasts. The final measurement in the Chesapeake will come in October.