Researchers at the University of Michigan have predicted that a dry spring in areas of the Midwest this year will result in the second-smallest Gulf of Mexico "dead zone" on record.

The forecast is for a 2012 Gulf of Mexico dead zone of about 1,200 square miles, an area the size of Rhode Island. If the forecast is correct, 2012 would replace 2000 (1,696 square miles) as the year with the second-smallest Gulf dead zone. The smallest oxygen-starved, or hypoxic, zone was recorded in 1988 (15 square miles).

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 The ‘dead zones’ are caused for the most part by farmland runoff containing fertilizers and livestock waste entering the Mississippi river; Nitrogen and phosphorus flowing down the Mississippi each year during late spring and summer cause explosive algal blooms in the Gulf of Mexico. When the algae die and sink, bottom-dwelling bacteria decompose the organic matter, consuming oxygen in the process and creating an oxygen-starved region or “dead zone” where other aquatic life cannot survive.

Aquatic ecologist Donald Scavia, professor at the U-M School of Natural Resources and Environment, said last week, "While it's encouraging to see that this year's Gulf forecast calls for a significant drop in the extent of the dead zone, we must keep in mind that the anticipated reduction is due mainly to decreased precipitation in the upper Midwest and a subsequent reduced water flow into the Gulf. The predicted 2012 dead-zone decline does not result from cutbacks in nitrogen use, which remains one of the key drivers of hypoxia in the Gulf."

He continued, "These dead zones are ecological time bombs. Without determined local, regional and national efforts to control nutrient loads, we are putting major fisheries at risk."

However, researchers from the National Oceanic and Atmospheric Administration announced on Thursday that the dead zone could remain within the average range of 6,000 square miles. The NOAA forecast factors in the hangover effects of the previous year’s pollution, which was extreme and can persist in bottom sediments.

The amount of nitrogen entering the Gulf of Mexico each spring has increased about 300 percent since the 1960s, mainly due to increased agricultural runoff. The Gulf of Mexico/Mississippi River Watershed Nutrient Task Force has targeted 1,900 square miles as a long-term goal for the size of the Gulf dead zone. The actual size of the dead zone will be announced by 3rd August.

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