‘Dead zone’ not a record, ties for No. 2

• By AMY WOLD
• Advocate staff writer
• Published: Jul 29, 2008 - Page: 10A - UPDATED: 12:05 a.m.

• Print
• Email
• Save
• Twitter
• Social Media

• Del.icio.us
• Digg
• Facebook
• Reddit
• 

This summer’s “dead zone” off the coast of Louisiana isn’t a record-breaker, but it does rival some of the largest low-oxygen areas measured in the Gulf of Mexico.

Nancy Rabalais, executive director of the Louisiana Universities Marine Consortium in Cocodrie, recently completed her yearly survey of the coastal dead zone and released the results Monday.

She and a team of scientists from LSU and University of Iowa found the dead zone measured 8,000 square miles from July 21 through July 27.

That means this year’s size ties with the one found in 2001 as the second-largest dead zone measured in the Gulf of Mexico since hypoxia mapping started in 1985, according to a press release from LUMCON.

The largest measured dead zone occurred in 2002 when it measured 8,400 square miles, LUMCON reported.

Earlier this year, Eugene Turner, professor at the School of Coast and Environment at LSU, came out with his prediction for the dead zone based on measured amounts of nutrients coming down the Mississippi River.

Those measurements were put into a formula used to provide a forecast size for the dead zone of 8,800 square miles.

The dead zone, also known as hypoxia, forms during summer months after nutrients from fertilizer, urban runoff and other sources flow down the Mississippi River into the Gulf of Mexico.

This nutrient-rich water helps feed the grown of microscopic organisms which use up oxygen when they die, fall to the water bottom and decompose.

In the summer, this low-oxygen water doesn’t get mixed with the oxygen-carrying water in the top layer.

This creates a “dead zone” where oxygen levels in the water are too low to support life.

Turner’s prediction took into account the larger than normal amounts of nutrients from agriculture sources and from higher than normal water flows down the Mississippi River this spring.

“The nitrogen loading to the Gulf of Mexico in May of this year was 37 percent higher than 2007 and the highest since measurements began in 1970,” according to the LUMCON news release.