Nitrogen Loading Into Mississippi River To Cause Expansion Of Marine Dead Zone To 10,000 Square Miles

By Vittorio Hernandez – AHN News Writer
June 26, 2008 8:56 a.m. EST
Des Moines, IA (AHN) – The marine dead zone resulting from the Midwest flooding is expected to expand to over 10,000 square miles, according to researchers from the Louisiana State University and the Louisiana Universities Marine Consortium.
The water in the dead zone, approximately the size of Massachusetts, does not have sufficient oxygen at depth to support marine life. Since 1990, the zone, located off the coasts of Louisiana and Texas, usually covers 6,000 square miles, varying according to the flow of the Mississippi River.
Its low oxygen content is caused by the presence of large algae blooms which feeds on nitrogen and phosphorus from crop fertilizers, dead plants, lawn chemicals and sewerage than flow down the Mississippi. After the algae dies it consumes oxygen.
With the Mississippi flow up by 75 percent compared to last year’s level, nitrogen levels of water pouring into the gulf is expected to go up by 37 percent, the highest on record.
Eugene Turner of LSU blamed farmers who increased their crops to accommodate the high demand for biofuel for the high nitrogen loading into the Mississippi. But Rick Robinson, representing the Iowa Farm Bureau Federation, disputed Turner’s conclusion since corn acres went down in 2008 in Iowa. "That is a politically expedient statement to make, but it’s not based on scientific fact," Robinson said, quoted by the Des Moines Register.
Meanwhile, the Midwest flooding has caused a decline in the tourism revenues of Hannibal in Montana, the rural town where 19th century writer Mark Twain spent his childhood. Until the flood, the income of the Mark Twain Riverboat rose steadily by 3 to 5 percent every year.
The riverboat and a jambalaya restaurant had to temporarily close as tourists canceled reservations upon hearing of the rise in Mississippi River’s waters and inundation in nearby areas. Levees, however, saved Mark Twain’s town from the catastrophe that Cedar Rapids and other Midwestern towns suffered.