Decrease in size of gulf’s ‘dead zone’ is encouraging

By Leslie Holloway, Jefferson City Director, State and Local Governmental Affairs, Missouri Farm Bureau
08/06/2009, St. Louis Today Commentary

The researchers quoted in the article "Smaller ‘dead zone’ belies water quality" (July 28) caution against reading too much into the significant decrease in the size of the Gulf of Mexico hypoxic zone compared to last year. The same can be said of an increase from one year to the next. In fact, the size of the hypoxic zone has fluctuated significantly since the Louisiana Universities Marine Consortium began its tracking in 1985.

The dynamics of hypoxia continue to puzzle scientists. Even the Louisiana Universities Marine Consortium researchers missed the mark when they predicted last summer’s "dead zone" would be the largest on record. It turned out to be about the same as the previous summer. The complexities of various nutrient compounds from natural and man-made sources in rural and urban areas moving through air, water and land are not yet understood. However, since the late 1990s, net nutrient inputs attributed to agriculture in the Mississippi River Basin have decreased, most notably in the upper basin. Although no direct correlation can be drawn between this statistic and the size of the hypoxic zone, this year’s decrease certainly is encouraging.