Comments on Draft Plan of Action for Reducing, Mitigating, and Controlling Hypoxia in the Northern Gulf of Mexico. 8-21-00 I make these comments as an individual and researcher involved in Gulf of Mexico hypoxia and linkages with the Mississippi River watershed, and not as a representative of my institution.
While this Action Plan is specific in its title to hypoxia in the Gulf of Mexico, it is obvious from the content that efforts to reduce hypoxia in the Gulf through control of nitrogen sources within the Mississippi River basin will accrue benefits to both the Gulf and water, habitats, and resources within the Mississippi watershed.
All of the long-term goals listed are laudable, but only goals 1A and 1B are measurable in the context of long-term changes and re-evaluation every five years. Thus, while restoring and protecting the natural resources and public health in the Gulf and the Mississippi/Atchafalaya River Basin (Goal 1C) are fine ultimate goals, they are too nebulous to be implemented.
Of Goals 1A and 1B, Goal 1B is an inclusive goal, because it combines a minimum extent of hypoxia in the Gulf with a nitrogen reduction goal. The goal of reducing the hypoxic extent in the Gulf to less than 5,000 square kilometers by the year 2010 is a measurable goal, specifically on a 5-year running, but needs to be accomplished by multiple measures that reduce nitrogen loading. To be more effective Goal 1B should be modified to read that "average nitrogen loads to the Gulf should be reduced by A MINIMUM of 30% from the 1980-96 average. Identification of specific actions within the basin, to achieve that MINIMUM 30% nitrogen load reduction." If greater than 30% reductions can be achieved, then we should strive to accomplish them. Other governmental entities, such as the Chesapeake Bay Agreement and the nations of the Baltic North Sea, have set higher and more realistic goals (40% and 50% nitrogen reduction, respectively) to meet coastal water quality improvements. The caretakers of the Mississippi River and the northern Gulf of Mexico should not want to stop short of these higher percentages. Also, Goal 1B should also be specific to a reduction of a minimum of 30% over a 5-year running average, similar to the change through time in the extent of the hypoxia size goal.
Goal 1A, while it encompasses the higher limit (40%) of other governmental entities around the U.S. and the world, stops short by allowing a reduction goal as low as 20% and is therefore unacceptable.
It is not clear in the reading of the document what "authority" will re-evaluate the progress to the goals on the 5-yr continuing basis.Section on "Implementation Actions," insert in the first sentence "for the benefits to the Gulf of Mexico [and within-basin watersheds]" It is not clear how short term action #6 integrates with the Gulf of Mexico Program procedures in place for an expert panel to identify research needs for Gulf hypoxia.
There is uneven emphasis on "coastal" states and the state of Louisiana. If part of the eventual plans for mitigating nutrient effects in the Gulf depend on redistribution of large quantities of Mississippi and Atchafalaya River waters, then the states of Texas, Mississippi, Alabama, and even Florida should be partners in actions specific to coastal issues. Even at present discharge distributions, the states of Texas and Mississippi should be working at the same level as Louisiana where indicated in the Action Plan.
The Clean Air Act, in its current status and with potential modification, needs to be addressed directly as it relates to atmospheric deposition and water quality within the Mississippi River basin. Management of nutrients needs to be an integrated watershed and airshed endeavor.
Under Key Roles and Responsibilities, the emphasis on nutrient criteria development within EPA, NOAA, States and Tribes should include not just nutrient criteria, but also the manifestations of nutrients, such as chlorophyll biomass levels.
Under Environmental Indicators, it will be difficult to measure the duration of the large hypoxic zone several times a year without a significant increase in funding for more than one shelfwide cruise annually. Duration for a smaller area can be determined from the monthly work off Terrebonne Bay and the transect off Atchafalaya Bay to be implemented in 2000. Also, it will be difficult to determine from actual data what the bottom-dwelling communities in the current hypoxic zone should return to, because there are no historic data. There are hypotheses, however, based on current understandings of benthic ecology that would be useful starting points.
The various actions outlined to accomplish the goals, specifically those identified in Goal 1A and 1B and in the supporting text, are well presented and should facilitate progress in nutrient reductions. There are many good, valid points raised in this document. I have mostly identified those above that need work or further clarification. The remainder of the document is on target. More emphasis may be afforded statements to the effect that several models of source loads within the basin indicate where emphases should be placed within the basin for action.
It is important that steps be taken to reduce nitrogen loads to the Gulf of Mexico and reduce the size of the hypoxic zone, not by small amounts, but by significant amounts. That water quality and resources within the Mississippi watershed will also benefit makes these actions even more supportable.Nancy N. Rabalais, Ph.D.