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Donald F. Boesch
Gulf of Mexico Hypoxia Activities |
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Initiation of Research
While serving as Executive Director of the Louisiana Universities Marine Consortium during the 1980s I helped initiate the first systematic studies of the distribution, dynamics and causes of hypoxia (severe depletion of dissolved oxygen) in bottom waters of the inner continental shelf off Louisiana and Texas. Extensive subsequent research has evaluated the distribution and dynamics and the human role in exacerbating hypoxia has received much public attention, earning entry into Wikipedia as the Dead Zone. |
Integrated Assessment (12.6 MB)
Action Plan (6.4 MB)
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Integrated Assessment 2000
A congressionally mandated [section 604(a) and (b) of Public Law 105-383]
Integrated Assessment of the causes, consequences and potential solutions for Gulf hypoxia was conducted under the auspices of the Committee on Environment and Natural Resources of the President's National Science and Technical Council.
I served as on the Editorial Board for the peer review of the six Hypoxia Assessment Reports that were the foundation for the Integrated Assessment. In particular, I served as co-editor of the reports on characterization of hypoxia (Topic 1), ecological and economic consequences (Topic 3), and effects of reducing nutrient loads (Topic 4). Essentially, these assements demonstrated that intense and recurrent hypoxia is a relatively recent phenomenon related to the increased delivery of nutrients by the Mississippi-Atchafalaya river system, mainly from agricultural sources in the upper part of the catchment.
The Hypoxia Assessment Reports, the Integrated Assessment, and extensive public comments received can be accessed through the Hypoxia Assessment website. In addition to my responsibilities as an editor, I participated in a December 1999 workshop to address differences of opinion on the sources of nutrients and the role of river-borne organic carbon. I presented an analysis The Role of the Mississippi River in Gulf of Mexico Hypoxia: Oversimplifications and Confusion (pdf file) to demonstrate that land-based organic carbon can play but a minor role in causing shelf hypoxia.
The Integrated Assessment led to an Action Plan, endorsed in 2001 by the Federal Government and states and tribes within the basin, which has as a goal reducing the average areal extent of the Gulf of Mexico hypoxic zone to less than 5,000 square kilometers by 2015 by reducing the discharge of nitrogen to the Gulf through implementation of specific, practical, and cost-effective voluntary actions. |
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Contrarians
As is the case for climate change science, there are contrarians, often associated with the agricultural sector, who have critized the basis for conclusions linking agricultural nutrient sources and hypoxia. Their perspectives are provided by the American Farm Bureau Federation, Fertilizer Institute, Potash & Phosphate Institute, and the Illinois State Water Survey, as well as commentators associated with the Hudson Institute.
As is the case with climate science, however, there are very few agricultural scientists, hydrologists, or oceanographers who have taken serious exception with the findings of the Integrated Assessment. I published a rebuttal to one paper that raised questions about the linkage between nutrient enrichment and Gulf hypoxia. That paper entitled Continental shelf hypoxia: Some compelling answers was published in the journal Gulf of Mexico Science. wers |
Mississippi River delta
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EPA Region 4 Report
A draft EPA Region 4 report circulated during 2004 suggested that phosphorus rather than nitrogen needed to be controlled in order to reduce hypoxia. Together with two other senior scientists, I wrote a letter to Benjamin Grumbles, EPA Acting Assistant Administrator for Water, raising concerns about that report. The EPA conducted a peer review of that report and earlier drafts that had been widely circulated. I was one of the nine reviewers. The peer review raises substanial questions and issues related to the analyses and conclusions of the draft Region 4 report and EPA has discontinued efforts to further refine and publish the report. Rather, the need for control of both nitrogen and phosphorus will be considered in the ongoing Reassessment summarized below.
Reassessment 2005
The 2001 Action Plan called for an assessment by December 2005 and every five years thereafter of "the nutrient load reductions achieved and the response of the hypoxic zone, water quality throughout the Basin, and economic and social effects." Based on these assessments, the Task Force responsible for implementing the Action Plan would "determine appropriate actions to continue to implement this strategy or, if necessary, revise the strategy." The Task Force is undertaking a Reassessment that is not yet completed nearly two years after date called for and seven years after the original endorsement of the Action Plan. The Reassessment has included various symposia, workshops and evaluation by the EPA Science Advisory Board. The SAB convened a Hypoxia Advisory Panel (HAP) tasked to "conduct an evaluation of the complex scientific and technical issues that affect the causes, magnitude and duration of the hypoxic zone...as well as the priority and feasibility of management and control options in the Mississippi River Basin and Gulf to reduce it."
Thus, rather than assessing the nutrient load reductions achieved and their effects, in the absence of tangible progress the Reassessment is essentially revisiting the 2000 Integrated Assessment. Together with other colleagues who were involved in the Integrated Assessment I offered the Task Force comments on the direction of the Reassessment and support for the principal findings of the HAP draft report, which largely reaffirmed those of the Integrated Assessment. I also offered comments on the Draft 2008 Action Plan.
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