External Peer Review of the Draft Region 4 Report, "Evaluation of the Role of Nitrogen and Phosphorus in Causing or Contributing to Hypoxia in the Northern Gulf, August, 2004"

General Statement on Fate of Draft Region 4 Report

The External Peer Review of the Draft Region 4 report, "Evaluation of the Role of Nitrogen and Phosphorus in Causing or Contributing to Hypoxia in the Northern Gulf, August, 2004," provided considerable insight regarding the various processes involved in hypoxia formation in the northern Gulf of Mexico. The peer review raised substantial questions and issues regarding the role and significance of these processes in producing hypoxia. EPA believes the discussion of these processes has produced a valuable dialogue regarding the issues needing consideration in future reassessment.

EPA believes that resolution of the questions and issues raised is complex and that additional evaluation and consideration will be required. EPA has therefore decided that resolution and further clarification of these issues is beyond the scope of the Region 4 report and is best addressed through the currently ongoing process of reassessment of the Gulf of Mexico Hypoxia Action Plan (hereafter referred to as Action Plan). EPA believes that further refinement, completion, and formal publication of the Draft Region 4 report would not contribute significantly to the resolution of identified issues or to the reassessment of the Action Plan. The reassessment process provides a greater opportunity for continuing dialogue on the issues identified through the paper and the peer review, and is a better vehicle to weigh the merits and limitations of theories and actions appropriate to address hypoxia in the northern Gulf of Mexico.

Background

EPA scientists in Region 4 (Atlanta) conducted a review of data and information regarding hypoxia in the northern Gulf of Mexico. This Region 4 staff assessment concluded that phosphorus, rather than nitrogen, may be the limiting nutrient controlling Gulf hypoxia. An unauthorized draft of the report was released in January of 2004. This report, because of its controversial conclusion regarding the role of phosphorus in Gulf hypoxia, caused a significant amount of concern among stakeholders. After considerable internal review by Region 4 EPA scientists, the Region released a significantly revised version of the draft report for a broader internal EPA review in April 2004. The report was revised based on the broader EPA review and released to the Hypoxia Task Force in August 2004, as an informational document with the specific purpose of encouraging discussion and posing questions for the reassessment of the Action Plan. The draft report, "Evaluation of the Role of Nitrogen and Phosphorus in Causing or Contributing to Hypoxia in the Northern Gulf, August, 2004," had not at that time been subjected to external peer review.

The August report, and the earlier drafts that were not prepared for release but were widely circulated outside EPA, raised concerns among Task Force members and stakeholders throughout the Mississippi Basin. In response, the Task Force requested an expedited scientific peer review of the August 2004 draft report to be coordinated by the Monitoring, Modeling and Research Workgroup (MMR). Concerns were raised at the September 1, 2004 public meeting of the Task Force that earlier versions of the report (January and April drafts) should also be included in the review. Thus, the Task Force decided to include the two draft versions of the report, along with the August 2004 Report, in the peer review request.

The Coordinating Committee of the Task Force, in coordination with the MMR, examined several options for the external peer review. These groups concluded and the Task Force agreed that adapting the process employed by EPA to seek expert reviews of internal scientific and policy papers would allow for appropriate input from the Task Force while maintaining an independent and impartial review. EPA's Office of Science and Technology (OST), Health and Ecological Criteria Division (HECD) retains a contractor for the specific purpose of peer review. These peer reviews are performed following the guidelines contained in the EPA Science Policy Council Handbook: Peer Review (2000). This external peer review and the public scientific input process conducted during the external peer review have now been completed.

The Agency supports the consensus of the peer review that a dual nutrient reduction strategy is likely to be most effective for limiting algal bloom development and consequently hypoxia formation in the Gulf of Mexico. The comments of the peer reviewers advocate reduction of both nitrogen and phosphorus to reduce the size of the hypoxic zone and we believe these comments have significant merit and should be further examined in the course of the reassessment as called for in the Action Plan.

EPA has summarized the responses to each charge question. All issues raised by the external peer reviewers will be submitted to the Interagency Task Force on Gulf of Mexico Hypoxia to be considered for inclusion in the Reassessment of the Action Plan process.

Peer review summary and EPA responses
Full comments (PDF, 287K, 69 pp.)

EPA appreciates the efforts of the members of the public that provided public scientific views of the Region 4 reports, and has carefully considered all comments provided. We summarize the main points of the public views below. This summary will be provided to the Task Force to be considered as the Task Force moves forward to conduct the reassessment of the goals of the Action Plan.

Public input summary and EPA responses