Center for Sponsored Coastal Ocean Research (CSCOR)

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Gulf of Mexico Ecosystems & Hypoxia Assessment (NGOMEX)

Issue

The northern portion of the Gulf of Mexico ecosystem, which contains almost half of the nation's coastal wetlands and supports commercial and recreational fisheries which generate $2.8 billion annually, has undergone profound changes due to nutrient enrichment of Mississippi River water from land-based sources. This nutrient over-enrichment can lead to excessive production of algae. When this organic material sinks and becomes decomposed, dissolved oxygen in bottom waters is reduced, resulting in seasonal hypoxia (very low oxygen water) over the Louisiana continental shelf. Large areas of hypoxic bottom water, known as the "Dead Zone," are a re-current feature in the Gulf during the summer. Hypoxic waters can cause habitat loss, stress and even death to marine organisms; affecting commercial harvests and the health of impacted ecosystems.

Approach

To address the issue of hypoxia in the Gulf of Mexico, NCCOS' Center for Sponsored Coastal Ocean Research (CSCOR) is supporting multi-year, interdisciplinary research projects to develop a fundamental understanding of the northern Gulf of Mexico ecosystem with a focus on the causes and effects of the hypoxic zone and the prediction of its future extent and impacts. The research program is directed towards the goal of developing a predictive capability for the Louisiana continental shelf ecosystem within an adaptive management framework that connects monitoring, data analysis, model predictions and management actions with continuous feedback for improvement in each category. Current studies are documenting the dynamics of the hypoxic zone over the Louisiana continental shelf and helping to better define the biological, chemical, and physical processes that influence hypoxic zone development and determine its extent, and impacts on fisheries.

Accomplishments

CSCOR sponsored scientific investigations have documented the seasonal hypoxic zone off the Louisiana continental shelf since 1990. In the summer of 2002, the hypoxic zone reached its largest extent, measuring 22,000 km², an area greater than the size of Massachusetts. CSCOR studies have produced considerable evidence that increased nutrient loading from the Mississippi River system is the dominant factor in creating this hypoxia problem. Their hindcast and forecast models have been key tools to understanding the relationship between nutrient loading and hypoxic area, and have enhanced predicitve capabilities on which management strategies to reduce hypoxia are based. Studies have also documented the effects of Gulf hypoxia on the fine-scale distributions and health of fish and shrimp.

Management and Policy Implications

Knowledge gained through CSCOR’s northern Gulf of Mexico hypoxia research program directly influences future management decisions occurring in the Mississippi River basin. Data obtained through the program was used to calculate a five-year average size of the hypoxic zone in the Gulf, which is a key metric for setting and determining upstream nutrient management strategies. The studies comprising this program will lead to enhanced predictive models capable of examining a multitude of interacting factors influencing the size of the hypoxic zone (e.g., nutrient input, freshwater inflow, circulation patterns), and improve understanding of the hypoxia effects on commercially important species in the region. This will allow for the assessment of alternative management strategies that need to be adaptable to changing eutrophication and hypoxia conditions.

Current Projects

NEW PROJECT:

• Nitrogen, Microbial Food Webs, and Hypoxia

Projects Started in 2006:

• Reproductive and Population Effects of Moderate Hypoxia
• Improving the Accuracy of Hypoxia Models for the Northern Gulf of Mexico
• Integrated Observational Studies of Hypoxia in the Northern Gulf of Mexico
• Spatially-explicit, High-resolution Mapping and Modeling to Quantify Hypoxia Effects on the Living Resources of the Northern Gulf of Mexico
• Mechanisms Controlling Hypoxia of the LA Continental Shelf: Real Time Operations

Project Archive

Projects Started in 2003:

• Seasonal Mapping of Productivity and Nutrient Limitation
• Hypoxia, Fish, & Fisheries in the Northern Gulf of Mexico: An Ecosystem Approach
• Mechanisms Controlling Hypoxia on the Louisiana Shelf, project web site
• Hypoxia Studies in the Northern Gulf of Mexico, project web site

Projects Prior to 2003:

• Which Nutrients Really Determine C Flux and Hypoxia?
• An Integrated Monitoring and Modeling Assessment of the Oxygen Sources and Sinks in the Gulf's Hypoxic Zone.
• Hypoxia, Nekton and Habitat in the Northern Gulf of Mexico: Modeling and Retrospective Analyses
• Population-Level Effects of Large-Scale Hypoxia on Shrimp and Fish in the Northwestern Gulf of Mexico
• Development of Larval Fish Vertical Distribution Models for Use with Physical Transport Models, Biological Production Models, and Hypoxia Effect Models in the Northern Gulf of Mexico

Return to Hypoxia & Nutrient Pollution Web Site

Related Links

• CSCOR-supported Research Provides Foundation for Effective Management of the "Dead Zone" in the Northern Gulf of Mexico
• Gulf of Mexico Action Plan
• Commitee on Environment and Natural Resources (CENR) Gulf of Mexico Hypoxia Integrated Assessment
• Nutrient Enhanced Coastal Ocean Productivity (NECOP) Program (PDF)
• A Science Strategy To Support Management Decisions Related To Hypoxia In The Northern Gulf Of Mexico And Excess Nutrients In The Mississippi River Basin (PDF)
• EPA Mississippi River Basin & Gulf of Mexico Hypoxia Information Page
• EPA/Gulf of Mexico Program
• Hypoxia Watch System for the Gulf of Mexico
• Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA)
• NCCOS Gulf of Mexico Hypoxia Factsheet: Providing Key Information to Understand and Reduce the Impacts of Oxygen Depletion on Living Resources in the Gulf of Mexico(PDF)
• Coastal Hypoxia Research Program (CHRP)
• 2002 FRN for the Coastal Ecosystem Research Project in the Northern Gulf of Mexico

For More Information, Contact:

Libby Jewett
NOAA/NOS/NCCOS/Center for Sponsored Coastal Ocean Research
Phone: 301-713-3338 x 121
E-mail: Libby.Jewett@noaa.gov