We are integrating existing data sets collected in the Northern Gulf of Mexico to study hypoxia impacts on coastal ecosystems and associated fisheries. We are using probabilistic, data-centric modeling to assess the spatiotemporal dynamics of hypoxia and to understand and forecast fisheries and ecosystem impacts. Our research focuses on data-driven inferences driving hypoxia and fisheries dynamics, rigorous uncertainty quantification, and prudent forecasting methodologies for all coastal areas.
Why We Care
The northern portion of the Gulf of Mexico experiences an annual summer hypoxia event when over-enrichment of nutrients in the water causes very low levels of dissolved oxygen. The dead zone of low oxygen in the northern Gulf of Mexico, occurring from Texas to Louisiana, is one of the most intractable environmental issues facing the United States. Far-reaching corrective measures implemented since hypoxia developed in the early 1980s have not yet resulted in hypoxia mitigation. Year after year, the dead zone varies in size but persists, seriously degrading the ecological health of the region.
The current goal of our Northern Gulf of Mexico Ecosystems and Hypoxia Assessment (NGOMEX) program is to conduct research that will improve existing models or develop new quantitative models to determine population- to ecosystem-level effects of Gulf of Mexico hypoxia, both spatially and temporally, on ecologically and commercially important aquatic species. The overall objective is to quantify, through multidisciplinary ecosystem models or other methods, the ecological and socioeconomic impacts of hypoxia, including an evaluation of the effects of alternative management strategies on ecosystem function and living resource populations.
What We Are Doing
Over the past three decades, an enormous amount of data has been collected in the Northern Gulf of Mexico to study hypoxia and its impacts on coastal ecosystems and associated fisheries. Multiple governmental and academic institutions have collected these data during monitoring cruises conducted at various spatial scales, with frequencies ranging from bi-weekly
to annually. While the individual data products from these cruises are available through scientific publications and online data repositories, there has been limited progress in synthesizing these data within a common analysis framework.
We are systematically integrating these data sets using probabilistic, data-centric modeling to better evaluate the spatiotemporal dynamics of hypoxia and to understand and forecast how hypoxia affects fisheries and the ecosystem. Leveraging new hypoxia estimates, this study will focus on evaluating the effects of hypoxia on regional fisheries (penaeid shrimp, Gulf menhaden), as well as relationships to metrics currently being developed or used to monitor the state of and potential future changes to the Gulf ecosystem (i.e., “ecological indicators”) within the context of other ecosystem stressors. We will use these improved hypoxia and ecosystem prediction capabilities to develop enhanced fisheries forecasts that explicitly consider recent and future (forecasted) hypoxic conditions on the continental shelf. We will transfer our project results to the management community during facilitation and consultation sessions with the lead Application Principal Investigator, Dr. Kevin Craig from the NOAA National Marine Fisheries Service.
The project team consists of Dr. Daniel Obenour (Principal Investigator from North Carolina State University), and Dr. Kevin Craig (Application Principal Investigator with the National Marine Fisheries Service), whose role is to ensure the outputs and outcomes of the project are transferred effectively to the management community.
Benefits of Our Work
The research team will systematically integrate existing data sets using probabilistic modeling to thoroughly evaluate the spatiotemporal dynamics of hypoxia and to understand and predict the ecosystem impacts of hypoxia. In particular, the team will focus on the consequences of hypoxia for regional fisheries and for ecological indicators of upper-trophic-level fish community, which are currently being used or developed to monitor the state of the Gulf ecosystem. Results from the models and forecasts will have a strong empirical basis and quantified uncertainty, which are attractive to water quality and fisheries managers. Specific outcomes from this project will include:
1) Geostatistical estimates of hypoxic area and volume over the entire hypoxic season for the period of record (1985–present) based on the dissolved oxygen sampling data available from multiple cruise programs.
2) A probabilistic biophysical hypoxia model capable of simulating and forecasting dissolved oxygen on multiple sections of the continental shelf over the entire hypoxic season and entire period of record.
3) A new set of hypoxia metrics (area, volume, and duration, using multiple hypoxic thresholds: 1 mg/L, 2 mg/L, 3 mg/L) for multiple shelf sections, based on the results of the geostatistical and biophysical modeling.
4) Evaluation of hypoxia effects on catch and effort from the region’s two major commercial fisheries (Gulf menhaden, penaeid shrimp) that incorporates the new hypoxia estimates.
5) Evaluation of hypoxia effects within the context of other environmental and anthropogenic stressors on ecological indicators of upper-trophic-level fish community currently in use to monitor the status of the Gulf ecosystem.