Gulf of Mexico Hypoxia Study
Investigations of the Gulf of Mexico’s inner shelf in the coastal waters of Louisiana and Texas have documented the seasonally observed oxygen depletion in this zone during the past several decades. Hypoxia, defined as dissolved oxygen concentrations of less than 2 mg/L, has apparently increased in intensity, size, and duration during the past half-century. The extent of the hypoxic zone has been observed to be as great as 20,000 sq. km, and appears to be the largest known hypoxic zone in the waters of the conterminous U.S. Land-use activity in the heartland of the U.S. appears to be influential in the hypoxic zone and the Mississippi-Atchafalaya River Basin appears to be the dominant source of macro- and micro-nutrients.
A multimedia high-resolution mathematical modeling framework based on the LM3-Eutro model is being developed that will consist of coupled eutrophication, dissolved oxygen (DO), and sediment diagenesis models. This modeling framework is based on sound mass-balance principles and integrate multimedia inputs (from statically-based monitoring programs) and ecosystem dynamics to establish a forecasting capability for exploring remedial options. The eutrophication/DO model is driven by a hydrodynamics model (EPACOM) and will receive loading from the Mississippi and Atchafalaya Rivers and an atmospheric model (Community Multiscale Air Quality (CMAQ)) model. The model will be calibrated and confirmed using cruise data collected from 2003 to 2007 along with other carefully evaluated project and non-project data. Uncertainty, sensitivity, and other statistical analyses will be performed to estimate the accuracy of the model predictions. Finally, the model will be applied to estimate several nutrient reduction scenarios, including the allowable nitrogen load that would limit the hypoxic area to a maximum of 5,000 km2 as was specified by the Gulf of Mexico Action Plan.
Pauer, J.J., A.M. Anstead, W. Melendez, R. Rossmann , K.W. Taunt, and R.G. Kreis, Jr. 2008. The Lake Michigan Eutrophication Model, LM3-Eutro: Model Development and Calibration. Water Environ Res., 80(9): 853-861.
James J. Pauer, Timothy J. Feist1 Amy M. Anstead, Wilson Melendez, Russell G. Kreis, Jr., and Kenneth R. Rygwelski. November 2008 Draft. Gulf of Mexico Modeling Research Plan and Quality Assurance Project Plan. U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division-Duluth, Large Lakes Research Station, Grosse Ile, Michigan.
Melendez, W., M. Settles, J. J. Pauer, and K. R. Rygwelski. 2009. LM3: A High-Resolution Lake Michigan Mass Balance Water Quality Model. U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Large Lakes Research Station, Grosse Ile, Michigan. EPA/600/R-09/020, 329 pp.
Rygwelski, K.R. 2005. Draft, Operating Procedure for U.S. EPA-Grosse Ile Model Archiving and Operating Guidelines. U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division-Duluth, Large Lakes Research Station, Grosse Ile, Michigan. LLRS-MCM-OP-001, 6 pp.
Greene, R., R. Kreis, P. Eldridge, J. Hagy, M. Murrell, J. Lehrter, and G. Thursby. 2006. Tools Supporting Coastal Nutrient Criteria Development. Board of Scientific Counselors (BOSC) Review, Cincinnati, Ohio, January 25, 2006. (Poster and Abstract)
Greene, R.M., J. Hagy, M. Murrel, J. Kurtz, J. Lehrter, and R.G. Kreis, Jr. 2005. Multimedia Mass Balance Modeling and Seasonal Monitoring of Hypoxia in the Northern Gulf of Mexico. Mississippi River Basin Nutrients Science Workshop. Presenters: R.G. Kreis, Jr. and J. Kurtz. St. Louis, MO, October 4-6, 2005, p. 34 (Abstract)
Greene, R.M., M. Murrel, J. Hagy, and R. Kreis, Jr. June 2004. Gulf of Mexico Hypoxia Monitoring and Modeling. Presented at the EPA Science Forum, Washington, D.C. June 1-3, 2004.
Kreis, R.G., Jr. and R.M. Greene. 2004. Gulf of Mexico Hypoxia Monitoring and Modeling. USEPA Gulf of Mexico Program Review. New Orleans, LA, October 27-28, 2004.
Greene, R.M. and R.G. Kreis, Jr. May 2003. Gulf of Mexico Hypoxia Modeling Framework: Improving the Science to Support Decision-Making. Presented at the EPA Science Forum, Washington, D.C. May 5-7, 2003.
Kreis, R.G., Jr., and R.M. Greene. 2002. Modeling and Field Sampling in the Gulf of Mexico. Briefing to the Gulf of Mexico Program Office and Regional Administrators of USEPA Regions 4, 5, 6, and 7. Gulf Breeze, Florida., December 5, 2002.