Texas A&M Oceanographer Receives $3.7 Million Grant to Study Gulf Dead Zone

The Northern Gulf of Mexico Ecosystems and Hypoxia Assessment Program of the National Oceanic and Atmospheric Administration (NOAA) recently announced first-year funding for a new study under DiMarco titled "Mechanisms Controlling Hypoxia: Integrated Causal Modeling," which is expected to continue for the next five years.

Dead zones, or hypoxia, occur when oxygen in water drops below 2 milligrams per liter. Severe hypoxia levels can result in fish kills and adversely affect many types of marine life.

DiMarco and his team have examined dead zones off the Louisiana and Texas coasts to track the size and frequency of these occurrences and, more importantly, identify key factors that contribute to them.

The official size of the dead zone found in 2008 off the coast of Louisiana, as measured by a group of investigators in Louisiana, was 7,988 square miles, the second largest since measurements began in 1985. This represents a land area greater than the state of Massachusetts.

The 2009 dead zone was predicted to be among the largest ever recorded, but actual observations showed it instead to be the fourth smallest on record. The predictions were based largely on the amount of nutrients entering the Gulf via the Mississippi River. The low levels of oxygen in dead zones are caused primarily by nutrient pollution from farm fertilizers and other sources as they empty into rivers and eventually into the Gulf of Mexico.

DiMarco and colleagues have found, however, that other factors such as wind and current reversals, low waves, summer heat and upwelling from coastal marshes and estuaries also contribute to hypoxia.

"This year's forecast, which did not do a very good job of predicting the actual size of the dead zone, underscores the importance of our research at Texas A&M," DiMarco said. "Unraveling the complex system of processes that create dead zones will lead us in the direction of better predictions. This has always been the overarching premise of our team's research. We also look forward to the continuation of our research efforts and working with other researchers around the Gulf on this important issue."

DiMarco is program manager and principal investigator for this new round of funding from NOAA, of which Texas A&M and Texas A&M University at Galveston will receive $501,398 this year and $2.82 million over five years, pending Congressional approval. Collaborating researchers at the Louisiana Universities Marine Consortium and Virginia Institute for Marine Sciences will receive the remaining funds.

Five other oceanography faculty and one Galveston faculty member are co-principal investigators for the study. Other principal investigators are from Dalhousie University, Coastal Carolina University, Louisiana State University, Louisiana Universities Marine Consortium and Virginia Institute for Marine Sciences.

DiMarco's earlier hypoxia studies were funded by NOAA from 2003 through 2009. With this most recent funding, the researchers plan to continue pursuing their quest to develop models that can predict when and where hypoxic, or dead, zones may occur.

Together with Oceanography Professor Tom Bianchi, DiMarco discovered a Texas-created dead zone area off the Texas coast in August 2007, a result of unusually heavy rains that poured water into the Brazos River. This first proven dead zone area that originated from Texas rivers was created where the water emptied into the Gulf.

In completing 16 research cruises and collaboratively sharing data with other programs, the Texas A&M researchers have already collected tens of thousands of data points through their hypoxia studies. More than 50 Texas A&M graduate students have participated in the project, logging more than 1,000 student days at sea. The work has also led to collaborative studies of hypoxia in other regions of the world, specifically the Yangtze and Huanghe (Yellow) rivers in China.