Living in the dead zone

June 2012

 Living in the Dead Zone

Dr. Nancy Rabalais spends a lot of time on the water. It’s where she’s at peace with nature—and it’s also where her lifelong passion lives … or dies. 

Late U.S. Sen. John Heinz once used the phrase “shared ideals realized” to express his belief that citizens working to witness shared ideals for all is what makes a society thrive. 

These are the same words inscribed on the back of a medal now possessed by Dr. Nancy Rabalais, executive director of the Louisiana Universities Marine Consortium. These six syllables also perfectly describe the scientist’s ongoing research on a deadly phenomenon found in our precious Gulf of Mexico.

Since Nancy’s first biology class in eighth grade, she knew science was where she felt most at home. She took biology courses throughout high school, and later graduated with both bachelor’s and master’s degrees in biology from Texas A&I University-Kingsville in the 1970s. 

“I went to a small, regional college, but they had a lot of marine-oriented courses,” Nancy says. “I got interested in scuba diving, and the biology and marine environment sort of came together. That’s the way I headed after that.”

Upon completion of her master’s degree, Nancy took a job at a marine lab, where she spent her days identifying various offshore organisms and samples. She was also busy publishing several papers about both the South Texas continental shelf and oil and gas development. In 1983, she graduated with a doctorate in zoology from the University of Texas.

Nancy then applied her strong educational background to the field she had developed a passion for. She began working with Dr. Don Boesch, the first executive director at LUMCON. There, the young scientist wrote chapters for and edited a book addressing the long-term effects of offshore oil and gas development.

Shortly after starting at LUMCON, Nancy was also put in charge of a project designed to investigate reports of low oxygen in the Gulf, as well as the effect the nitrate level from the Mississippi River had on the water. Some 28 years later, the research continues.

“We keep adding different collaborators, doing different things, and we haven’t run out of research questions yet,” Nancy says. “We’re doing a very good job, I think, of educating the public and research managers about these issues.”

Her research investigates a phenomenon known as dead zones—low-oxygen, or hypoxic, areas in the world’s oceans in which a vast majority of marine life cannot survive. The Gulf claims one of the world’s largest dead zones. The affected area, which can span the nearly 7,000-mile length of the Gulf Coast region depending on the environmental elements of a particular year, was first discovered in the 1970s.

The Mississippi River delivers a lot of freshwater, and that freshwater weighs less than the salty Gulf water, thereby creating a layered system. 

“That’s predominant from the spring through the early fall until it starts getting mixed with hurricanes or winter storms,” Nancy says.

When it’s not layered, oxygen that is in the atmosphere can diffuse across the water and down to the bottom. When the layered system occurs, the oxygen cannot make it all the way to the bottom. 

The Mighty Mississippi also brings in a lot of nitrate and phosphorus, which act as fertilizers for the single-celled organism phytoplankton. As a result of the infiltration from the river, these phytoplankton often die and sink to the bottom of the Gulf. 

“Because there’s so much phytoplankton load getting to the bottom, the bacteria are capable of stripping the oxygen out of the water,” Nancy says.

With no resupply of oxygen from the surface of the water reaching the ocean bottom, an oxygen deficiency occurs, thereby creating a dead zone.

This ecological process has led many to question whether the 2010 BP Deepwater Horizon oil spill had any effect on the dead zone. Nancy says some of the studies that are trying to determine whether it did or did not actually don’t have sufficient data to declare a verdict. 

But scientists are working to answer that question. LUMCON is set to begin a study funded by the BP Gulf of Mexico Research Initiative. The study will analyze both the concentration of oil in the water column and the concentration of oxygen. Though oxygen anomalies have been documented at about 1,000 meters near the wellhead, Nancy does not believe the oil had any effect on the Gulf dead zone.

For her extensive study of the dead zone over the years, Nancy was honored last year with the prestigious Heinz Award. The award was established by Teresa Heinz in honor of her late husband, Sen. Heinz, to celebrate the achievements of individuals in areas of greatest importance to him. Nancy was selected as 1 of 9 recipients to receive a $100,000 grant as part of the 17th annual Heinz Awards ceremony, which, in 2011, honored the contributions of individuals who value the importance of natural resources. Nancy says the money was put toward supporting the ongoing hypoxia research that is not funded in other ways.

“It’s a safety net for all of the things we want to do,” she says.

When Nancy isn’t conducting research cruises in the dead zone, she enjoys traveling, eating good food, listening to music, scuba diving, and spending time with her husband and daughter. 

Having learned to scuba dive as a college student, Nancy now gets to be in the water not only as a hobby, but also as a significant part of her work. With over 1.7 billion pounds of fish coming from the Gulf of Mexico alone each year, it’s evident that her work is vital to the sustainability of the Gulf Coast’s natural resources. PoV


The Gulf claims one of the world’s largest dead zones. The affected area, which can span the nearly 7,000-mile length of the Gulf Coast region depending on the environmental elements of a particular year, was first discovered in the 1970s.