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In the summer of 1985, Nancy Rabalais set sail on a research vessel into the Gulf of Mexico—and into the scientific unknown.
At the time, scientists knew little about the vast expanses of low-oxygen water, called hypoxia, which sometimes appeared in the Gulf and other bays and rivers. That summer, Rabalais' team set out to discover how these areas connected with creatures that inhabit the bottom of the Gulf.
Analyzing water and sediment samples miles offshore, the team from the Louisiana Universities Marine Consortium and Louisiana State University quickly discovered that the hypoxia extended from the Mississippi River to Texas and lasted most of the summer.
Later, they pinpointed the cause: increased amounts of nitrogen and phosphorus in the Gulf, largely due to runoff from farm fertilizers and other sources in the Mississippi River basin.
Rabalais' research put the Gulf of Mexico on the scientific map and in the psyche of the nation, leading to the creation of the US Environmental Protection Agency. Mississippi River/Gulf of Mexico Hypoxia Task Force and a host of efforts to combat nutrient pollution, which the EPA calls “one of America's most widespread, costly and challenging environmental problems.”
For nearly four decades, Rabalais has become a giant in her field—testifying numerous times before Congress, mentoring countless students at LSU, and publishing some 160 studies.
Now 73, Rabalais said she no longer plans to go on the research cruises because of her age and health problems. But she remains dedicated to her work and educating the next generation.
“I believe in research that can support the common good,” he said. “This is one of those ways.”
The first days
Born in Wichita Falls, Texas, Rabalais grew up with a love for the water. He became certified in scuba diving at age 19, a skill that would come in handy when replacing monitors 60 feet below the surface of the Gulf.
She was fresh out of her PhD in zoology with a minor in marine science from the University of Texas at Austin when she took LUMCON's first hypoxia research cruise in the Gulf of Mexico in 1985, leading a full-time crew on the 116-footer. long research vessel Pelican.
“I just developed a tremendous amount of respect for her, not only for her commitment and her intelligence, but her drive,” said Don Boesch, LUMCON's first executive director.
The crew started from Terrebonne Bay and traveled about six to eight hours to reach the dead zone, where they took oxygen readings at designated stations. This network eventually grew from about 40 to 80 stations, spanning the coast from Louisiana to Texas.
Rabalais and her colleagues also dug into nutrient history, literally. By inserting tubes into the mud from the Gulf floor and slicing it, they were able to date the different layers of sediment and identify amounts of carbon and nitrogen from decades earlier. This proved that the Gulf was not always low in oxygen.
“We did all kinds of things to piece together the history and develop the long-term data set,” Rabalais said.
A lifetime of hypoxia research
Over time, the crew grew to include professors, scientists, students, and volunteers from various disciplines. One was fellow oceanographer Eugene Turner, now a professor at LSU. A linchpin in hypoxia research from the start, he also became Rabalais' partner and they married in 1988. Together, they worked to detail the causes and consequences of hypoxia in the Gulf.
By 1998, Rabalais was testifying before congressional committees to tell lawmakers why they should be concerned about hypoxia. As a result, Congress decided that federal funds should be given annually to the National Oceanic and Atmospheric Administration for hypoxia mitigation.
“When we started, she was laughing at me. He would say, “Oh, you're going to write a paper and change the policy?” Turner said. “But that's what we do.”
Rabalais was done executive director of LUMCON in 2005 and held the position until 2016. Her research has documented most of what we now know about Gulf hypoxia.
Dead zone of the Gulf caused by the outflow of Midwestern waters
From about May to September each year, the Gulf develops the largest hypoxic zone in the U.S. Hypoxic conditions occur when an area of water has less than 2 milligrams of oxygen per liter of water. It usually means the death or flight of most living organisms in the area.
Hypoxia can occur naturally in water, but humans have exacerbated the problem since the 20th century. Nutrient runoff from farm fertilizers and other sources washes into rivers and streams, increasing nitrogen and phosphorus in waterways.
Nutrients from states and counties in the Mississippi River basin wash into the watershed and into the Gulf in the spring and early summer. Fresh water with excess nutrients sits above the Gulf's salt water and causes algal blooms. The algae eventually die and sink into the salt water below, depleting the oxygen supply.
Matt Rota, senior policy director for the advocacy group Healthy Gulf, said addressing nutrient pollution is important to everyone.
“The things we do to cause the dead zone also cause us to have less healthy soil and cause the contamination of our drinking and recreational waters,” he said.
The hypoxic monster spread out approx 3,275 square miles of the Gulf in 2022. It was less than the previous year, mainly due to lower discharge from the Mississippi River. The region has become mostly larger over time, with a five-year average size still more than twice as large as Task Force Goal 2035. This year's annual forecast was expected on Tuesday.
“We're not on track,” Rabalais said of the goal. “I keep saying there is no social will.”
Fertilizers and agribusiness
Since the 1950s, the amount of nitrogen in the Mississippi River basin has tripled, and the amount of phosphorus has also increased, in part from fertilizer applied in Midwestern states.
Congress exempted agriculture from the Clean Water Act of 1972, leaving responsibility for nutrient pollution control to individual states. This limits EPA's ability to limit nutrient runoff from nonpoint sources such as farms. The result is multiple federally and state-sponsored efforts to reduce nutrients through voluntary programs for farmers, such as crop rotations to naturally enrich the soil without fertilizer.
But these efforts have yet to meet the goals of dramatically reducing the size of the dead zone. Some researchers and advocates argue that the responsibility for reducing runoff should lie with the agricultural system rather than individual farmers who often have little incentive to adopt voluntary changes.
For Rabalais, persistence is the name of the game. She believes that the role of the individual should not be overlooked – she eats less meat and avoids ethanol to reduce her personal impact.
“I try to maintain my optimism that good efforts can have good results.” she wrote in a reflection on her work in 2021.
A new era
As Rabalais ends her time at the helm of Gulf hypoxia research, she has tapped marine biologist Cassandra Glaspie to take the reins.
Glaspie studies benthic organisms, the creatures that live in bottom waters. After finishing a postdoctoral program at Oregon studying hypoxia, Glaspie became a professor at LSU in the same department as Rambalai.
In addition to leading the annual research cruise and some related studies going forward, Glaspie decides what the future holds for parts of Rabalais' lab. She wants to expand and update tracking efforts and create an internship for students from underrepresented groups, including child farmers.
But paying for future initiatives can be a challenge. NOAA provides funding for the research cruise to measure oxygen in the water, which maintains the data set over time. But continuing long-term study of contributing factors, such as nutrient partitioning, requires additional funding, which Glaspie and Rabalais have worked to secure.
The work is never finished, but Rabalai is optimistic about the future.
“I would like to see a healthy gap,” he said. “We can never go back to where we were, but we can make progress.”
This story is part of it The price of abundance, a special project investigating composting by the University of Florida College of Journalism and Communications and the University of Missouri School of Journalism, supported by the nationwide Pulitzer Center Connected Coastlines Reporting Initiative and distributed by Mississippi River Basin Ag & Water Desk.
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