LSU AgCenter Research Combats Hypoxic Dead Zone

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Rexanna Powers

In Louisiana, the many twists and turns of the state’s coast add up to more than 7,700 miles of shoreline, which meet the waters of the 600,000 square-mile Gulf of Mexico. Formed more than 300 million years ago, the Gulf of Mexico is home to 15,420 species of sea-dwelling creatures. From the deep-sea floor to coastal estuaries, the Gulf has an astonishing biodiversity. However, since 1972 a 4,480 square-mile area has been identified as a biohazard.

Louisiana is a massive chunk of land that contains nearly 5,000 miles of navigable waterways, and most of them run directly into the Gulf of Mexico. The Gulf of Mexico receives roughly 50% of all watershed flow in the United States. This means that runoff into rivers, such as the mighty Mississippi, the Atchafalaya, the Vermilion and the Red River, ends up in Gulf waters. During rainfall events, water flows across surfaces and collects litter, petroleum, chemicals, fertilizers and other toxic substances. Pesticides and nutrients used in the watersheds of the U.S. states bordering the Gulf exceed those used in any of the other coastal zones in the United States. Recent years have seen the agricultural industries in states bordering the Gulf targeted and blamed for what is called the hypoxic dead zone.

Hypoxia simply means that waters have low oxygen, meaning that sea life has a difficult time thriving and surviving. Hypoxia is primarily a problem for estuaries and coastal waters and can be caused by a variety of factors, including excess nutrients, primarily nitrogen and phosphorus. These excess nutrients can promote algal overgrowth and lead to excessive richness of nutrients. As dead algae decompose, oxygen is consumed in the process, resulting in low levels of oxygen in the water. The direct effects of seasonally formed hypoxic dead zones include fish kills, which deplete valuable fisheries and drastically disrupt ecosystems. Fish can typically survive a hypoxic event by moving to waters with more oxygen but less mobile or immobile animals, such as mussels or crabs, cannot move to waters with more oxygen and are often killed during hypoxic events. Ultimately, hypoxia causes a severe decrease in the amount of life in hypoxic zones, which could be detrimental to the environmental sustainability of Louisiana waterways.

Hypoxia is a national problem that affects many areas of the agricultural industry — most notably the row cropping sector. Row crop practices have been criticized for many years for perceived lack of sustainability and efficiency but more recently have been charged with responsibility for hypoxia. As part of a $1.4 million grant from the Patrick F. Taylor Foundation, best management practices are being studied to help improve soil health, water quality and resource management and increase crop yields and income.

With environmental sustainability and the hypoxic dead zone in mind, the goal of this ongoing research is to promote agricultural system sustainability to reduce agricultural inputs contributing to the dead zone located in the Gulf of Mexico. In an effort to improve rates of adoption, the best management practices are researched on two model farms. In Napoleonville, Keith Dugas Farms Inc. serves as the model farm for sugarcane research. Cotton and grain research for this project is housed in Newellton at Hardwick Planting Co.

As government agencies become more involved in regulating U.S. watersheds, the need for innovative and efficient row crop production practices is ever present. LSU AgCenter researchers on this project, Lisa Fultz and Brenda Tubaña, are working diligently to provide Louisiana farmers a set of voluntary best management practices that are not only cost effective to implement but also environmentally efficient.

Efforts to reduce impacts on the environment have been encouraged throughout the agriculture industry for many years. The discovery of hypoxia in the Gulf of Mexico is arguably one of the most pressing environmental issues that the agricultural industry currently faces. With conservation and sustainability at the center of many agricultural conversations, the hypoxic dead zone in the Gulf of Mexico will not soon be forgotten. For LSU AgCenter researchers, this responsibility requires the agricultural industry in Louisiana to take efficient and effective steps to ensure that the industry is sustained for generations to come.

Rexanna Powers was the communications coordinator for a Patrick F. Taylor Foundation grant focused on nutrient management. She was a graduate assistant in the Department of Agricultural and Extension Evaluation and Education and completed her doctorate in May.

A crowd gathered on a farm watches a person speak.

LSU AgCenter researchers explain their research to producers at the Taylor Foundation model farms field day. AgCenter staff photo

3/14/2023 4:13:49 PM
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