Study: 'Legacy' phosphorus delays water quality improvements in Gulf of Mexico

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The same phosphorous that fertilizes the thriving agriculture of the Midwest is also responsible for a vast “dead zone” in the Gulf of Mexico near the Mississippi Delta.

The same phosphorous that fertilizes the thriving agriculture of the Midwest is also responsible for a vast “dead zone” in the Gulf of Mexico near the Mississippi Delta. Efforts to reduce the amount of phosphorus that enters the Mississippi River system are underway, but research led by the University of Illinois Urbana-Champaign suggests that remnants of the contaminant are left behind in riverbeds for years after introduction and pose an overlooked – and lingering – problem.

Phosphorus from wastewater and agricultural runoff flows downstream to the Gulf of Mexico, where it unintentionally fertilizes plankton. As the plankton eventually die and decompose, the process depletes the Gulf’s water of oxygen – a condition called hypoxia – and creates a dead zone for sea creatures like fish and shrimp. The federal Gulf of Mexico Hypoxia Task Force aims to achieve a 25% reduction in phosphorus flows to the Gulf by 2025. This target relies on individual states to achieve a 25% reduction and assumes that those reductions will quickly lead to the desired outcome.

Read more at: University of Illinois Urbana-Champaign

A new study examines how phosphorus from agricultural runoff can become buried and re-released in the Mississippi River system, possibly delaying water quality improvement efforts in the Gulf of Mexico. (Photo Credit: Lynn Betts)