What causes the Louisiana Dead Zone?

The Louisiana Dead Zone is primarily caused by excess fertilizer runoff from agricultural activities, which leads to algal blooms in the Gulf of Mexico. When fertilizers rich in nitrogen and phosphorus are washed into waterways through rain and irrigation, they promote rapid growth of algae. This overgrowth creates a significant biomass that eventually dies and decomposes. The decomposition process consumes oxygen in the water, resulting in hypoxic conditions, or low oxygen levels, which can be detrimental to marine life. Fish and other aquatic organisms may die or be forced to leave the area, creating a "dead zone."

Understanding this process highlights the direct link between land-based agricultural practices and marine ecosystem health, emphasizing the need for better nutrient management to mitigate nutrient runoff and its impacts.