Why did hypoxia occur in gulf of Mexico?

Hypoxia in the Gulf of Mexico is primarily caused by nutrient runoff from agricultural activities in the Mississippi River watershed, particularly nitrogen and phosphorus from fertilizers. This nutrient overload leads to algal blooms, which consume oxygen in the water as they decompose, resulting in low oxygen levels, or "dead zones." These hypoxic conditions can severely impact marine life, disrupting ecosystems and fisheries. Additionally, factors like water temperature and salinity can exacerbate the problem.