So, why does this happen year after year?
We look to the Mississippi watershed, a drainage system that connects 31 states, even parts of Canada. Whatever flows into it eventually makes its way down to the Gulf, but it’s not pure, clean water.
Fertilizer from farms and lawns, urban runoff, and discharges from sewage treatment plants all flow into the Big Muddy. This ultimately leads to excess nutrients, such as nitrogen and phosphorous, flowing into the Gulf. Those extra nutrients help plants like algae grow out of control, consuming oxygen in the water. This is called hypoxia and creates a literal dead zone. Fish and shrimp leave the area, and anything that can’t swim away, like crabs, worms, and clams, die.
How can we continue to reduce the dead zone’s size in years to come? One thing we can all do is implement better fertilizer practices to limit excess nutrients from entering our waterways.
https://www.fox4now.com/news/state/is-the-gulfs-dead-zone-coming-back-to-life