1 - Gulf of Mexico Eutrophication

Question 1

What is a dead zone?

Answer 1

A hypoxic zone (low oxygen, <2 ppm) where most marine life cannot survive

Question 2

Where is the Gulf of Mexico dead zone?

Answer 2

Located at the mouth of the Mississippi River, it extends westward to the Texas coast

Question 3

What causes the dead zone?

Answer 3

nutrient enrichment, especially nitrogen and phosphorus from:
* Fertilizer runoff (from Midwest farming states)
* Sewage
* Animal waste
* Soil erosion

Question 4

What is the process in the formation of hypoxia?

Answer 4

1. nutrients fuel algal blooms
2. algae die
3. bacteria decompose them
4. oxygen is consumed
5. hypoxia

Question 5

What causes seasonal fluctuations?

Answer 5

farming practices, flooding, and hurricanes

Question 6

What is the process that it results in?

Answer 6

Eutrophication: Algae overgrowth reduces biodiversity and benthic biomass.

Question 7

What does the dead zone threaten?

Answer 7

Threatens marine life, particularly:
* 72% of U.S. shrimp
* 66% of oysters
* 16% of commercial fish

Question 8

What solutions are there?

Answer 8

• Use less fertilizer and better timing of application.
• Manage animal waste to avoid water contamination.
• Improve sewage treatment and monitor septic systems.
• Enforce industrial discharge regulations.
• Restore wetlands to filter nutrients before they reach the Gulf.