Question

The map above shows the dissolved oxygen levels at various locations in the Gulf of Mexico. Aquatic wildlife usually is more heavily concentrated around coastlines and in estuaries where fresh and salt water meet. However, the map shows an anomaly to this phenomenon. What likely explains the dead zones around the coastline of the Gulf of Mexico?

Answer 1

Answer:

runoff containing nitrogen enters the Gulf from rivers, causing algal blooms and subsequent eutrophication.

Explanation:

Eutrophication is the reduction of dissolved oxygen due to an increase of algae, which subsequently die and decompose, consuming high levels of dissolved oxygen.