From the article: What causes dead zones, and can they be reversed?

Edit Answers
12345678910111213
Across
  1. 3. these two states also have dead zones on their coastlines
  2. 4. a major cause of dead zones, also an essential component of bones
  3. 6. a primary cause of dead zones, also a component of protein
  4. 7. the Gulf of Mexico dead zone decimated this industry
  5. 9. lacking oxygen
  6. 13. what a water-based ecosystem does when two many nutrients are added to it
Down
  1. 1. location of the most infamous dead zone in the United States
  2. 2. a dead zone in this location cleared up after the cost of chemical fertilizer increased
  3. 5. a bay in the western part of the United states where a dead zone has been reversed
  4. 8. a river in eastern part of the United States where a dead zone has been reversed
  5. 10. a dead zone was first detected here in the 1970s
  6. 11. this hurricane worsened the hypoxic conditions in the Gulf of Mexico
  7. 12. spilling this will also worsen hypoxic conditions in water