1. Relating to the natural world and the impact of human activity on it

2. A military installation for naval ships and submarines

3. A ring-shaped coral reef or island

4. An area of land under the jurisdiction of a particular country

5. Common Spanish surname meaning 'son of Garcia'

6. A biological community of interacting organisms and their physical environment

7. People who catch fish for a living

8. First name of the famous Mexican artist known for his murals

9. The process or fact of being alone or separated

10. A military airport used as a base for air operations

11. A place where military forces are stationed

12. Relating to a country's navy or warships

13. A hard stony substance secreted by certain marine polyps

14. A vast expanse of saltwater

15. A ridge of jagged rock, coral, or sand just above or below the surface of the sea

16. A large oval fruit with a hard shell and sweet white flesh