Aquatic Ecosystems

2. Zone The upper layer of a body of water through which sunlight can penetrate and photosynthesis occurs.
4. The land area that drains water into a particular stream, river, or lake.
7. Ecosystem An ecosystem found in saltwater environments such as oceans, coral reefs, and estuaries.
12. Microscopic organisms that drift or float in water; base of most aquatic food webs.
14. A partially enclosed coastal area where freshwater from rivers mixes with saltwater from the ocean.
15. Small, often microscopic animals that feed on phytoplankton.
16. Ecosystem An ecosystem located in a body of water, such as an ocean, lake, river, or wetland.
18. Organisms that live on or in the bottom of a body of water, like clams, crabs, or worms.
19. The concentration of salt in water.

1. Photosynthetic plankton (plant-like organisms) that produce oxygen and serve as primary producers.
3. A layer in a body of water where temperature changes rapidly with depth.
5. Ecosystem An ecosystem found in water with low salt content, like lakes, rivers, ponds, and streams.
6. Zone The area of vegetation along the banks of rivers or streams.
8. The process by which a body of water becomes overly enriched with nutrients, leading to algae growth.
9. An area where the land is saturated with water for part or all of the year, supporting aquatic plants.
10. The movement of cold, nutrient-rich water from deep in the ocean to the surface.
11. Zone The deeper layer of water where sunlight does not reach.
13. Reef A diverse marine ecosystem built by colonies of coral polyps.
17. Free-swimming aquatic animals, such as fish, whales, and squid.
18. Water Water that has more salinity than freshwater but less than seawater, often found in estuaries.