This document defines and describes various types of aquatic ecosystems. It discusses plankton, wetlands, estuaries, salt marshes, mangrove swamps, photic and aphotic zones in oceans, coastal oceans, kelp forests, coral reefs, and benthos. It also notes that aquatic ecosystems are determined by water depth, flow, temperature and chemistry, and that freshwater ecosystems can be flowing or standing water. Marine ecosystems are divided into intertidal, coastal, and open ocean zones based on depth and distance from shore.

1. 4-4 Aquatic Ecosystems

2. Plankton Tiny, free-floating organisms that occur in aquatic environments

3. phytoplankton Population of algae and other small, photosynthetic organisms found near the surface of the ocean and forming part of plankton.

4. zooplankton Tiny animals that form part of the plankton.

5. wetland Ecosystem in which water either covers the soil or is present at or near the surface of the soil for at least part of the year.

6. estuary Wetlands formed where rivers meet the ocean.

7. detritus Particles of organic material that provide food for organisms at the base of an estuary’s food web

8. Salt Marsh Temperature-zone estuary dominated by salt-tolerant grasses above the low-tide line and by seagrasses under water.

9. Mangrove swamp Coastal wetland dominated by mangroves, salt-tolerated woody plants.

10. Photic zone Well-lit upper layer of the oceans

11. Aphotic zone Permanently dark layer of the oceans below the photic zone

12. zonation Prominent horizontal banding of organisms that live in a particular habitat

13. Coastal ocean Marine zone that extends from the low-tide mark to the end of the continental shelf.

14. Kelp forest Coastal ocean community named for its dominant organism-kelp, a giant brown alga

15. Coral reef Diverse and productive environment named for the coral animals that make up its primary structure.

16. benthos Organisms that live attached to or near the ocean floor

17. Key concept Aquatic ecosystems are determined primarily by the depth, flow, temperature, and chemistry of the overlying water.

18. Key concept Freshwater ecosystems can be divided into two main types: flowing-water ecosystems and standing-water ecosystems.

19. Key Concept In addition to the division between the photic and aphotic zones, marine biologists divide the ocean into zones based on the depth and distance from the shore: the intertidal zone, the coastal ocean, and the open ocean.