1. Coastal Wetlands
Land areas covered by salt water at least part of the year are called coastal wetlands
Provide habitat and nesting for fish and wildlife
Absorb excess rain to help prevent flooding
Filter out pollutants and sediments

2. Plants and Animals of Estuaries
Estuaries support many marine ecosystems
Rivers supply nutrients that have washed from the land
Sunlight and nutrients support large populations of plants and plankton
Larger marine animals feed from estuaries

3. Threats to Estuaries In populated areas, they were used as landfills
Pollutants include sewage, industrial waste, and agricultural runoff
Estuaries cannot cope with the excessive amounts of human pollution

4. Salt Marshes
In estuaries, where rivers deposit mineral rich mud, salt marshes form
Salt marshes support communities of clams, fish, and aquatic birds
Act as a nursery for shrimp, crabs, fish which are then consumed by other ocean animals or people

5. Mangrove Swamps
Mangroves are several species of small trees adapted for growing in shallow salt water
Mangroves have wide, above-ground root systems for support
Dense growth of mangroves in swampy areas are mangrove swamps
They help protect the coastline from erosion

6. Rocky and Sandy Shores
Rocky shores have more plant and animal diversity than sandy shores
Rocks anchor seaweed, sea anemone, mussels, and sponges
Sandy shores has abundant life in the water and sandy sediments
Barrier islands run parallel to sandy shores and protect the mainland from storms

7. Coral Reefs
Coral reefs are limestone ridges built by tiny coral animals called coral polyps that secrete skeletons of limestone that slowly accumulate into reefs
Thousands of species of marine plants and animals live in the cracks of reefs making them among the most diverse ecosystems on Earth
Are only found in shallow, warm salt water

8. Coral Reefs in Danger Coral reefs are fragile ecosystems
If the water gets too hot, too cold, too polluted for too long, the algae that live there will move or die--when this happens, the coral turns white and is known as coral bleaching
Bleaching is occurring more frequently now because of human activity

9. Oceans Sunlight penetrates only about 100 m (330 ft)
As a result, much of the ocean's life is concentrated here
Seaweed and algae grow anchored to rocks and phytoplankton drift on the surface

10. Plants and Animals of Oceans
Phytoplankton grows only where there is enough sunlight and nutrients
This makes the open ocean one of the least productive ecosystems
Phytoplankton use oils and air bubbles to keep from sinking to the bottom
The smallest herbivores (jelly fish shrimp, fish larvae) live near the phytoplankton they eat

11. Deeper in the Ocean The depths of the ocean are perpetually dark
Most of the food is dead organisms
Decomposers and filter feeders will be found here

12. Threats to the Ocean Oceans are steadily becoming more polluted
Runoff from fertilized fields may cause algal blooms
Waste from cities and industries, fertilizers, and sewage are the main sources of pollution
Overfishing is destroying some fish populations

13. Arctic and Antarctic Ecosystems
Ecosystems are marine
The Arctic Ocean is nutrient rich because of surrounding land masses
The Antarctic is the only continent never colonized by humans
Plankton is the basis for both of these food webs

14. Copy Now, Answer Later
Explain why estuaries are very productive ecosystems. Why are estuaries vulnerable to the effects of pollution?
Compare salt marshes with mangrove swamps.
Describe two factors that can damage coral reefs.
List two ways in which animals of the oceans are threatened.
Suppose the sea suddenly rose 100 m. What would happen to the world's coral reefs? Explain.