4-4 Aquatic Ecosystems Water covers ¾ of Earth, has an average depth of 3.7 (deepest part is 11 km – 6.8 mi) miles, contains about 3% salt and only 3% of surface water is fresh water, and is home to a variety of organisms

1. Aquatic ecosystems A. Determined primarily by the 1. depth 2. flow 3. temperature 4. chemistry of the overlying water B. Grouped according to the abiotic factors that affect them 1. ex. depth of water determines how much light is received 2. Freshwater ecosystems A. Divided into two main types

B. Flowing water ecosystems 1. Originate in the mountains/hills and flow downhill creating rivers, streams, creeks and brooks. 2. Organisms are adapted to slow or fast flowing water.

C. Standing water ecosystems 1. Relatively still waters provide habitats for many organisms that otherwise would be washed away. 2. Lakes and ponds have some flow of water to bring in fresh oxygen. 3. Microscopic organisms exists in this habitat. a. Plankton – free-floating organisms b. Phytoplankton – microscopic plants c. Zooplankton – microscopic animals

Plankton- free floating organisms

Phytoplankton- microscopic plants

Zooplankton- microscopic animals

3. Freshwater wetlands A. Wetland is an 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. 1. May be standing, flowing, fresh, salty, or brackish (containing some salt, brine) B. Very productive ecosystems rich in organisms. C. Three main types are 1. Bogs – dominated by moss 2. Marshes – dominated by cattails 3. Swamps – dominated by bushes and trees

Bogs- dominated by moss

Marshes – dominated by cat tails

Swamps – trees and bushes

A. Occurs where freshwater rivers and streams meet the sea. 4. Estuaries (aquatic nursery) A. Occurs where freshwater rivers and streams meet the sea. B. Contain fresh and salt water, and is a place where young aquatic organisms can develop and grow strong. 1. Bays, salt marshes, mangroves and mud flats

5. Marine Ecosystem A. Several classifications used to describe marine ecosystems. B. Photic zone is the this surface layer (down to 200 meters) in which sunlight penetrates. C. Aphotic zone which is permanently dark 1. Other zones are divided based on depth and distance from shore, intertidal, coastal and open ocean areas.

6. The Intertidal Zone – areas that are exposed to air during low tides. A. TIDE POOLS – found and make up the intertidal areas where animals must be adapted to the exposure of air part of every day. Must be able to withstand the force of the crashing waves. Zonation – bands of competition among organisms that live on different bands of rocky surfaces in the intertidal zone.

Tide Pools = Intertidal Zone

Zonation – prominent banding of organisms

8. Coastal Ocean A. Extends from the low-tide mark to the outer edge of the continental shelf. Being shallow enough to fall mostly within the photic zone. Very rich in plankton and many other organism that supports a complex food web. 1. Kelp forests 2. Giant brown alga 3. Seaweed

Kelp Forest

Brown Alga

Seaweed

9. Coral reefs A. Among the most diverse and productive environments on Earth. Located in the warm shallow waters of tropical coastal oceans. 1. Named for the coral animals whose hard, calcium carbonate skeletons make up their primary structure. 2. Coral and alga live symbiotically using each other to survive. 3. Usually within 40 meters of the surface.