Chapter 6 Ecosystems Section 3 Aquatic Ecosystems A

Chapter 6: Ecosystems Section 3: Aquatic Ecosystems

A. Freshwater ecosystems – include flowing and standing water, low or no salt 1. Rivers and streams – flowing water

a. Most nutrients washed into the water from land b. The faster the flow, the greater the oxygen content

2. Lakes and ponds – very little flow a. Sunlight warms and lights pond bottom, supporting plant and animal life

b. Deeper lakes support life along shallow shoreline or surface

3. Water pollution – a problem caused by fertilizer-filled runoff and sewage

4. Wetlands – regions wet all or most of the year a. Lie between solid land water b. Very fertile ecosystems

B. Salt water ecosystems – 95% of Earth’s water contains high concentration of salt, or high salinity

1. Open oceans – divided into lighted and dark life zones a. lighted – upper 200 m and home of plankton

b. dark – below 200 m where animals feed on material that floats down or prey on each other

2. Coral reefs diverse and fragile ecosystems formed from coral shells of calcium carbonate

3. Seashores – along coastlines a. Intertidal zone covered with water at high tide and exposed to air at low tide

b. Drastic changes in temperature, moisture, salinity, and wave action

4. Estuaries where a river meets an ocean; called bays, lagoons, harbors, inlets, sounds Elkhorn Slough, CA

a. Rich in nutrients b. Changing mixture of salt water and freshwater Healthy estuary – Chesapeake Bay (largest estuary in the US)