Wetlands, Estuaries and Oceans

1. Wetlands, Estuaries and Oceans Unit 4

2. Wetlands and Estuaries • What is a wetland? • lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface • What is an estuary? • A partially enclosed body of water formed when freshwater (streams, groundwater, etc.) empties into the ocean

3. Wetlands and Estuaries • Why are they important? • Wetlands perform valuable functions including: • water quality and flood protection • act as filters, removing pollution from runoff • plants and soils also act as a natural buffer between the land and the ocean • prevent erosion and stabilize the shoreline. • Estuaries are critical to the survival of tens of thousands of birds, mammals, fish, and other wildlife. • serve as nursery grounds for two-thirds of the nation's commercial fish and shellfish

4. Wetlands and Estuaries • What is happening to them? • agriculture pesticide runoff • commercial and residential development • road construction • resource extraction

5. Wetlands and Estuaries • Why is it important to us? “ecosystem services” • Bees and other insects pollinate many of the crops we eat. • Birds and bats eat insect pests that threaten the crops. • Forests supply wood for our houses. • Many people eat wild plants, fish and game. • Our drinking water is purified by forests and wetlands. • Bacteria break down our wastes. • Plants, bacteria and fungi help to cure disease and maintain health.

6. Origin of the Oceans • Earth’s first oceans likely formed more than 4 billion years ago. Where did the water come from? • Some water may have come from impacting comets or from deep within Earth’s interior. • Scientists theorize that water from within Earth’s interior was released by volcanism.

7. Distribution of Earth’s Water The Blue Planet • Approximately 71 percent of Earth’s surface is covered by oceans. • The oceans contain 97 percent of the water found on Earth. Major Oceans • The major oceans are the Pacific, Atlantic, Indian, Arctic, and Antarctic.

8. Distribution of Earth’s Water Major Oceans

9. Seawater • Seawater is a solution of water and dissolved salts. • The most abundant salt in seawater is sodium chloride (NaCl). Table salt

10. Salinity • Salinity is a measure of the amount of dissolved salts in seawater

11. The actual salinities of the oceans vary from place to place. Variations in Salinity • Salinities may be high in subtropical regions where rates of evaporation exceed those of precipitation. • Salinities are lower in equatorial regions where precipitation is abundant. • Salinities in polar regions are diluted by melting sea ice.

12. Chemical Properties of Seawater

13. Density • Density measure of the compactness of a substance. • Seawater is denser than freshwater because salt ions are heavier than water molecules. • The density of seawater differs depending on the salinity and temperature. • Salt ions interfere with the formation of hydrogen bonds, the freezing point of seawater is –2°C.(28°F).

14. Ocean Layering • Ocean surface temperatures range from the polar waters to the equatorial regions • Average surface temperature being 15°C (59°F) • Ocean water temperatures decrease significantly with depth.

15. Ocean Layering • A typical ocean temperature profile

16. Ocean Layering • Based on temperature variations and density, the ocean can be divided into three layers. • The surface layer is a relatively warm, sunlit, surface layer some 100 m thick. • The thermocline is a transitional layer which is characterized by rapidly decreasing temperatures with depth. • The bottom layer is cold and dark with temperatures near freezing. • Both the thermocline and the warm surface layer are absent in polar seas, where water temperatures are cold from top to bottom.

17. Ocean Layering- Draw in notes