Chapter 20 Section 1 Review Page 500

1. Describe how water temperature affects the ability of the ocean water to dissolve gases. Warmer water is less able to dissolve gases than cooler water. (Think of a warm vs. cold soda)

2. Summarize how freezing and evaporation affect salinity. They can increase salinity. As water freezes or evaporates the salts are left in the water.

3. Describe the composition of ocean water. Ocean water is a mixture of water, dissolved solids (such as chlorine and sodium), and gases (such as oxygen, nitrogen, and carbon dioxide).

Salts in Ocean Water

4. Define thermocline. A layer in a body of water in which the temperature drops faster with increased depth than it does in other layers.

Thermocline

5. Describe how temperature and salinity affect the density of ocean water. Ocean water becomes denser as temperature decreases and salinity increases.

Density vs. Depth

6. Explain how the density of ocean water drives the movement of deep ocean currents. Cold, salty, dense water at the poles sinks and flows beneath warmer less dense water that is near the equator.

Deep Ocean Currents

Ocean currents surface/deep

7. Explain why shallow ocean water appears to be blue in color. When sunlight penetrates the ocean, the ocean water reflects the wavelengths of blue light and absorbs all other colors.

8. Why does the surface temperature of ocean water in middle latitudes vary during the year? The amount of incoming solar radiation varies greatly from season to season in these latitudes.

9. Why would surface water in the North Sea be more likely to contain a higher percentage of dissolved gases than the surface water in the Caribbean Sea? Surface waters in the North Sea are colder and colder water can hold more dissolved gases than warmer water.

10. If global temperatures increase, how would this change affect the ability of oceans to absorb CO2? Warmer water cannot hold as much dissolved gas as colder water so more CO2 would accumulate in the atmosphere.

11. If an area of the ocean has a large decrease in phytoplankton, how would this change affect other organisms? Explain your answer. Phytoplankton are at the bottom of the food chain so a decrease in the amount of phytoplankton would have a negative impact on all ocean life. There could be a decrease in the number of ocean organisms.

12. Use the following terms to create a concept map: ocean water, salinity, temperature, density, dissolved solids, and dissolved gases.

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