Chapter 16: Oceans and Coastal Systems Quiz

Approximately what percentage of the world's population lives near the ocean?

• 33%

• 25%

• 40%

• 70%

Approximately what percentage of the United States' population lives in coastal areas?

• 17%

• 22%

• 53%

• 81%

Globally, over ________ million people live in low-elevation coastal areas that are less than 30 m (98 ft.) above sea level.

• 12

• 36

• 333

• 630

What is the difference between an ocean and a sea?

• The term sea is used to describe the global, interconnected water body covering 70% of the Earth's surface, whereas oceans refer to the individual basins within this global sea.

• An ocean is a vast body of water encompassing 70% of the Earth, whereas a sea refers specifically to a large, inland, saline body of water.

• Seas are generally smaller than an ocean and tend to be at least partly enclosed by land, such as large, inland, saline water bodies.

• Oceans tend to be composed primarily of salt water, while seas tend to be composed of a near even mixture of brackish and fresh water.

Which of the following statements best describes seawater?

• Seawater is pure water (H20).

• Seawater is a solution.

• The chemical composition of seawater has little spatial variability.

• The salinity of seawater is negligible.

The chemical composition of seawater may be affected by

• the atmosphere only.

• minerals only.

• marine organisms only.

• the atmosphere, marine organisms, minerals, and ocean sediments.

The worldwide average salinity of seawater is

• 0.05%.

• 3.5%.

• 5.5%.

• 7.5%.

Increasing ocean acidification has been attributed to

• changes in thermohaline circulation associated with the Pacific Decadal Oscillation.

• freshwater inputs from melting ice.

• coastal erosion caused by changes in stream flow and increased precipitation.

• ocean absorption of excess atmospheric carbon dioxide.

Within the mixing zone and thermocline, average temperature and salinity

• decrease with depth.

• increase with depth.

• remain fairly constant with depth.

• decrease within the mixing zone, but increases within the thermocline.

Which of the following is true of the Earth's coastlines?

• Most of the Earth's coastlines are relatively young and undergoing continuous change.

• The Earth's coastlines are among the oldest landforms on the planet.

• There are few inputs that directly affect the Earth's coastlines beyond tidal action.

• The Earth's coastlines show a remarkable degree of similarity across the planet.