Oceanography: Ocean Salinity and Gases

Ocean water is salty due to dissolved salts, primarily sodium chloride. Salinity varies by location, being lower in the tropics and higher at the poles. Salts originate from land materials washed into the ocean. Over 90 elements, including oxygen, are found in seawater. Fish use gills to extract oxygen from water.

What is the primary salt found in ocean water?

• Potassium chloride

• Sodium chloride

• Calcium carbonate

• Magnesium sulfate

How does the salinity of ocean water vary in different regions?

• It is lower in the tropics and higher at the poles.

• It is uniform across all regions.

• It is higher in the tropics and lower at the poles.

• It is higher near the equator and lower near the poles.

Where do the salts in the ocean primarily come from?

• Rocks and soils on land

• Marine organisms

• Atmospheric deposition

• Volcanic eruptions

What happens to the salts when ocean water evaporates?

• They evaporate with the water.

• They are left behind in the ocean.

• They form new compounds.

• They dissolve in the atmosphere.

Which body part allows fish to extract oxygen from seawater?

• Scales

• Gills

• Fins

• Lungs