Which of the following can cause an increase in the density of ocean water?

• A. Increasing the temperature of the water
• B. Adding freshwater to the ocean
• C. Decreasing the temperature of the water
• D. Decreasing the salinity of the water

Answer: (C)

Verified step by step guidance

1. Understand the concept of density: Density is defined as mass per unit volume. In the context of ocean water, density is influenced by temperature, salinity, and pressure.
2. Analyze the effect of temperature: As temperature decreases, water molecules move closer together, increasing the density of the water. Conversely, increasing the temperature causes water molecules to spread apart, decreasing density.
3. Examine the role of salinity: Salinity refers to the concentration of dissolved salts in water. Higher salinity increases the mass of the water without significantly increasing its volume, leading to higher density. Lower salinity decreases density.
4. Consider the impact of adding freshwater: Adding freshwater dilutes the salinity of ocean water, reducing its density. This is because freshwater has a lower density compared to saltwater.
5. Conclude the correct factor: Decreasing the temperature of the water increases its density, as colder water molecules are more tightly packed. This aligns with the correct answer provided in the problem.