Which of the following will occur as the temperature of water increases due to thermal pollution?

• A. The rate of photosynthesis in aquatic plants will always increase.
• B. The metabolic rates of aquatic organisms will decrease.
• C. The solubility of carbon dioxide in water will increase.
• D. The dissolved oxygen content in the water will decrease.

Answer: (D)

Verified step by step guidance

1. Understand the concept of thermal pollution: Thermal pollution occurs when water bodies experience an increase in temperature due to human activities, such as industrial discharge or power plant cooling systems. This temperature change can impact aquatic ecosystems.
2. Recall the relationship between temperature and dissolved oxygen: As water temperature increases, the solubility of gases like oxygen decreases. This is because warmer water holds less dissolved oxygen compared to cooler water.
3. Analyze the impact on aquatic organisms: Dissolved oxygen is essential for the survival of aquatic organisms. A decrease in dissolved oxygen can lead to stress or death for organisms that rely on oxygen for respiration.
4. Evaluate the incorrect options: The rate of photosynthesis in aquatic plants does not always increase with temperature; it depends on other factors like light intensity and nutrient availability. Metabolic rates of aquatic organisms typically increase, not decrease, with higher temperatures. The solubility of carbon dioxide in water decreases, not increases, as temperature rises.
5. Conclude that the correct answer is: The dissolved oxygen content in the water will decrease, as this aligns with the scientific relationship between temperature and gas solubility in water.