What does thermal pollution refer to?

Thermal pollution specifically refers to the increase in water temperature that occurs when industrial processes discharge heated water into nearby aquatic environments. This rise in temperature can significantly disrupt the delicate balance of aquatic ecosystems. Elevated water temperatures can lead to decreased oxygen solubility, which affects fish and other aquatic organisms, often resulting in reduced biodiversity and altered species composition in the affected waterways. Additionally, warmer water can enhance the growth of harmful algal blooms, further stressing aquatic life and degrading water quality.

The other options do not accurately define thermal pollution. Decreases in water temperature do not characterize thermal pollution; rather, they might involve cooling processes that could be beneficial in certain contexts. Pollution from heavy metals or organic materials instead pertains to chemical pollution types with different environmental impacts and mechanisms than those of temperature-related issues.