What is the impact of increased nutrients in water systems?

Increased nutrients, particularly nitrogen and phosphorus, in water systems can lead to the phenomenon known as algal blooms. This occurs when excess nutrients, often from agricultural runoff, wastewater discharge, or other sources, enter a body of water. These nutrients serve as fertilizers for algae, causing rapid growth and proliferation.

Algal blooms can significantly alter the water quality and ecosystem dynamics. They may block sunlight from reaching underwater plants, disrupt the food chain, and produce toxins that can be harmful to aquatic life and human health. This process highlights the negative impact of nutrient pollution, as it can lead to hypoxic conditions (low oxygen levels) in the water, which are detrimental to fish and other aquatic organisms.

Thus, the correct choice illustrates the critical environmental issue of nutrient overloading and its specific consequence of promoting harmful algal blooms in aquatic environments.