Which of the following is a consequence of high nutrient pollution in water?

High nutrient pollution in water, particularly from sources like agricultural runoff, wastewater discharge, and stormwater, leads to an excess of nutrients, primarily nitrogen and phosphorus. This overabundance of nutrients acts as a fertilizer for aquatic plants, particularly algae. As a result, harmful algal blooms can occur, where algae grow excessively and cover the surface of water bodies.

These blooms not only reduce light penetration, which can harm aquatic plants and disrupt ecosystems, but they can also produce toxins that pose health risks to humans and wildlife. Additionally, when these algal blooms die off and decompose, they consume large amounts of dissolved oxygen in the water, leading to hypoxia, which can cause fish kills and severely impact aquatic life.

While the other options may touch on aspects of water quality, they do not directly relate to the immediate and significant effects associated with high nutrient levels, which is the proliferation of harmful algal blooms. Thus, the choice highlighting the consequences of nutrient pollution specifically points to a well-documented and serious environmental issue.