Which type of water quality issue is linked to improper nutrient management?

Improper nutrient management is directly linked to increased algal blooms and eutrophication, making it the correct answer. When excess nutrients, particularly nitrogen and phosphorus, are introduced into water bodies—often as runoff from agricultural fields—they can stimulate the rapid growth of algae. This phenomenon is known as algal bloom.

As these algae multiply, they can form thick mats that not only reduce light penetration but also deplete oxygen in the water as they decay, leading to hypoxic or anoxic conditions. This disrupts aquatic ecosystems, harms aquatic life, and can even lead to fish kills. Furthermore, some algal blooms produce toxins that can pose health risks to humans and wildlife, compounding the water quality issues associated with nutrient mismanagement.

In contrast, the other options do not effectively describe the link between nutrient management and water quality. Increased fishing populations are typically a result of balanced ecosystems rather than poor nutrient management. Reduced soil moisture does not directly relate to water quality but rather to soil health and nutrient levels. Decreased plant growth can be a consequence of too many nutrients in water impacting terrestrial growth, but it is not as directly tied to the immediate issues of water quality as algal blooms and eutrophication are.