Which characteristic is true about the nutrient enrichment caused by runoff?

Nutrient enrichment caused by runoff is primarily characterized by the increase of nutrients, particularly nitrogen and phosphorus, entering aquatic ecosystems. This excessive nutrient input can lead to the overgrowth of algae, termed harmful algal blooms (HABs). These blooms can produce toxins that are detrimental to aquatic life, wildlife, and even human health.

The presence of abundant nutrients creates an environment that favors excessive algal growth. When these blooms deteriorate, they can deplete oxygen levels in the water, leading to hypoxic or anoxic conditions that further threaten fish and other aquatic organisms. Consequently, the proliferation of harmful algal blooms is a major ecological concern resulting from nutrient enrichment from runoff.

While nutrient enrichment can also have other ecological effects such as negatively impacting biodiversity or affecting various types of water bodies, the promotion of harmful algal blooms is a direct consequence of the nutrient overload itself. Understanding this relationship is crucial for effective management of aquatic ecosystems and for mitigating the impacts of nutrient pollution.