What is one consequence of excessive nutrient inflow in aquatic systems?

Excessive nutrient inflow, often stemming from fertilizers, wastewater, and runoff, leads to a phenomenon known as eutrophication. This process results in an overabundance of nutrients, particularly nitrogen and phosphorus, in aquatic ecosystems. As these nutrients accumulate, they promote rapid algal blooms. While algal blooms might initially seem beneficial, they can have severe and far-reaching consequences.

One significant consequence is the decreased aquatic biodiversity. As the algal blooms proliferate, they consume the available oxygen in the water during their decay, leading to hypoxic or anoxic conditions where oxygen levels drop dramatically. Many aquatic organisms, including fish and invertebrates, cannot survive in these low-oxygen environments, resulting in decreased populations or even local extinctions of sensitive species. Furthermore, the dominance of certain algal species can outcompete native plants and organisms, altering the ecosystem dynamics and further reducing biodiversity.

In contrast, options such as improved water retention, increased fish population, and better water clarity do not accurately depict the consequences of excessive nutrient inflow. In fact, nutrient overload typically leads to poor water clarity due to the dense blooms and can hinder the growth of submerged aquatic vegetation, which is vital for providing habitat and food for diverse aquatic life.