What can result from overloading a waterbody with wastewater?

Overloading a waterbody with wastewater can lead to low dissolved oxygen levels due to several factors. When excess nutrients, particularly nitrogen and phosphorus, enter the water, they stimulate algal blooms. This rapid growth of algae can create a dense surface layer that blocks sunlight, affecting aquatic plants' ability to photosynthesize and produce oxygen.

When the algae eventually die, they sink to the bottom and are decomposed by bacteria, a process that consumes a significant amount of oxygen from the water. This depletion of dissolved oxygen can create hypoxic conditions, making it difficult for aquatic life, particularly fish and other aerobic organisms, to survive. Therefore, low dissolved oxygen levels are a direct outcome of the excessive nutrient load from wastewater, leading to impaired aquatic ecosystems.

In contrast, options such as increased fish populations, enhanced water clarity, and reduced algae growth would not typically occur as a result of wastewater overloading; instead, they represent conditions generally favorable to aquatic life and water quality.