Why is low dissolved oxygen (DO) in water a concern?

Low dissolved oxygen (DO) levels in water are a concern primarily because they are essential for the survival of aquatic life. Many aquatic organisms, including fish, invertebrates, and microorganisms, rely on dissolved oxygen to carry out respiration, which is vital for their metabolic processes. When the levels of dissolved oxygen drop below what is necessary for these organisms, it can lead to a state known as hypoxia, which can result in stress, decreased reproduction, and even death of aquatic species.

Sustaining adequate levels of dissolved oxygen is critical for maintaining healthy ecosystems in water bodies. High levels of organic matter decomposition, often due to pollution or nutrient loading, can consume available oxygen, further exacerbating the issue. Therefore, monitoring and managing DO levels is a key component in ensuring the health and sustainability of aquatic environments.