JuanJuan Dissolvod Oxygen+DO08/DO09

Dissolved Oxygen (DO) refers to the amount of oxygen gas (O ) dissolved in water, typically measured in milligrams per liter (mg/L). It is a critical parameter for assessing water quality and the health of aquatic ecosystems.

Oxygen enters water primarily through diffusion from the atmosphere and as a byproduct of photosynthesis by aquatic plants and algae. The solubility of oxygen is influenced by water temperature, salinity, and atmospheric pressure; cold, fresh water holds more oxygen than warm, salty water.

DO is essential for the survival of most aquatic organisms, including fish, invertebrates, and bacteria, which rely on it for respiration. Consequently, DO levels directly determine the types of species an aquatic environment can support. Healthy, well-oxygenated waters typically have DO concentrations above 5-6 mg/L. Levels falling below this range can stress aquatic life, leading to fish kills and a shift to species tolerant of low oxygen (hypoxic) conditions.

Significant drops in DO, a phenomenon known as deoxygenation, are often caused by excessive nutrient pollution (eutrophication). This fuels algal blooms, whose subsequent decomposition by bacteria consumes vast amounts of oxygen. Therefore, monitoring dissolved oxygen is fundamental for managing wastewater, controlling pollution, and protecting fisheries. It is a key indicator used by scientists and environmental agencies worldwide to safeguard the vitality of our rivers, lakes, and oceans.