Alkalinity refers to the capacity of water to neutralize acids, which is important for maintaining a stable pH level. It is primarily determined by the presence of bicarbonate, carbonate, and hydroxide ions. High alkalinity can help buffer changes in pH, making water less susceptible to becoming acidic. In natural water bodies, such as rivers and lakes, alkalinity plays a crucial role in supporting aquatic life. It helps protect organisms from harmful fluctuations in acidity, ensuring a healthier ecosystem. Monitoring alkalinity is essential for water quality management in both natural and man-made environments.