What does turbidity measure in water samples?

Turbidity is a measurement of the cloudiness or haziness of water, which is primarily caused by suspended particles such as silt, clay, organic matter, and even microorganisms. These particles scatter and absorb light, making the water appear less clear. Monitoring turbidity is crucial because it can indicate water quality and the possible presence of pollutants or other harmful substances in the water. High turbidity levels can also affect aquatic life by reducing light penetration, which can impede photosynthesis in aquatic plants and disrupt ecosystems.

The other options focus on different aspects of water quality: dissolved oxygen is essential for aquatic life, temperature influences biological processes in water, and the presence of microorganisms can indicate contamination or health risks but is not what turbidity specifically measures. Thus, recognizing that turbidity directly translates to the cloudiness or haziness of water confirms why this option is correct.