What does the term pond scum refer to?

The term pond scum commonly refers to a dense, free-floating mat of filamentous algae. These algae thrive in nutrient-rich waters and can form thick layers on the surface of ponds, often giving them a greenish appearance. This growth can be a result of excess nutrients, particularly nitrogen and phosphorus, often from runoff or decay.

Understanding this phenomenon is vital in aquatic management because while some algae play a beneficial role in aquatic ecosystems, excessive growth can lead to oxygen depletion in the water, negatively affecting fish and other aquatic organisms. Effective management of pond environments often involves monitoring and controlling algal growth to maintain ecological balance. Hence, recognizing filamentous algae as pond scum helps in identifying potential water quality issues that need to be addressed.