What are the common signs of an algal bloom in water bodies?

The presence of discoloration in water, often seen in shades of green, blue, or brown, along with foul odors, is a clear indication of an algal bloom. These blooms are caused by excessive nutrient enrichment, often from fertilizers or wastewater runoff, which leads to rapid growth of algae that can color the water and produce decay odors.

While clear water and healthy fish populations indicate a balanced ecosystem, they are not signs of an algal bloom. Similarly, overgrowth of aquatic plants may suggest overall vegetation growth but does not specifically indicate an algal bloom, as it is not exclusive to algal presence. Increased fish sizes are not a direct sign of a bloom; in fact, fish may be adversely affected by algal blooms, leading to reduced populations rather than growth due to the stress or toxins produced by harmful algae. Thus, foul odors and discoloration are the key indicators of algal blooms in aquatic environments.