Most odors from ponds are caused by:

• A. Algae
• B. Overloading
• C. Infiltration
• D. Toxicity

Answer: (B)

Odors from ponds come mainly from anaerobic decomposition that happens when the pond is overloaded with organic matter. When there’s more waste entering the pond than it can aerobically treat and mix, the bottom waters become oxygen-poor. Bacteria break down the accumulated organic material in this lack of oxygen and release foul gases such as hydrogen sulfide and ammonia, which create the characteristic smell. Algae can contribute to odor when blooms die and decompose, but the dominant source is the excessive organic loading that drives anaerobic conditions. Infiltration doesn’t generate odors by itself, and toxicity isn’t the primary cause of typical pond odors.