Key takeaways for pond aeration:
- Aeration devices create turbulence that facilitates water mixing with the oxygen-rich atmosphere. Fountains are most popular for aesthetics, but “pond bubblers” are more effective for moving water and oxygen throughout the water column and cost less.
- Dissolved oxygen in the water column (not just the surface) is essential to the beneficial biological and chemical processes that keep pond life in a healthy balance. Dissolved oxygen is critical to fish and other aquatic life.
- Ponds with high nutrients are more vulnerable to undesirable algae blooms.
- Circulation and aeration oxidize and hasten phosphorus removal.
- Aeration supports aerobic bacteria that utilize nutrients and decompose organic matter.
- Bottom-pond aeration is used to maintain oxygen concentrations throughout the entire water column.
- Even shallow ponds have temperature stratification during the season.
- The oxygen-carrying capacity of water varies with temperature (cold water carries more oxygen). Use aeration to increase dissolved oxygen (DO) before levels are low and algae blooms occur.
- Oxygen diffuses into the water from the atmosphere and is produced by aquatic plants and algae. Oxygen is also consumed by bacteria during the decomposition of organic matter.
- Dissolved oxygen stimulates the chemical reactions that cause metals to discharge out of the water and into sediment. They bind with phosphorus and other nutrients that make them unavailable to plant use.
- Anaerobic bacteria thrive with low oxygen concentrations, facilitating reactions that release metals and nutrients back into the water column that become a source for algae growth. The “bottom” layer or benthic zone contains the decaying organic material and sludge. Anaerobic decomposition creates methane and hydrogen sulfide gases that cause harmful odors and gases.
- Warm surface waters carry the highest concentrations of oxygen. As temperatures decrease in deeper waters, oxygen levels decrease as well. In the summer months, “turn overs” disrupt stratification, allowing oxygen-poor water and nutrients to quickly move to the surface. This creates rapid and excessive growth of algae and increases fish kills.