Aeration

Aeration is the process of adding oxygen to water. Maintaining healthy levels of dissolved oxygen (DO), one of the most, if not the most important water quality parameter, in your pond aids in the breakdown of decaying vegetation and other sources of nutrients that enter your pond. This breakdown of bottom silt is carried out by microorganisms at the water/soil interface and continues to proceed a few centimeters deep in the soil. This decomposition can be carried out in two ways, aerobically and/or anaerobically. Aerobic decomposition requires a continuous supply of oxygen and proceeds more rapidly as dissolved oxygen concentrations near saturation levels. The rate of degradation of organic matter in anaerobic conditions is not as rapid as under aerobic conditions, and the end products are organic compounds, such as alcohols and foul-smelling organic acids (the sulfury pond muck smell!). In other words, the decomposition is slower and less complete in anaerobic environments than in aerobic habitats where the primary end product of decomposition is carbon dioxide. So what we can learn from this is, the more decomposition we can facilitate, through the addition of oxygen with aeration, the less nutrients there will be available for algae blooms and excess aquatic plant growth.

In ponds, the introduction of oxygen via some type of aeration device can:

  • Allow for greater densities of fish.
  • Eliminate the potential for Spring and Fall turnover.
  • Prevent wither kills caused by low oxygen levels.
  • Improve overall water quality.
  • Speed up the rate of organic decomposition.
  • Reduce the amount of phosphorus, which would otherwise be available for plant growth.
  • Thermally and chemically destratify the water.
  • Cause circulation currents that might create favorable conditions for more desirable algae to out compete blue green algae.
  • Decrease the severity of algae blooms and algae die-offs.
  • Shift the level of carbon dioxide by venting it into the air, which could limit the amount available for plants.

Each pond, lake, or body of water is unique and not each method or application of aeration will work in each pond. It is important to talk to someone who has experience and knowledge of aeration devices to help decide which method is best for you.

There are two types of aeration, surface and sub-surface:

  • Surface aeration is usually a fountain type system that creates a surface disturbance and provides oxygen transfer. Surface aeration is the most important factor in controlling duckweed and watermeal. A disturbance must be created on the surface of your pond to cause an environment in which these fragmenting aquatic plants cannot thrive. Duckweed and watermeal must have flat stagnant water to flourish.
  • Sub-surface aeration is a diffused air system or commonly known as a “Bubbler”, this type of aeration is used when water depths are greater than 6 ft. This system will also raise oxygen levels, which is key in breaking down nutrients. This nutrient reduction is directly related to controlling filamentous algae and other sub-surface aquatic plants.

Surface Aerator

Aerating Fountain

Sub-Surface Aerator