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Pond Aeration Systems THE BENEFITS OF POND AERATION The purpose of aeration is to provide additional oxygen and circulation to a pond, lagoon, or water garden. This input translates into a multitude of benefits for the pond’s water quality and the organisms that live in the water or those that use the water. BACKGROUND OXYGEN IN ATMOSPHERE • Air contains approximately 20% oxygen (O2), 80 % nitrogen (N2) and a variety of other gases, including carbon dioxide (CO2). These amounts vary depending on altitude above sea level and other factors, such as natural geological forces, meteorological conditions, and human air pollution. PROBLEMS WITH PONDS HAVING LOW OXYGEN CONCENTRATIONS • Water contains varying amounts of oxygen, ranging from zero to over 10 ppm (mg/l), depending on the pond’s ecological condition. If the pond is a “dead” or “dying” pond, the amounts near the bottom are zero, or close to it. In this zone the pond’s bacteria slowly convert organic matter into CO2, H2O, and minerals. In addition, these conditions support and encourage pathogenic bacteria, or various disease organisms, which are detrimental to a healthy pond and desirable fish populations, such as bass or trout. • This condition is often accompanied with the production of hydrogen sulfide, giving the air a putrid smell of rotten eggs! • Further problems can occur in colder climates with deeper ponds and lakes, when a natural temperature stratification of the water column develops in the spring and fall. In this situation the fish congregate in the lower zone of the pond, called the hypolimnion, where oxygen from the atmosphere does not circulate or make up for oxygen used by fish and other organisms. Fish can survive these conditions if the pond is healthy and the stocking rate is not too high; however, they can be severely stressed or killed if the oxygen level becomes too low! • In addition, fish can also be stressed or killed when ice cover prevents atmospheric mixing with the water! • Fish kills are also common during late summer or early fall in those lakes where organic buildups result in massive algae blooms and associated drops in oxygen. BENEFITS FOR PONDS HAVING PROPER OXYGEN CONCENTRATIONS • The most subtle and important benefit of proper pond aeration is the improvement of conditions in the pond bottom. In this zone, the pond’s bacteria become energized and empowered, so they can properly digest and clean up the organic sludge coating the pond’s bottom. Proper aeration also provides proper conditions for introduced bacteria and enzymes to supplement and empower the resident bacteria. Taken together, the pond is now in position to establish and maintain a proper ecological state for the fish and other aquatic life. • As a result of the infusion of oxygen with the aeration, the pathogenic bacteria are pushed to a subordinate position by the aerobic bacteria. Accordingly, the threat to the health of fish and other aquatic life is lessened and the probability of a healthy fish population is enhanced. • With proper aeration in the pond, the oxygen-loving bacteria can now dominate the bottom environment and digest the organic buildup from the algae, fish, terrestrial plants, and other land and aquatic life forms. When this occurs, aquatic plant nutrients are processed and less of them are available for the use by nuisance algae. • Additional benefits accrue from displacing those bacteria that do not use oxygen for their life processes. Of particular importance are the sulfur bacteria, which produce the hydrogen sulfide and the smell of rotten eggs! • Improved aeration also benefits the food chain, which is so important for sustained a desired fish population in a pond. In particular, it enhances the production of aquatic insects and smaller fish, who have sufficient oxygen for growing and reproducing. • When a pond stratifies, due to depth and colder temperatures, aeration helps by circulating the water and breaking up the thermal barrier, called a thermocline. This condition results in higher concentrations of oxygen at the lower levels of the pond, and proper conditions for resident populations of fish. • Proper aeration can also reduce or eliminate fish kills, resulting from oxygen depletion in late summer or early fall. • And it also reduces or eliminates fish kills, caused by ice cover, low oxygen, and high populations of fish |
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