To understand why pond and lake aeration is important, it is necessary to understand the role of oxygen in a lake, particularly a fishing lake or pond, for when we are talking about aeration, we are talking about adding oxygen. There is more than one way oxygen is added to a body of water. The most important reason for proper oxygenation is that fish need oxygen to breathe.
Oxygen is added to the lake as a byproduct of photosynthesis by aquatic plants. Photosynthesis is the process of creating carbohydrates (green vegetation) by using light as the energy source, carbon dioxide, and water as initial ingredients to the process, and releasing oxygen as a byproduct.
The amount of dissolved oxygen in a lake or pond is an indicator of the health of the body of water. While some oxygen comes as a byproduct of photosynthesis, other oxygen is added at the interface of "sea and sky" so to speak, where the air meets the upper surface of the water and a certain amount of oxygen is absorbed at the interface. Again, even this quantity can be affected as a rough, choppy, windy day allows more opportunity to "mix" air with water than a calm, windless day.
There are problems when oxygen is used faster than it is produced or absorbed. Certain problems that result are:
- Temperature differences occur between the top and bottom of the lake and reduce oxygen at the lower levels, which some fish may prefer to inhabit in the hot summer days.
- Fish can not breathe without oxygen; mass fish kills become possible.
- Non-oxygen requiring bacteria, anaerobic bacteria, breakage organic refuse and create toxic gasses, one of which is hydrogen sulfide.
- Fewer organic wastes are broken down in the absence of oxygen; this lead to increased bottom muck.
- Algae grows faster in low oxygen environments as it feeds on the increased nutrients in the muck. This detracts from the crystal clear lake.
Adding oxygen helps break down organic matter. This organic matter contains nutrients and they are part of the "muck" residing at the bottom of the lake or pond. Not only do these nutrients feed the algae, it is unsuitable to swim or wade in a mucky lake or lake shoreline with a lot of algae. As the muck is broken up, and the nutrients are reduced, both the muck and algae growth is reduced, making for a more pleasant lake or pond.
Oxygen can be added through aeration systems. This helps reduce the stratification, balance the pH, and give fish the oxygen they need at all levels and depths through the year.