Oxygen is the most important constituent of water body health. Oxygen is an essential element for all aquatic organisms that breathe. Therefore, there is a direct relationship between the oxygen concentrations and exchanges occurring in a water body, and the physiological status of aquatic organisms.
Without oxygen at the bottom of the water body, anaerobic bacteria (those that live without oxygen) produce acids. These acids not only increase acidity but also cause a massive release of phosphorus and nitrogen, two major fertilizers, from the organic sediment and into the water column. These same anaerobic bacteria put toxic gases in the water including hydrogen sulfide (that rotten egg smell), ammonia, carbon dioxide, and methane. These gases are all toxic to fish, beneficial bacteria and insects.
Lack of Oxygen in Water Bodies
Lack of bottom oxygen is the cause of odors produced by anaerobic bacteria.
These same anaerobes kill beneficial bacteria and insects that would feed on the bottom organic sediment and biodegrade it into carbon dioxide, water and a tiny amount of inorganic ash. This ash is beneficial in reducing acidity.
Lack of oxygen can cause fish kills or prevent fish from feeding on benthic (bottom feeding) insects.
Lack of fish enables disease-hosting mosquitoes to thrive, as mosquitoes are natural food for fish.
Anaerobic bacteria include many types of pathogenic (disease-producing) bacteria. These diseases include cholera, scabies, typhoid, shigella, salmonella, botulism and miscellaneous bacteria that cause infectious boils and sores.
Without oxygen at the bottom at all times, beneficial bacteria and insects cannot biodegrade the organic sediment. Large accumulations of organic sediment follow.
The concentration of dissolved oxygen found in a water body and available to the organisms, insects, fish, etc., is the result of many dynamic processes. The primary sources of dissolved oxygen are the atmosphere and photosynthesis. Oxygen-using processes, both biological and chemical, counterbalance these sources of oxygen. Any oxygen concentrations found in a water body at any specific time are the result of numerous dynamic changes.
The Importance of Oxygenating Water Bodies
The most important factor in getting oxygen to the bottom of a water body is that it must be done without mixing the nutrients in the sediment, and the anoxic water at the bottom with the water column by turbulent mixing. The toxic bottom gases must be removed without mixing them with the rest of the water body.
Oxygenating the bottom binds up to 97% of the phosphorus and nitrogen in the water to the bottom sediment where it becomes food for beneficial, muck consuming bacteria and insects. The insects then become one of the best foods for fish, improving fish growth, health and number.