Does Water Temperature Impact Lake Oxygen Levels?

The primary effect of high temperatures on lakes and ponds is dissolved oxygen depletion. Dissolved oxygen is vital for balanced aquatic ecosystems. Native plants, fish, beneficial bacteria, and other organisms require oxygen to function and thrive. Unfortunately, as temperatures increase, water loses its ability to contain gases. Oxygen molecules move faster, allowing them to escape into the atmosphere.

Fish kills are a common sign of dissolved oxygen deficiencies. If fish do not have sufficient oxygen to respire, large populations may die off in a short period of time. Before this occurs, stakeholders may notice fish swimming erratically or congregating at the surface of the water, gasping for air. This is particularly common after a long string of intensely hot, sunny days.

Another symptom of oxygen deficiency is muck build-up. Poor dissolved oxygen levels can inhibit the natural decay of plants and organic matter. As muck accumulates over time, the waterbody may lose depth and volume, potentially resulting in dangerous flooding or shoreline erosion. Stakeholders should keep an eye out for signs of muck accumulation, such as muddy-looking water or foul “rotten egg” odors.

Dissolved oxygen plays an important role in maintaining the equilibrium of aquatic environments. Balanced water quality helps cultivate a healthy food web. In turn, algae and plant populations are kept in check without overcrowding the ecosystem. However, the complex food web can be disrupted when dissolved oxygen levels drop. For example, if a fish kill occurs, aquatic weeds and algae will no longer be consumed. Infestations of aquatic weeds, slimy mats of algae, and scummy, green cyanobacteria (toxic blue-green algae) are common signs of insufficient oxygen. Furthermore, without intervention, nuisance growth can exacerbate water quality imbalances and accelerate muck accumulation.

Luckily, there are many ways to restore and maintain dissolved oxygen at healthy levels. Floating fountains and surface aerators can be used to continuously circulate the surface of the water. Most effective in more shallow waterbodies between 4-8 feet deep, these tools agitate and mix the water, facilitating the transfer of oxygen from the air into the water. Floating fountains are also designed with unique spray patterns and lighting features to add visual interest. Surface aerators are designed for maximum functionality and can also be enhanced with lighting features. 

Submersed aeration is another solution to help increase dissolved oxygen in lakes and ponds greater than 6 feet deep. Placed on the floor of a waterbody, submersed aerators pump surface air to the bottom through specialized tubing. The air is released through a diffuser into fine bubbles that help oxygenate and circulate the water as they rise to the surface. To achieve maximum benefits, Aquatic Experts may recommend placing a submerged aerator under a fountain or surface aerator.

Submersed aerators are particularly beneficial for waterbodies that suffer from stratification, the natural formation of distinct water layers known as thermoclines. Each layer has a different temperature and dissolved oxygen level, with the warmer, oxygen-rich layers forming closer to the surface. When these layers mix rapidly with colder, oxygen-deficient layers at the bottom during a rainstorm or other weather event, the sudden fluctuation in temperature and oxygen can stress aquatic life and lead to fish kills. By continuously circulating water, submersed aerators help prevent thermocline formation, promoting a more stable and oxygen-rich environment throughout the waterbody.

Supplementing dissolved oxygen is not the only way to maintain balanced water quality. Aquatic experts often recommend nutrient remediation services for oxygen-deficient lakes and ponds. This typically involves applying eco-conscious materials that are designed to bind with or “de-activate” the nutrients that sustain weed and algae growth. By inhibiting nuisance growth, this process can help restore the equilibrium of the food web. A variety of nutrient remediation products are available based on the size, depth, and function of your waterbody. An experienced Aquatic Expert can help you make the right selection for your lake or pond.

Muck is a significant source of excess nutrients. Biological bacteria are responsible for breaking down dead plants and organic matter, but cannot function without dissolved oxygen. In some situations, beneficial bacteria can be supplemented to improve the decomposition process. In other cases, new, environmentally friendly products like TryMarine can be applied to dissolve bottom muck, leaving behind sand and freeing up oxygen to be reabsorbed into the ecosystem. Once the process is complete—often, within 3-6 months—stakeholders should see measurable water quality improvements, with up to a 50% decrease in nutrient levels. TryMarine’s NSF-60 certification confirms it is safe for use in all types of waterbodies, including drinking water reservoirs.

In severe cases, more significant intervention may be required to reestablish balanced water quality. Physical removal of oxygen-depleted bottom muck, some aquatic weeds, and other organic materials can be conducted through mechanical hydro-raking. Eroded shorelines may also need to be repaired to prevent further sediment accumulation. This may involve rebuilding and anchoring the shoreline with bioengineering materials. Introducing native shoreline vegetation around the perimeter can add additional stability and help filter stormwater runoff, which picks up nutrient-rich organic matter as it flows toward lakes and ponds.