Heat of the Summer can be Hard on Lakes


The hottest days of the summer are officially here.  Longer days, bright sun, and high ambient temperatures cause surface waters to gradually increase to a point where it can no longer mix with cooler bottom waters.  This ‘thermal stratification’ stops the transport of nutrients and oxygen between these layers.  As water temperatures increase, its capacity to hold dissolved oxygen decreases.  Lower oxygen conditions develop making the late summer a particularly tough time for fish.  Something as simple as an algae bloom or a thunderstorm can easily lead to a summer fish kill.  

Subsurface aeration is the best way to eliminate summer stratification.  The laminar flow created by the rising column of bubbles transports oxygen depleted bottom water to the surface while stabilizing dissolved oxygen levels.  While subsurface aeration is the best way to protect fish from summer die offs, care must be taken when starting an aeration system in the late summer.  August seems to be the most prevalent time of year to see a fish kill related to the installation of a new aeration system.  Marginal ponds with high levels of organic material tend to be more prone to aeration related fish kills due to the upwelling of organic particulates.  Slowly incorporating aeration in the late summer has proven to be a safe strategy, starting with one hour of run-time the first day, and doubling the runtime every day until you are aerating full-time.