The Lake – A Winter Wonderland?

By David Ernes – Lake Management Committee

A frozen lake is just one more sign that winter has come to Roaming Shores. It presents a frozen snapshot of the beauty of the lake that has an almost alien quality to it. But have you ever wondered what is going on under the ice? A lake’s “winter” season is not usually associated with December 21st to March 21st, but often based on the dates that the lake becomes fully ice covered. There are some indications that the length of this winter season is becoming shorter with time, although linking this with climate change is a subject of much debate. Regardless, once the lake is frozen, the entire ecosystem changes to cope with the colder temperatures.

The most importance to many of our residents is the effect on the fish population. Fish seek the warmer waters under the ice and can survive as long as the oxygen levels in the water are adequate. They likely migrate to the sections in the lake that are the deepest, to have the best chances for survival. Since they are not warm blooded, they have several mechanisms to survive. Some can actually store fat and use it for energy. Also, their activity level decreases, requiring less energy to survive. This continues until the ice melts and the water starts to warm up again.

Aquatic plants can actually handle the winter better than their terrestrial cousins if they are protected under the water. Some will form nodules, which can store energy while they wait for the sun to reappear. Some may go dormant. However, if they are exposed to the cold air, they may dry out and then freeze. Lakes, who perform a winter drawdown as we have done this year and last, use this behavior as a method to reduce nuisance plants.

As far as algae are concerned, they are once again shown to be very adaptable. Some species can survive at the cold temperatures by become cannibals and consuming other algae species for food they will not get from the sun. Cyanobacteria (aka. blue-green algae) are one group of algae that can actually form a “resting cell” or cyst, much like a cocoon, that will protect them in a dormant state until conditions are more favorable.

This winter may be unusual as we are expecting an impact by an El Niño. If this happens, a warmer winter could significantly reduce the length of time that the lake is completely frozen over. It could also potentially impact the ice depth and it’s strength. Therefore, it is suggested that you be very diligent if you plan on doing any activities on the ice surfaces. Please follow the ordinances (mentioned in the latest “The Shores News”, page 3) regarding activities on the lake for your safety.

Like us, the lake and its many residents slow down their activity during the cooler winter months. But the lake is still an active environment, even if we cannot see it.
(Information presented in this article was extracted in part from Lakeline Vol 34, #4 (2014))

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