The Lake – A Winter Wonderland?
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.
Of most importance to many of our residents is the effect on the fish population. For a deep lake like ours, it is unlikely that it will become completely frozen. Even with the drawdown, there are ample areas in the lake that are deep enough so that the fish can find refuge. 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, which will protect them in a dormant state until conditions are more favorable. Although they may survive the cold, the populations likely are reduced during the winter.
This winter is expected to be much colder and experience more snow than the El Niño we saw last year. This could extend the “winter season” seen for the lake. Even though this may result in more and thicker ice formation (if the almanac is correct), please follow the various ordinances (e.g. no snowmobiles on the lake) 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))
BE LAKE RESPONSIBLE