The Lake in Winter

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. A lake’s “winter” season is not usually associated with December 21^st to March 21^st, but is often based on the dates that the lake becomes fully ice covered. Once the surface of the lake is frozen, the entire ecosystem under the ice changes to cope with the colder temperatures.

The microscopic animals (zooplankton) and photosynthetic organisms (phytoplankton) produce thick-walled resistant cells, which allows them to survive until spring. Some species of cyanobacteria (blue-green algae) can survive at the cold temperatures by become cannibals and consuming other algae species for food they will not get from the sun. It is unlikely that they will form blooms since the conditions are not ideal, although it is not impossible.

If the algae do not completely become dormant, they may actually produce oxygen, which would be beneficial to the fish, who also share this space under the ice. If not, fish normally 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, their metabolism slows and 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. The main body of the plant dies, but the roots can survive. Some will form nodules, which can store energy while they wait for the sun to reappear. However, if they are exposed to the cold air, they may dry out and even the roots can then freeze. Lakes who perform a winter drawdown use this behavior as a method to reduce nuisance plants.

The most important aspect of the lake in winter is ice thickness. Remember, it may look solid, but with 450 acres of surface area, conditions may differ from one location to another. Some residents may use “ice cutters”, resulting in open water even if the rest of the lake is frozen. If you do venture out on the ice, use extreme caution and don’t do it alone.

(Some information presented in this article was extracted from Lakeline Vol 34, #4 (2014))

BE LAKE RESPONSIBLE And HAVE A HAPPY HOLIDAY SEASON