Beautiful, noisy ice.

DSC_0741Winter in Iowa (even the most southern portions of the State) often includes frozen wetlands. I visited Mount Ayr Wildlife Management Area in Ringgold County recently, and walked out on the ice…and experienced a sensory assault I won’t soon forget!

It doesn’t seem like it should be such a big deal, especially on a pleasant, calm day. I made quite sure that the ice was very thick, solid…and safe. Nevertheless, I am mindful that I am walking on a layer of frozen water, floating above very cold, liquid water. It makes me a bit uneasy. This mild anxiety is heightened by the sloshing of water, overheard from nearby  fountain-type aerators at an opening in the ice. I presume the wetland managers want to keep open water available for wildlife during the winter (especially waterfowl)? I didn’t see any such wildlife, although I did see the droppings on the margin of the ice, near the open water. Anyway, seeing the open water made me look more carefully at the ice cover. I was certainly suspicious about its integrity.

DSC_0733More disconcerting than the sloshing, is the sound of the ice breaking. Once in a while, my footstep resulted in a cracking of the ice; this becomes visible, with vertical cracks in the ice looking much like veins in a marble floor. That cracking sound is quite noticeable on a quiet day. Once in a great while, the ice cracks with a sound like a rifle-shot…really loud, and certainly unsettling!

But for all that, the ice is truly beautiful: it scatters light like a giant crystal, it has trapped bubbles or plants creating striking shapes and textures; it has clear window-like parts with a good view to the water below. Even the animal droppings on top look interesting as they absorb sunlight, warming the ice and melting it, slowly sinking into the surface.

DSC_0742No doubt, many plants, animals and microbes of the wetland were still there on that wintry day, and very much alive. When I worked at a nature center, we taught children about three strategies for organisms facing the challenge of winter: “take off, take a nap, or just take it.” Despite the open water and bird droppings, we know many birds in our area do in fact migrate south to warmer climes for the winter. But much life is right here, in the mud at the bottom of the pond, or in a den, or just sluggishly moving through the water itself beneath the ice. Some plants I found poking up into the air, and they may also have roots or stems or buds down below, waiting for Spring.

I used a giant drill (an auger) to make a hole in the ice, and collected a sample of water from below. Back in the lab, I did indeed find tiny swimming animals (microcrustaceans like Copepods and Ostracods), Duckweed, and other life too. I’ve always been impressed with how the dormant plants, animals and microbes under the ice perk up quickly at the lab.

It’s important to work the science of aquatic ecology. But I hope you’ll also allow me to simply admire all that beauty in our icy, wintry wetland. And…on those sometimes dark, bitterly cold winter days of your life, take strength from these hearty wetland residents, and cheer up. Spring will find us, eventually.

Author: Paul Weihe

Associate Professor of Biology at Central College, traditional author (Textbook of Limnology, Cole & Weihe, 5th ed.; Waveland Press), and now...blogger!

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