By Sue Crowley, executive director
What a beautiful morning with just a dusting of snow to blanket the world with a fresh layer to explore tracks and other signs of beings moving about. I savor the absolute clean chill of the cold air as I take the first breaths of the outside air. Although a bit cliché, it is exhilarating and awakening.
I have been watching the pond by the Alyea lookout tower just behind the nature center. The water froze quite beautifully over this winter. I ventured out on the pond this morning and with the first tracks, it is quite exciting to swish away the snow to see what the ice looks like. On my way out, down the small path to east side of the pond, I disrupted about half dozen mourning doves taking refuge among the tangle of alders, twisted willows, red-osier dogwoods, and grasses. Out on the pond the clarity and texture of the ice is quite variable. I was hoping to still see the cool bubbles frozen in place. As luck would have it, I found an intriguing spot with an ash leaflet frozen in the ice as well (picture provided).
The ice bubbles are gas being released either from the water itself as oxygen or they may also be formed by the work of decomposers giving off methane. Also, consider that aquatic plants will release oxygen as well. I am not schooled enough to know if you can tell the difference between the two, oxygen or methane bubbles.
If you think about ice cubes in our freezers, most of us do not have crystal clear ice. The ice cubes tend to freeze from the top down thus pushing the gas toward the bottom or center and forming more cloudy or opaque cubes. Apparently, my cubes at home have a lot of gases to work with as you can see from the photo. The gas will coalesce and freeze, making the cubes opaque. I read about putting some water in a small cooler and freezing it. The top part will freeze clear free of bubbles and there should still be some liquid water in the bottom of the cooler. Pull out the top ice and you have crystal clear ice. I might just test this out this weekend.
Other variations come into play when there is a plant sticking out of the water and there appears to be ice ripples formed outward from the stem. So, whether you check out your ice cubes at home or get outside and explore the frozen waters of winter, just know that those ice bubbles were trying to escape and were being pushed down by the ice. The bubbles or ripples in a pond or wetland are interesting and beautiful to see the variety of different shapes and formations- nature’s abstract art!
Photos by Sue Crowley