Ice bubbles
I discovered these fascinating ice bubbles on the shoreline just as the lake was freezing over for the season.
The best explanation I can find is that frozen bubbles like these form when plants and tree limbs on the bottom of the lake start decaying. During this process methane gas is released, creating bubbles in the water. When the air temperature drops, often quickly in the winter months, these methane bubbles become trapped in ice, and can cling on the water’s edge or be suspended just below the surface of the water.
As water approaches its freezing point (32 degrees F / 0 degrees C) it becomes less dense than the water around it and rises to the top of the surrounding water. Under calm conditions, ice freezes on lakes very similarly to how it freezes in an ice-cube tray. Lake ice freezes first at the surface, always starting at the edges or shoreline. Water near the shore is shallower and contains less heat than deeper water so it reaches the freezing point faster than deeper water.
These ice bubbles were perfectly clear and almost looked like soap bubbles, as if they would pop with the lightest touch. The way they clung to the shoreline and almost looked stretched and elongated was especially fascinating.
As lakes freeze and ice sheets tighten and shift, a distinct moaning noise can emanate from the lake, as well. This moaning is most evident at night as the temperatures drop well below freezing. It reminds us that lakes are alive and constantly changing and moving, based on weather and currents below the ice surface.
The science behind nature often yields such fleeting beauty.