This is Abraham Lake, on the North Saskatchewan River in western Alberta, Canada. The lake is filled with patches of bubbles -- evidently methane released by plants growing in the river -- that have been trapped over time as the river slowly turns to ice each winter. The patterns are fascinating, and provide a wonderful foreground for photography, particularly where the ice is clear and free of snow. Speaking of which, not long after I arrived and captured this image, it began to snow. By morning the bubbles were buried under nearly a foot of the white stuff, bringing the photographic portion of the trip to a halt. To obtain sharp focus from front to back in this near-far composition, I took seven shots, each focused at a different distance, and then seamlessly combined the sharpest parts of each using Helicon Focus software.