Ever notice what looks like tiny bubbles breaking on the surface of your lake or pond when the wind is calm? I notice them because I used to trout fish a lot.
Festooned in all things Orvis®, my fishing paIs and I would hit the trout streams of West Michigan regularly and make pilgrimages north to the Au Sable and Betsy rivers — “The Holy Waters.”
To trout fishers, bubble-like disturbances mean an insect hatch is happening; midges, caddis, and the fabled, Hexagenia Limbata — trout feed on whatever’s hatching. We’d quickly “match the hatch” with dry flies, (fly rods only — no “crank baiting”). We were trout purists. We always looked for hatch bubbles.
Years later I owned a lake cottage. One calm evening, I noticed hundred of bubbles breaking the surface, so I went to investigate; old habits die hard.
To my surprise NOTHING was hatching. The bubbles were rising from the lakebed itself — I had no clue what this was — but I was determined to find out. And so I did.
Mystery of the Bubbles Solved!
They’re methane gas! The same natural gas used to heat homes and cook on gas stoves. But why is methane in your lake?
Organic matter; dead plants, fish poop, leaves and so forth, are digested by bacteria. Organic matter on the bottom is digested by aerobic bacteria — which expel methane gas as a byproduct.
Organic matter under mucky bottoms is digested by anaerobic bacteria, which produce hydrogen sulfide as a byproduct. Methane is odorless. Hydrogen sulfide smells like rotten eggs. They’re both highly flammable.
If a lake or pond freezes over, these gases are trapped under the ice until the spring thaw… Or until you poke a hole in the ice and light the gas on fire.
Admit it. This looks like a lot of fun, doesn’t it?
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