Why Does Your Lake or Pond “Bubble?”

Why Does Your Lake or Pond “Bubble?”

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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