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When I die, what happens to my microbiome?

Luce Gilmore
Cambridge, UK

The fate of one’s post-mortem microbiome is chaotic and messy. Most of the microbiome resides in the gut, and the gut is quite anoxic, so one’s ceasing to breathe isn’t instantly calamitous. Of course, there is no more food coming in, but the body’s containment machinery, built into the gut wall, rapidly fails. Suddenly, the food upon which the gut microbiome subsists becomes the gut itself.

There is no way to put this delicately. The gut microbiome dissolves the gut wall and goes on to consume the corpse. The first visible sign of this is a greenish tinge appearing in the lower right quadrant of the abdomen. There are bound to be winners and losers in the microbiological rout. In particular, the obligate anaerobes will perish as the body wall loses integrity and grows permeable to oxygen.

There is no way to put this delicately. The gut microbiome dissolves the gut wall and goes on to consume the corpse

Entropy will triumph. Bacteria that were beneficial food processors, such as butyric-acid fermenters, will give way to the catabolic wrecking crew that smashes anything breakable into carbon dioxide, water and ammonia. So (as Kurt Vonnegut said) it goes.

John Wilkinson
Via email

It all depends what happens to your body. If you are cremated, your microbiome goes up in smoke along with you. If you are buried in the cold, cold earth, then it pretty much shuts down. But if you lie in a moderate temperature, it eats you. It’s called decomposition!

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