Eli5: Was all the organic matter in the soil once alive?


Title says it all, is the organic part of our planet’s ground, the dirt/soil all of biological origin be it leaves or waste or flesh of plants and animals over many many many years? Or are there other ways some is formed through geological methods?

In: 1

Essentially, yes.

Soil is organic matter and rocks, sand, other inorganic materials, all smooshed together. But there’s lots of life in soil. It’s teeming with bacteria and fungi, breaking down and eating every little bit of remaining matter they can, releasing everything into the soil. Not to mention the worms, bugs, and other things that are in the soil.

So, it’s not just dead stuff and inorganic stuff, it’s also all the living things, ranging in size from moles, through earth works, down to nematodes, finally bacteria and fungi, that eat the organic matter in various stages of decay.

rocks are broken down by various processes and become available minerals for life constantly, the dead bodies of lifeforms become rocks by various processes too. Some early life ate rocks slowly and a huge unseen world of bacteria and archaea has continued to do just that for 3.5 billion years or so. The deep biosphere contains more mass of life than the ocean.

TaleThick answered it best, but basically any blackness (carbon) you see in the soil was once alive, and probably still is habitat for millions of microbes.