concept

Bioturbation

Living things digging, boring, pushing and mixing sediment - roots, worms, burrowing animals - blurring or erasing the layering the sediment had just acquired. In tropical forest soil, bioturbation runs continuously and hard enough not only to break up brittle bone but to destroy sequence itself: even the accidental order of who was buried before whom gets scrambled. Ironically, it is biological activity that erases the record of biology.