The seafloor is turned over
Burrowing animals destroy the microbial mats that had carpeted the world's oceans for three billion years.
- When
- —
- Duration
- 18 million years
- Known to
- ± 5 million years
- Era
- Cambrian, Paleozoic
As animals dig deeper and more vertically, the firm mat-bound seafloor of the Proterozoic gives way to soft, churned, oxygenated sediment. Organisms that had rested on mats must adapt or vanish, while a whole new infaunal habitat opens below the surface. The mixing also changes the chemistry of the sediment-water interface, altering how carbon, phosphorus and sulfur cycle through the ocean.