The transition from a dry, air-filled chamber to a flooded one was the event that began the twelve-thousand-year preservation that the cave diving team eventually discovered.

The cave has been flooded ever since.

The bones have been underwater for most of the intervening millennia.

And the water that covers them — cold, chemically stable, shielded from the UV radiation and the surface-driven processes that attack organic material — has done the same thing for the bones of Naia that it did for the bones of the megafauna: it has kept them from the dissolution and decay that would otherwise have returned them to the earth long ago.

She has been underwater for approximately twelve thousand years.