New Delhi, June 11 -- Scientists have unearthed communities of marine life - including jellyfish, tubeworms and brittle stars - thriving on a millions-year-old whale graveyard.

These graveyards form when whale carcasses fall to the sea floor, becoming a sustaining snack for nearby critters. This one, located up to 23,000 feet (7 kilometers) below the surface of the southeastern Indian Ocean, spans the largest area and is so far the deepest and oldest found.

A whale's sheer size and the unique chemistry of its bones are the keys to forming these unique underwater neighborhoods, said Xikun Song, a biologist with the Chinese Academy of Sciences' Institute of Deep-sea Science and Engineering.

"At the same time, the very nature of the deep ...