A team of Chilean and Smithsonian Institution researchers traveled Chile's Atacama region to investigate one of the world's best preserved graveyards of prehistoric whales and other marine organisms. After investigating the place, scientists pointed towards toxins generated by algae blooms to be behind deaths of animals that took place millions of years ago.

The paper, 'Repeated mass strandings of Miocene marine mammals from Atacama Region of Chile point to sudden death at sea', has been published in the journal Proceedings of the Royal Society B.

It was in 2010 that Cerro Ballena or Whale Hall was discovered. It consists of at least 40 dead whales and an array of other extinct species. Scientists said a deadly neurotoxin produced by algae would have been ingested or inhaled by marine animals.

Lead author of the study, Nicholas Pyenson of the Smithsonian's National Museum of Natural History, said there are chances whales could have died after eating animals that fed on algae.

May of the whale skeletons were found belly-up and it gave a clue that they have died in the sea. Even bodies of dead whales ashore quickly. "These big hunks of meat stranded on a tidal flat, yet there were no terrestrial predators like a bear, nothing really larger than a dog, that could dismember the carcasses and carry the bones away", said Pyenson.

Pyenson said when they saw collection of wide fossils like different whale species, marlins, seals and an aquatic sloth and then they realized that it could not be an illness or a virus. It had to be something that had affected them all.

If poison created by algae blooms is ingested or inhaled then it causes organ failure in marine mammals. Algae blooms can be found commonly along coasts. Sophisticated photography and laser scanners were used to come up with an online archive of 3D images of the whales.