Scientists Solve the Mystery of a Nine-Million-Year-Old Mass Whale Die-Off

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Ancient blooms of toxic algae appear to have killed dozens of whales at once.
 

Sometime between six and nine million years ago, in a stretch of the Pacific Ocean just off of South America, something kept killing whales. Lots of them.

At least thirty baleen whales died, their bodies washed onto a tidal mudflat and buried over time. Species of sperm whale and a walrus-like whale, both now extinct, also died, along with seals, billfishes, bony fish and aquatic sloths. These die-offs, known as mass strandings, appeared to have happened over and over, with the animals buried in sediment between each episode.

Epochs passed. The skeletons, hidden underground, gradually fossilized. Geologic subduction pushed the sediment upward by about 130 feet, lifting the mud flats and transforming them into dry land in what's now known as Chile's Atacama Desert.

Then, in October 2011, during the final moments of a paleontological expedition in the fossil-rich region, Smithsonian researcher Nick Pyenson decided to look at the sediments being exposed by the widening of the Pan-American Highway from two lanes to four right near the coast. Stumbling upon evidence of the deaths, he and his colleagues were astounded by what they saw—dozens of complete, ancient whale fossils, along with those of several other species, including an extremely rare ancient dolphin species that had only been found a handful of times previously.

"At least ten different kinds of marine animals, recurring in four different layers," Pyenson says. "It begged for an explanation."

The problem: The road would be widened within two months, and the fossils had to be removed immediately.

This, of course, is a major no-no in paleontological research. Taking a fossil from its site erases its geological context, the main clue Pyenson and other researchers could use in figuring out what caused all these deaths in the first place.

The solution: lasers. Soon after the discovery, Pyenson returned to the site with Vince Rossi and Adam Metallo of the Smithsonian Digitization Program Office. Within a week's time, they used laser-powered digitization methods to create digital 3D renderings of the site, and its fossils, in extreme detail.

With these digital renderings, Pyenson and other researchers could inspect the fossils in their original context at their leisure, even after they'd been removed. Digital models of the whales could also be shared electronically with other scientists, and the researchers eventually made them publicly available (below: a baleen whale fossil), along with a datasets of their dimensions that allow anyone to print them at any scale.

Written By: Joseph Stromberg
continue to source article at smithsonianmag.com

4 COMMENTS

  1. Hmm, killed by toxins. How lucky we are to live in an age where alternative medicine has found a plethora of ways to purge toxins from our bodies. Sadly however for these whales the modern art of whale acupuncture, as practised mainly by the Japanese these days, had not been invented in time to help them.

    All of which aside this is a fascinating find. I wonder how many similar discoveries lie just below our feet waiting for us.

    • In reply to #1 by headswapboy:

      Hmm, killed by toxins. How lucky we are to live in an age where alternative medicine has found a plethora of ways to purge toxins from our bodies. Sadly however for these whales the modern art of whale acupuncture, as practised mainly by the Japanese these days, had not been invented in time to help…

      Huh? Alternative medicine? Acupuncture?

  2. I once heard a talk by a geologist who did field work in northern Africa. He said that the fossil whale skeletons there tend to have the same orientation relative to north, which was interesting. Their bodies washed up along the shoreline of the time, and came to rest parallel to the high tide line.

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