At least 40 baleen whales and other species of marine mammals fossilized in a dry desert of Chile have been explained with a “toxic bloom” theory. Does it explain all the findings?
The discovery was a sensation when announced in 2011 (see 11/14/11): fossil whale skeletons inland from the coast of Chile, perfectly preserved in dense numbers. “There’s never been a find of this size, or of this diversity, anywhere in the world,” one spokesman said on a video clip posted by the BBC. (although for density and size, it needs to compete with other well-known sites like the La Brea tar pits). The Cerro Ballena (“whale hill”) website, sponsored by the Smithsonian, has a map showing the individual fossils and their locations, along with photographs, videos and other information.
Now that scientists have documented some 40 specimens and carted them off to labs, they have a theory to explain how they got where they are, published in the Royal Society Proceedings B (open access). About 6.5 to 9 million years ago, they believe, there was a series of toxic blooms of algae (probably dinoflagellates that cause the well-known “red tides” today). Whales and other large marine mammals ingesting infected fish probably died and were washed ashore. Moreover, since the whales were found at four levels, this probably happened multiple times over an estimated period of 16,000 years. New Scientist, Science Magazine, Live Science and the BBC News have echoed this explanation.
The theory needs to account for several unusual facts:
- The whales were mostly found in a belly up position, mostly in the same direction along a line parallel to the coast.
- Many of the whales were articulated and complete.
- Along with baleen whales, the fossil graveyard includes sharks, seals, dolphins (including “dolphins that evolved a walrus-like face”), and “bizarre aquatic sloths.”
- The fossils are encased in fine-grained sediment. There is orange soil in places that might be remnant of toxic algae, but the researchers are not sure.
- Some of the bones seem to have marks made by crabs. “Given the unique food resource provided by marine mammal carcasses, it is not surprising to find scavenging traces on individual balaenopterid bones that we attribute to crabs,” the authors say.
- Hundreds more fossils may exist in the graveyard. The researchers only had two weeks to excavate before a stretch of the Pan-American Highway was built over the site.
- The site today is on the edge of one of the driest deserts in the world: the Atacama Desert.
In order to explain why the carcasses would have been slowly buried by sand, the theory claims that there were no large land predators at the time. Still, they would have needed to be washed up high enough to escape the ravaging effects of marine predators (worms, bacteria, etc.) and seabirds. It would seem normal high tides would be incapable of getting the whale carcasses high enough above the surf; perhaps storm surges did it. Unless sand buried them quickly during the surge, though, it’s not clear how they would have been buried by sand in time to become fossilized. But then, how did crabs get to the bones? Why would this mechanism occur four times in a few thousand years (1/200 the assumed 3.5 million years of the deposit), and not more? None of the articles mentioned these or other problems with the theory. Instead, they presented the theory as a triumph of science. “This is an awesome snapshot of deep time,” a Stanford marine biologist said, even though he had just remarked that the findings “are revealing something that we didn’t know anything about.”
While we can all be amazed and delighted over this discovery, we must deplore the uncritical treatment by the media. They seem incapable of thinking logically or asking the tough questions that reporters ask of politicians. They just regurgitate the explanation scientists give, never thinking to themselves, “That doesn’t make sense.” They rarely go off and compare this site with other sites, like the Peru location that has 346 whale fossils buried in diatomaceous earth (2/02/04). Reporters just stumble about from story to story, copying the thinking of the shamans, doing little more than rewriting some of the boilerplate text in their own words.
The official explanation could be correct; nobody knows, because no humans were there. Several aspects don’t add up, as mentioned above. There doesn’t appear to be any reason to postulate four distinct episodes, just because they are found in layers. A single storm surge or flood can deposit multiple layers. If “hundreds” more whales exist in the deposit, it becomes less credible to imagine placid red tides killing that many large marine mammals and depositing them high above the highest tides, where they sat in the open air long enough for crabs to gnaw on their bones, but the bones never scattered till they were buried in sand. This happened at least 4 times?
Reporters toss around the “millions of years” like word salad. But millions of years doesn’t help. It makes the story less credible. Are we to believe that all these fossils were deposited in 16,000 years, just one half of one percent of the assumed age of the deposit? What happened the other 99.5% of the time? Were there no red tides for millions of years? No storm surges? There should be over 200 times as many whale graveyards in those strata if that much time elapsed and this was a routine occurrence.
Learn to ask questions the reporters never ask. Think logically, rather than taking their words on faith. Faith is supposed to be a no-no in science, isn’t it? Scientists and reporters treat faith the way Finagle treats miracles: “Don’t believe in faith; rely on it.”