Too many scientific ‘discoveries’ get discredited

It’s not a good look for science when the most hyped, heavily marketed, and supposedly transformative discoveries are later discredited. Among the more spectacular cases were claims that a team of scientists had discovered fossilised Martian life in a meteorite, and that spores found in amber and salt crystals had been revived after lying dormant for millions of years. Last month, the research journal Science finally retracted a headline-grabbing study published in 2010, which claimed scientists had found arsenic-based life. NASA had promoted the discovery as bolstering the case for the existence of extraterrestrials and a new tree of earthly life known as the “shadow biosphere.”

The good news is that the wider scientific community didn’t buy the hype. Soon after all these bombshells dropped, skeptical scientists took a look at the research and discovered the flaws. These kinds of volunteer scientific sleuths play an important role in policing their fields. The real problem is the bureaucracy that’s grown around science — the peer-review process, the people who decide what gets published in elite journals, and those who market and promote the “discoveries.”

I encountered these allegedly textbook-changing claims as a science writer for The Philadelphia Inquirer, starting with the 1996 announcement of the Martian microbes that rode to Earth on a meteorite. NASA officials wanted to keep the findings a secret until a big press conference — a situation that makes it hard for reporters to do any truth-squadding in advance. And anyone who might have doubts tends to get drowned out by a torrent of early media coverage, which usually parrots the official announcement. In this case, reporters got a lucky break when the news leaked, and we were able to arm ourselves with information and points of view from independent sources before the big show. President Bill Clinton gave a speech about the historic moment, but the media coverage was not uniformly fawning. Most scientists with relevant expertise suspected the specimen had been contaminated with earthly life, which is the consensus today. Similar contamination was also the most likely explanation for the spectacular claim that spores had sprung back to life after slumbering inside a crystal for 250 million years, according to a study published in the journal Nature. There was no press conference that I knew of, so reporters had time to temper the excitement by talking to outside experts who had good reason to doubt this exciting find. By 2010, NASA and Science were more careful not to let the media get in the way of the story they wanted to sell. News outlets received a cryptic message about a big press event, where officials would unveil something of great significance related to astrobiology and extraterrestrials.

At the event, a team of scientists explained that they’d taken a type of bacteria that can tolerate arsenic, a toxic chemical. They said they had managed to make the bacteria incorporate some arsenic into their molecular machinery. This was supposed to show that life might not need to follow the same basic chemistry we know, and could perhaps exist in ways we haven’t seen. The evidence was very thin, but the presentation included music and slides of different life forms to hammer home the message that something profound was going on. The bacteria had come from arsenic-rich Mono Lake in California, but there was no apparent evidence that they had incorporated any arsenic in that environment. It was rooted in our normal tree of life.

There were some big holes in the story told to the media. How much arsenic was incorporated into the bacteria? How did researchers confirm this? Why didn’t the bacteria take up arsenic in the arsenic-rich environment of Mono Lake? What did this have to do with extraterrestrials? There was much innuendo and hand-waving for something that was supposed to change the textbooks. Purdue University biologist David Sanders said he heard the news on NPR. This was his area of expertise — he’d done work in the relevant area of biochemistry, so he was eager to look into it.

He told me he found a fatal mistake in the scientific paper. The researchers had assumed that the bacteria were eating and incorporating arsenic because they were starving them of phosphorus, and so they must have been taking up arsenic instead. But Sanders could see that their technique would have left enough phosphorus contamination for the bacteria to pick out what it needed and fend off the toxic arsenic — all well-documented behaviour. “It had nothing to do with the shadow biosphere. It had nothing to do with life on other planets, and it had nothing to do with reality,” he said.

University of Connecticut biologist Peter Setlow felt a similar skepticism as soon as he heard the announcement. It reminded him of those claims of fossilised Martian life and spores that were supposedly born before the age of dinosaurs. The expert in bacterial spores said he was interviewed on NPR, where he explained why those trapped in 250-million-year-old material probably latched on relatively recently.

It wasn’t enough to deflate the hype. While all these claims were eventually discredited, Setlow said many other spurious findings have been published in respected scientific journals. Sometimes peer review doesn’t work the way it’s supposed to. Reviewers raise objections, he said — as he’s done — and a journal will publish the findings anyway.