Some bacteria have a remarkable capacity to survive being frozen or dried, something that could become a problem as the Arctic unfreezes. One of the most ambitious experiments ever designed, a plan to study this process over a period of 500 years, began in 2014. All the participants will be long dead before the experiment is even a quarter of the way through, but the first results have already been published.
If societies flourish when we plant trees under whose shade we'll never sit, the scientific equivalent may be to start experiments no one participating will get to complete. Some experiments date back more than 100 years. These are modest, however, compared to a project at the University of Edinburgh where 400 vials of dried Bacillus subtilis bacteria are intended to be kept and tested for half a millennium.
The bacteria were dried so they formed spores, whose protective outer layers keep out damaging chemicals and at least some radiation. When the time comes to revive, the spores have mechanisms to repair DNA that has been damaged, which the scientists want to study.
Not all the samples are to be left for five centuries untouched. Instead, every two years for the first 24 years some vials will be opened to see how they have been affected by their period in suspended animation. After this, the opening times will shift to every 25 years until the study is done. Even if some disaster prevents the experiment’s completion, plenty of valuable information will have been collected on the way.
The first opening of three vials took place in 2016, and the results have recently been published in PLOS ONE. These were compared with samples of the same bacteria stored under even more trying conditions for shorter periods. Storage at -80ºC (-112ºF) made no noticeable difference, and after more than a year in a near-total vacuum, 18 percent were still alive.
Among the bacteria woken early from their 500-year sleep, 86 percent survived their rest. Samples were tested for how long they survived exposure to X-Rays, ultraviolet light, hydrogen peroxide, and high temperatures.
Storage in dirt designed to resemble that on Mars did little to cramp the bacteria's style, but highly salty conditions proved more of a menace.
The experiment was inspired by the revival of bacteria found in century-old cans of meat and other astonishing feats of endurance. There are reports of bacterial spores found in salt crystals 250 million years old, and while these remain controversial others of astonishing ages are confirmed. As study leader Dr Ralf Möller of the German Aerospace Center acknowledged to The Atlantic, it takes optimism to believe our civilization will still be around in 500 years to keep the experiment going. However, he added, that applies to all exploration. “Our curiosity is always optimistic.”
One of the hardest parts of the project is to make sure future generations of scientists will know what to do. Once the process of attempting to revive desiccated bacteria with water only takes place ever 25 years, there may be no one from the previous round able to ensure exact replication of procedures.
Leaving instructions doesn't work if no one can read them – a project from 1994 would probably have instructions on floppy disk for example. Möller has stored USBs with the samples, but in case those don't last has also turned to older forms. Each generation of sample revivers has been requested to update the instructions to reflect any changes in language and technology, which by 2514 could be unimaginable for anyone living right now.