More than a century ago one of the longest-running experiments in the history of science was started at East Lansing, Michigan. Every 20 years, scientists check in on it. After an extra, pandemic-induced, delay the time was ripe again this week.
In April 1879 William Beal buried 20 bottles, each packed with sandy soil and more than 1,000 seeds from weeds common to the area at a secret location on what is now Michigan State University's campus. Before herbicides, Beal hoped knowing how long seeds can survive in soil would help farmers fight them. The bottles were placed with their openings facing downwards so the seeds couldn't sprout, but every 5 years Beale planned to dig up a bottle and move the seeds to fertile soil, revealing which posed a long-term threat.
Had the experiment operated on Beal's original plans it would have long outlived him, but still ended late last century. However, in 1920, with only a few species still making their presence felt, it was decided the 5-year cycle was obsolete. The remaining bottles have been dug up every 20 years since, leaving the fifth-last bottle due for recovery last year until fears the team would be locked out of the building in which they hoped to germinate the seeds led to a postponement.
The bottle had its delayed moment of glory Wednesday morning, April 21. The inheritors of the Beal legacy are anxious to avoid vandals or the merely curious finding the remaining four bottles, so the location is a closely guarded secret, with digs occurring at night, in the dark, with shovels and torches. The recovered seeds were then placed in potting mix and put under lights, while being sealed away from contamination.
Many of the species Beal included in the bottles stopped germinating within the experiment's first few years. A few have proven hardier, however, and in 2000 the Beal Botanical Garden's curator, Professor Frank Telewski, got almost half the 50 moth mullein seeds to sprout, along with a solitary Malva rotundifolia. Clearly, these so-called weeds have nothing on Judean Dates.
Telewski, now in his 60s, has hand-picked three younger faculty members to assist him with the dig, and carry on the secret knowledge of the remaining bottles' burial site. One described it as "A direct line to history." That can be more challenging than simply not forgetting – any university plans to build or dig in the wrong place must be headed off without being too exact about where disturbance can't happen. The team all feel the responsibility as custodians of a experiment that has become a matter of university pride. "With every interview I do I get more nervous about caring for these plants," Dr David Lowry told IFLScience.
NPR reports that even with a precious map and Telewski's memory, finding the spot in the dark proved harder than anticipated, and the team feared they would not be done by sunrise.
For completeness, most of the 50 representatives of each species have been replanted, but a few specimens of less successful lines have been given to molecular biologist Dr Margaret Fleming to investigate the state of the internal cellular machinery. Although the experiment will intially replicate previous years as closely as possible, the team plan to try a few new tricks on the seeds that fail at first. Eight of the 21 species did not germinate even after five years, and one of these is known as fireweed. Noting how many plants in Australia and South Africa need smoke to germinate, the team told IFLScience they plan to expose the tray of failures and see if the fireweed ignites.
The Beal experiment is sometimes described as the world's longest-running science experiment. However, the Guinness Book of Records gives that title to the Broadbalk Experiment, which has been studying the effects of fertilizers on winter wheat since1843, 36 years before Beal started.
On the 20-year cycle, Beal's bottles will run out in 2100, 221 years after the experiment started. Seven years ago, a study on long-term bacterial viability, possibly inspired by Beal's work, set out to more than double that, with ambitions to last 500 years.