Scientists are rising the dead. Well, almost. Plants discovered in “ghost ponds” are being revived after lurking underground as dormant seeds for up to 150 years.
These so-called ghost ponds are formed when agricultural land expansion means that existing ponds are filled in, and literally buried alive, says Emily Alderton, at University College London (UCL), who led the study.
To expand a field, farmers commonly remove hedgerows then use the uprooted plants and soil to fill up any ponds. This happened at the site Alderton’s team studied in Norfolk, UK.
“Small ponds were not drained, but were filled in while they were still wet. We think this is likely to have contributed to the survival of the seeds buried within the historic pond sediments,” she says.
These buried ponds can often be seen as a ghostly mark on the landscape – a damp depression, change in soil colour, or patch of poor crop cover, where the ground never quite dries out, says Alderton.
“We also suspected that ghost was the right word as it hints at some form of life still hanging on and this is exactly what we have,” says co-author Carl Sayer, director of the UCL Pond Restoration Research Group. “The species that lived in the past pond are still alive, dormant and waiting!”
They have also had this happen in old castles and monasteries, doing archeological work and lifting stone pavers put down 500 years ago and getting seeds of herbs and weeds that sprout and grow... showing what was in the gardens there at the time.
The two oldest are the Methusaleh Fig, a collection of figs from pre 1000 AD found in a storage pot, an archeologist decided to put some in an incubator sprouter and got one to grow. The male fig tree is a kind that has not been seen since possibly 1000 AD and seems to be able to give pollen to cross with other figs. A push is on to run the rest through and see if they get any more to grow.
Another was a lotus seed found in a burial boat from Egyptian pharaoh times. Estimated to be over 2000 years old, a clutch of seeds were tended and one sprouted (circa early 1950's) and grew and two years later produced a pale pink lotus bloom.
It is amazing how long some seeds will lie dormant yet still grow.
Seeds are entirely fascinating to me. Most wildflower and tree seeds up here in the Sierras last 100+ years, just waiting for the next wildfire to give them some space to grow. Always makes me feel kinda stupid when I can't get some seeds to germinate, but these guys lying under pine duff for 100 years do just fine.
I listened to a CBC radio show last week, where they interview the guy from the world's largest seed bank, about all of the techniques used to keep seeds for thousands of years. They do tests on the various species, to see what is optimal and then they try to replicate those conditions in an unchanging environment. He listed some seeds that had lasted thirty thousand years in Siberian permafrost.