The scientists racing against time
Ice cores, seeds, and plants all contain vital clues that will be lost without nature archivists whose work is harder than ever. Scientists are working to preserve crucial records of the past, such as those from the Grand Combin glacier in the Alps, which has been completely destroyed due to warming conditions. They plan to excavate a trench near the Concordia research station in Antarctica to leave cores from up to 20 of the world's surviving glaciers, as many as they can reach before they melt. The scientists hope to leave these cores in a hole in the ground, where they would leave valuable information about the past. The Millennium Seed Bank at Kew Gardens houses living seeds of more than 40,000 wild plant species, stored in storage in a cold storage facility above the Arctic Circle. Joelle Breidy, a scientist who spent a decade hunting down the seeds of wild plants in Lebanon for the Millennium Seed bank, founded a national seed bank at the Lebanese Agricultural Research Institute in 2013.
ที่ตีพิมพ์ : 2 เดือนที่แล้ว โดย Veronique Greenwood ใน Science
For most of her career, Schwikowski has studied what is known as eternal ice, ice that has not melted for millennia. The air from long-ago versions of Earth is captured in bubbles in this ice, each one a tiny time capsule about the atmospheric composition and climate of the past. Across much of the planet, however, the eternal ice is no more. Just last year, when Schwikowski and her team were drilling on the Grand Combin glacier, 13,000 feet up in the Alps, they struck a layer of frozen meltwater. Since their previous drilling trip, warming conditions had caused the glacier’s upper levels to melt and drain through the lower levels, wiping out its record. Schwikowski, along with other scientists who are part of the Ice Memory Foundation , had been planning to put the Grand Combin core with others in the Antarctic ice cave. There it would have lain, untouched, until some future generation of scientists needed to ask questions about the former world.
If all goes well, decades from now, some of Margit Schwikowski’s most recent work will be in a hole in the ground. Schwikowski, a chemist at the Paul Scherrer Institute in Switzerland, and her colleagues hope to soon excavate a trench in the snow near the Concordia research station in Antarctica. They will inflate an enormous balloon within the trench, spread snow across the top, and wait for it to solidify. Then, they will remove the balloon and, in the hole that’s left behind, they will leave a precious record: cores from up to 20 of the world’s surviving glaciers, as many as they can reach before they melt.
In the grand sweep of history, records that survive have been the exception rather than the rule. Most of the time, what happens is lost. Sand buries settlements, oceans flood the land, fire consumes libraries — their information about what the world was once like draining away like a receding tide. But now, in an age of cataclysmic change, scientists are reaching out to the natural world and taking snapshots, in hopes that in the future, whether it’s next year or in hundreds of years, someone will be waiting and interested. The message in the bottle reads, “Here. Take this. This is what it was like.”
In the still air of a big concrete room under a hill in Sussex, England, there’s a quiet hum. Fans for a refrigeration system have kicked on to cool six chambers opening off the big room. Open a door, and row upon row of glass jars gleam in the dim fluorescent light. Most contain thousands of seeds, some as small as a grain of sand, some shaped like feathers, some like hairs. “It’s like a crazy pantry in there,” says Elinor Breman, senior research leader at the Millennium Seed Bank at Kew Gardens. Living seeds of more than 40,000 wild plant species are held in stasis here.
Each seed was collected by someone who waded out into the grasslands, paddled a boat into the jungle, knelt among the miniature plants of the Arctic Circle, or otherwise journeyed to where they hoped plants might still survive. Many wild plants are on the way out, with Kew estimating in 2020 that around 40 percent of species are threatened with extinction. To Joelle Breidy, a scientist who spent a decade hunting down the seeds of wild plants of Lebanon for the Millennium Seed Bank, the need felt so pressing that in 2013 she founded a national seed bank at the Lebanese Agricultural Research Institute. “From 2014 to 2018, my team and I were constantly on the move throughout the country,” she says, on collecting trips funded by the Crop Trust’s Crop Wild Relatives Project. They plucked the seeds of wild relatives of many crops, including wheat and barley, which are native to the Fertile Crescent, placed some in their own cold storage, and sent some here to England. (Seed banks can also send emergency backups of their collections to the Svalbard Global Seed Vault, built above the Arctic Circle by the Norwegian government as a storehouse of the world’s seeds.)
Above ground, where the chilly March light filters into the Millennium Seed Bank facility, recently arrived seeds lie in brown paper envelopes, each paper-clipped to a description. Leucas tettensis, reads one slip, revealing that it contains the seeds of a pert Zambian herb, with creamy flowers and dark leaves. In a nearby room, a technician is shaking something through a sieve — she is filling a little sack with ochre-colored seeds of an alder tree. Breman explains that each sample is cleaned, X-rayed to see if the plant embryo within is intact, and then dried and frozen, a process that greatly extends the lifetime of the seed. “You’re looking at tens to hundreds of years of storage,” she says.
Not all plants can be saved this way — oak trees, notably, will not grow from a dried, frozen acorn. Scientists can super-cool tiny fragments of a plant, like a dormant bud, in tanks of liquid nitrogen. With careful thawing and the right coaxing, these materials can be used to create a new plant. But it’s a delicate business, requiring specialized handling and many steps. A dry, cold seed is a simpler way of bearing a plant species into the future. For as many plants as possible, a scientist will make an entry in the bank’s herbarium — a single card, with a dried, pressed plant stuck to it, with its name, where and when it was collected, and by whom.
Already, though, time grows short. Shakeel A. Jatoi, curator of Pakistan’s gene bank at the Bio-resources Conservation Institute in Islamabad, has led more than 30 expeditions into remote corners of his nation. Sometimes, when he arrives where there was once a stand of rare plants, there is nothing there, just fresh pavement. “All lost, because of roads,” he says. In places where locals depend on the target plant for grazing their animals, it has proven impossible to collect mature seeds. By the time scientists are on the scene, the seeds have been swallowed whole. Breman herself leads expeditions to collect the wild plants of the Arctic, where warming is moving more swiftly than anticipated, and even in the best of conditions, on any collecting expedition, it’s hard to be sure that seeds will be ready and waiting when they arrive. In a film clip on the Kew site, she reflects, just before a trip, “Am I going to have a whole team of people out here and nothing to collect?”
As we emerge from the low bunker in Sussex, Breman tells me about the people who designed the building, a generation of scientists who got the money and set the plans in motion more than two decades ago. “The reason they built such a big space is that the structure should last 500 years,” she says.
I blink into the bright sunlight. It seems impossible that anyone could plan that far ahead. But then, that’s the problem, isn’t it?
In a pair of rooms at Duke University, there are more than 825,000 plants, each one dried, pressed, and labeled. It’s one of the largest herbariums in the United States, with specimens accumulated by botanists over the course of a century, all kept in steel cabinets in a space no larger than two basketball courts. The leaves of some plants show bite marks of insects that preyed on them before they were collected, a record of what lived alongside them. The collection’s samples are used by researchers around the globe. This past winter, Kathleen Pryer, a professor of biology who is the collection’s director, was told the university would like her to get rid of it.
Pryer was stunned. “Duke University in 2024 is celebrating its centennial. There are flags all over the place, there are all kinds of celebrations. And yet at the same time, a hundred years ago is when the Duke herbarium was established,” she told me on the phone recently. “It’s really unreal that they are celebrating a centennial by throwing out their 100-year-old herbarium.” The university, which has an endowment of $11.6 billion, cited costs as the reason. All the collection needs, really, is air conditioning, the salaries of a pair of collection managers, and oversight from a faculty member, Pryer argues. “They’re not fessing up to the fact that others want that space for something else,” she says.
But the herbarium has little protection against such shocks. It does not have its own endowment, a special pot of money the university is obligated to use for its maintenance. It was founded originally as part of a department of botany, which later merged with a department of zoology in 2000. It is now administered through a department of biology, whose leaders may or may not, at any given moment, be sympathetic to its existence. The collection received money from Chicita Culberson, a retired Duke lichenologist, until her death last year. Pryer had a video call with a prospective donor, a wealthy alumnus who wanted to provide $1 million for an endowment, with Duke coming up with $2 million more.
Her excitement that she’d found a way to ensure the collection’s future was short-lived. The week after that video meeting, the university “said they were closing us down,” she says. “They couldn’t let us keep going, when they want it to be gone.”
The news has sent shockwaves through the community of plant biologists. There is no collection large enough to absorb the Duke Herbarium, so if the university does not reverse the decision, the archive will be fragmented. And that is a frightening prospect, Pryer says. She was speaking with Barbara Thiers, the former head of the herbarium at the New York Botanical Garden, who started a list of herbaria around the world called the Index Herbariorum, about such transitions.
“She has told me that often what happens is things just get lost. There it was, sitting there ready to be used for biodiversity studies by anyone,” Pryer says. “And it just disappears.” In a dumpster, in a moldy back room, specimens are detached from their labels, detached from human knowledge.
At the University of Arizona, a remarkable collection lived for many years under the bleachers of the football stadium: millions of samples of tree rings that record the recent climate history of the Earth. “It was quite a mess. I was worried about termites,” says Malcolm Hughes, the retired director of the Laboratory of Tree-Ring Research, who arrived in 1986. Each ring in a tree can reveal whether the year it grew was a wet one or a dry one, whether it was hot or cold, whether there was a volcanic eruption nearby, what the atmosphere was like. The collection, in fact, was the linchpin of the modern system of radiocarbon dating: We know how old something from an archaeological dig is today because decades ago, scientists aligned the University of Arizona’s tree ring record with historical time.
The tree ring collection now has its own building, Hughes is relieved to report. In 2007, Agnese Haury, a social justice activist and philanthropist, came to their rescue. “That really saved the collection. We moved into the new building just over 10 years ago,” Hughes says. The collection is still yielding insights into the past — right now scientists are investigating how the individual cells within each ring can tell the climate and events of even smaller increments of time — months or weeks, not years. And it is still growing, with new samples added all the time.
The fate of the Duke Herbarium is upsetting, unsettling. “It’s obscene,” Hughes says. But without a long view — without money, lawyers, an institutional structure that outlasts any human life — an archive, even one as meticulously assembled and shelf-stable as the largest herbarium in the United States, can always evaporate.
Margit Schwikowski and her colleagues have got seven ice cores so far: two from Russia and one each from France, Switzerland, Italy, Svalbard, and Bolivia. They have tried to get permission to drill on Mount Kilimanjaro but have failed “for political reasons,” Schwikowski says. “This is sad, because the ice on Kilimanjaro is really finishing,” she says. “In 10 years it will not be useful at all.” She and the others are planning next to go to North America, to the Eclipse Icefield in the Yukon Territory of Canada.
In the cave the ice cores will need no refrigeration. There will be little need for maintenance. And there are many things that you can do now with an ice core that were not possible when she began her career — in particular, scientists have begun to analyze DNA kept frozen in glacier ice, providing a look into what was alive long ago. She hopes that in 20, 30, a hundred years, there will be new techniques, new questions, new answers.
Veronique Greenwood is a science writer who contributes frequently to Ideas.