Inside the Frozen Zoo, where by scientists put disappearing species on ice: ‘It’s banking hope’ | Conservation

In a basement laboratory abutting an 1,800-acre wildlife park in San Diego, California, Marlys Houck looks up to see a uniformed guy keeping a blue insulated lunch bag stuffed with tiny pieces of eyes, trachea, feet and feathers.

“Ah,” she suggests, softly. “Here are today’s samples.”

The bag in problem contains compact bits of comfortable tissue gathered from animals who have died of pure brings about at the zoo. Currently, the samples include things like a leaf frog and a starling.

The gentleman keeping the bag is James Boggeln, a volunteer with the zoo, who fingers it off to Houck, the curator of this laboratory, regarded as the “Frozen Zoo”. She and her workforce will start out the system of turning these bits of tissue into a lender of research and conservation for the long run. They will place the tissue into flasks exactly where enzymes digest them, then the lab customers will gradually incubate them around the course of a month – escalating an abundance of cells that can be frozen and finally reanimated for potential use.

At practically 50 many years old, the Frozen Zoo retains the world’s oldest, greatest and most various repository of residing mobile cultures – far more than 11,000 samples that depict 1,300 distinctive species and subspecies, together with a few extinct species and far more that are extremely close to extinction.

James Boggeln provides samples to the Frozen Zoo.

Currently the Frozen Zoo is operated by an all-feminine team of four, who check out over a large assortment of hand-marked vials with labels this sort of as “giraffe”, “rhino” and “armadillo”, all saved in enormous circular tanks loaded with liquid nitrogen. In a environment suffering from a local weather and biodiversity crisis, putting species on ice offers one way to be hopeful about the potential.

The perform carried out in this article has constantly felt significant, but an accelerating extinction crisis has place mounting tension on Houck and her group. It is a race from time to place samples into the Frozen Zoo right before they slip away from the earth outdoors the lab. The women who hold these work see it as their duty to keep the long run in spot.

The work can be painstaking – samples from birds, mammals, amphibians and fish all need various processes, for case in point. But with stakes so substantial, Houck describes it with a sort of sacred reverence.

She feels the tension of the role – when her predecessor was in demand, a mechanical failure led to the decline of 300 samples, a year’s operate. So her head is concentrated on keeping the samples the zoo has frozen protected, Houck claims – “but then mixed with the exhilaration and this pleasure, since it’s an honor to be able to do this”.

‘Collect factors for explanations you never nevertheless understand’

The zoo was launched by a German American pathologist named Kurt Benirschke in 1972, who started out a selection of animal pores and skin samples in his lab at the University of California at San Diego and then moved it to the San Diego Zoo a number of many years later. At the time there was no technological innovation to use it outside of simple chromosome exploration, but Benirschke normally quoted the American historian Daniel Boorstin: “You ought to gather issues for factors you really don’t nevertheless have an understanding of.”

Katy Thomson, investigate affiliate, feeds the cells ‘media’.

That quote continue to hangs on a poster in the Frozen Zoo, the place Houck pulls vials from tanks of liquid nitrogen that resemble large silver thermoses the size of a human. The tanks are pressurized at -320F, a temperature that stops cells from relocating or switching – holding them alive but in suspended animation. From this temperature, the cells can be revived and continue on dwelling as if many years – or centuries – hadn’t passed.

No species is exactly the identical, and some groups are much more demanding to preserve than other people. The Frozen Zoo started off with mammals, then expanded to cryobanking birds, reptiles, and amphibians. The good results price with mammals is shut to 99%, Houck claims. “With amphibians, it was close to 1% for a number of years, and now I consider maybe we’re 20 to 25%. Birds are fairly substantial.”

Racks in the nitrogen tanks maintain 100 vials each individual, and every vial consists of 1m to 3m residing cells. Those people cells – a giraffe, a lemur, or some thing additional endangered like a vaquita – hold attainable alternatives for an array of current and long run troubles.

Ultimately, the cells could be used to convey back again thoroughly extinct species – but that’s not the primary goal. Instead, the content is frequently utilized to rescue current species that are battling. In 2020, the Frozen Zoo used cryopreserved DNA to clone a black-footed ferret, the to start with endangered species in the United States to be cloned. Last yr, frozen cells cryopreserved 42 yrs in the past were being applied to clone two critically endangered Przewalski’s wild horses, bringing beneficial genetic diversity back again to the dwelling populace that will make it much more resilient to new ailments or environmental threats. Just one of the foals was named Kurt, after the Zoo’s founder.

Marlys Houck, the lab’s curator, and Misuraca get rid of samples from the tanks at the Frozen Zoo. Photograph: Maggie Shannon/The Guardian

The get the job done that San Diego’s Frozen Zoo is section of a world wide motion to cryobank everything from animals to seeds. Currently there are all over a dozen wildlife-based cryobanks about the world, primarily situated in North The usa and Europe.

The get the job done accomplished in San Diego has been particularly groundbreaking, suggests Sue Walker, head of science at Chester Zoo, and co-founder and vice-chair of the British isles nonprofit Nature’s Safe, a cryobank that collects dwell cells and sperm and eggs. She suggests that in a several more a long time, it could be possible to switch these cells into pluripotent stem cells, which can be reprogrammed to develop sperm and eggs.

In an perfect globe, species could be conserved in the wild – but in actuality, that is not the circumstance. “We’re losing species way too quickly for science to keep up,” she suggests. “So the the very least we can do is attempt and lender that product down.”

It is tricky to get permits to bring in tissues from animals in other international locations, so the hope is to increase the potential in other locations to cryobank locally, specially near conservation hubs in Africa, South The us and south-east Asia. But that suggests building up the capability to approach and maintain the inhabitants of cells in a uniform way. It’s high-priced and sophisticated perform – but also needed, Walker states.

Houck maintains a collection of rhinos in her business office at the Frozen Zoo.

“I assume we have to throw almost everything at it in purchase to conserve some of these species that are on the brink of extinction,” she claims. “It’s about banking hope.”

Time devices to earlier and potential

Doing work on the cell cultures can be like operating a time equipment. Houck was when researching rhino chromosomes and she opened a vial with her predecessor Arlene Kumamoto’s handwriting on it. Kumamoto experienced put the cells into a deep freeze the similar thirty day period Houck graduated from significant university. “I just thought, oh my gosh … she was freezing cells that I’m now using for my experiments. If she hadn’t performed that, I wouldn’t be performing what I’m carrying out,” Houck suggests. “What are we executing currently that will be applied in the potential?”

Julie Fronczek, who has labored at the zoo for 24 several years, appears to be like up from her microscope to present a theory about why a team of females is top this do the job at the Frozen Zoo. “We’re nurturing the cells. They are living creatures and they have to be fed and taken care of, then you have to know what they want when they want it,” she states. “It’s form of like toddlers.”

The group adds close to 250 to 350 specimens to the zoo every single yr. The leaf frog that arrived these days is a high precedence, Houck suggests. The starling that also arrived? Fewer important. These kinds of decisions weigh closely on her. Considering that just about every new animal that arrives wants to be cultured and preserved, and will take up place in the big containers, she has to contemplate how lots of of that species are by now represented, and how quite a few options there are to get far more of them. “I would like to not have to turn anything away. It would be much better if we could accept each and every sample that arrived in because they’re all essential.”

Julie Fronczek, senior investigation affiliate, pictures chromosome spreads at the Frozen Zoo.

The selection incorporates 3 extinct species: the po’ouli or Hawaiian honeycreeper, Rabbs’ tree frog, and the Saudi gazelle. They’re keeping a collective breath as they watch for a lot more species in their collection to go extinct. “The subsequent will in all probability be the white rhino and the vaquita,” Houck claims.

The space keeping the tanks is comprehensive – but the tanks aren’t yet at ability, so the staff carries on its work of culturing and preserving the cells that could signify life or loss of life for endangered animals in the foreseeable future.

In the foreseeable future, the lab desires to update its strategies – all those handwritten vials will ultimately be scannable barcodes. It also desires fresh scientists to come and keep a aware observe in excess of the expanding zoo on ice.

“I think we’re all pretty protective of the frozen zoo and the legacy and Dr Benirschke’s legacy,” Houck claims. “And I hope that we can instill a generation who will have it forward from us.”