THE BIG FREEZE FOR CONSERVATION
Cryogenic freezing may conjure up images from sci-fi films or urban myths, but here at the zoo it’s a pioneering part of our conservation work behind the scenes in our state-of-the-art International Centre for Zoo Science.
We went into the lab with Conservation Scientist, Chloe Elliott, our resident specialist in Conservation Physiology & Reproduction, to discover more about cryotechnology and the 170 species that are currently part of the big freeze.
Can you explain a bit more about how animal cells are frozen and exactly what that process looks like?
Absolutely, I've had people think we have full size lions cryogenically frozen, so there are a lot of myths surrounding what cryogenic freezing is and why it’s important for conservation.
The tanks we use may hold thousands of animal samples, but they are actually only small, as each of the samples we hold is approximately 1cm x 1cm, so definitely no full-grown lions! The common theme is that all of the animal samples we keep in the tanks are facing huge challenges in the wild and the cell reserves allow us to support their future, if and when they’re needed.
When it comes to collecting samples, these are normally from animals that have sadly died. The samples collected are often small areas of the animal which hold an abundance of cells and the genetic material that we need to preserve that animal’s genes for decades to come. We currently hold animal tissue and cells starting from fire snails right up to Asiatic lions, and a host of species in between.
There’s lots of work to be done to develop the techniques for such a wide range of species, but by preserving these samples now, we can save important genetics that would otherwise be lost.
Just how low are the temperatures in the tanks?
Before any of the samples go into the tanks they go through an initial cleaning process and we use antibiotic treatments to prevent any contamination.
The samples undergo a controlled cooling process at around -80°C for 24-48 hours before being moved into cryogenic tanks at the extremely low temperature of around -196°C to prevent damage.
This process and level of cold makes sure that all the samples remain usable and healthy without damage from crystallisation. This is similar to when you freeze any kind of liquid and the water inside and around the cells or tissue turns to ice. This can be harmful and damaging because the water can form sharp ice crystals. If those crystal shards become big enough, they can poke holes within the cell and tissue membranes (similar to poking a hole into a balloon).
How do you choose animals that make it into the bank of samples?
It really takes a lot of planning and collaboration to choose the samples and ensure we have a diverse range of species that this sort of technology can hopefully help to protect from extinction. We’ve also been working alongside Toronto Zoo and Dublin Zoo to share knowledge and coordinate our efforts on the animals we are working to protect, using the best possible cryopreservation techniques. These collaborations are also an important part of our work with broader global initiatives, like the International Union for Conservation of Nature (IUCN) Animal Biobanking for Conservation Specialist Group.
There’s lots of work to be done to develop the techniques for such a wide range of species, but by preserving these samples now, we can save important genetics that would otherwise be lost.
What are some of the latest animals to be added for future conservation?
After the recent death of 18-year-old Asiatic lion, Iblis, here at the zoo we wanted to ensure his legacy and genes live on through our cryopreservation work. We were able to take some small samples from him which are now going to be kept for decades to come. As Iblis was such a loved and admired animal here at Chester, it’s so rewarding to see him play his part in the future of our conservation work.
What are some of the latest animals to be added for future conservation?
After the recent death of 18-year-old Asiatic lion, Iblis, here at the zoo we wanted to ensure his legacy and genes live on through our cryopreservation work. We were able to take some small samples from him which are now going to be kept for decades to come. As Iblis was such a loved and admired animal here at Chester, it’s so rewarding to see him play his part in the future of our conservation work.
What’s your personal favourite animal that is part of the project?
I have learnt so much about some of the lesser-known species since I began working in cryopreservation. The Javan green magpie is a particular favourite of mine – it’s so beautiful and eye catching, while sadly being on the brink of extinction in its native Javan habitat. It’s one of the most sought-after songbirds in the world, with as little as 50 of them potentially left in the wild.
They have incredible bright green feathers, with a bright red beak and legs, and their black "bandit's mask" around their eyes is unmistakable.
