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Freezing Life: Cryogenics Is The Last Hope For Many Endangered Species

Scientists in the US and Australia are freezing samples of coral in hopes that polyp organisms and sperm may allow them to regrow coral in the lab and replace dying species in the ocean.

The Great Barrier Reef is dying. As pollution and other man-made influences threaten the reef, which is not expected to survive past 2050, Australian scientists are taking measures to freeze the corals’ demise – literally. They hope to save the endangered species by freezing eggs and sperm from the coral, then fertilize and regrow the coral in the lab. As they enter the deep freeze, the Great Barrier Reef coral will become the latest in a large number of species stockpiled in cryogenic chambers in an attempt to reverse the advance towards extinction.

The first experiments in the 1950s attempted, with little success, to freeze sperm from the bull, ram, fowl and other mammals. Today there are a number of institutions around the world collecting all sorts of biological material from the animal and plant kingdoms as an insurance measure against endangerment or a world catastrophe of biblical proportions.

In 1972, the San Diego Zoo began freezing skin cells from rare and endangered species in hopes that future technologies could bring species back from the dead, if it came to that. This was long before the science of molecular biology advanced to a point where DNA would be sequenced, duplicated, and manipulated. Today, 8,600 animals of 800 different species are preserved at the zoo. Included among the samples are cells from the northern white rhino. There are only seven northern white rhinos left in the world, two females and five males. The survival of their species lies entirely in the zoo’s vials of liquid nitrogen that keep the cells, as the group has produced no offspring since 2000.

Other groups, like the Reef Recovery Institute, have their own efforts to cryopreserve coral.

The prudence of those 1970s scientists could pay off soon. This past August a group of scientists at Kyoto University in Japan successfully turned embryonic stem cells from mice into sperm. The sperm was then used to impregnate a dam, and led to the birth of a healthy litter. With all the biological alchemy that stem cell researchers are doing with skin cells these days, it’s easy to believe that the experiment’s success will eventually lead to the conversion of skin cells to gametes. Even though the study was done in mice and it remains to be seen if human skin cells can be similarly converted, it certainly was a promising outcome.

A number of other groups are putting the prospect of extinction on ice. The Smithsonian’s Genome Resource Bank, which is helping to preserve the coral, has a repository that already contains more than 1,600 samples of frozen sperm or embryos from 70 different species including endangered species such as the cheetah, black-footed ferret, and Eld’s deer. It also stores over 8,000 blood serum samples from 80 species. The UK’s Frozen Arc is home to 48,000 samples from 5,000 different species.

Plants are being put into a prophylactic deep freeze as well. The Svalbard Global Seed Vault in Norway has over 400,000 different samples totaling some 200 million seeds. Rather than preparing for a global catastrophe the Svalbard Vault serves more as a safety net to the 1,400 crop diversity collections around the world. Many of the collections are located in politically and economically unstable countries. The Svalbard Vault is meant to ensure their sustainability when samples are lost or destroyed.

As for saving the Great Barrier Reefs, gametes will be harvested from the colorful polyps that decorate reef surfaces. Polyps are the builders of coral. The soft-bodied organisms have a protective limestone skeleton at their base. After setting down to spend their lives on a particular rock or the sea floor, the polyps multiply into a cloned colony of thousands that behave as a single organism. Large stretches of fused calicle are what we call coral reefs.

By freezing polyp embryo and sperm cells and storing them in a cryo vault, scientists in Australia and the US hope to create a kind of Noah’s Arc for coral to ride out the angry climate change calamity. Increases in water temperature leads to coral bleaching, the whitening that occurs when algae living inside the coral are expelled. Bleached coral can survive, but mortality does rise due to increased stress. Optimistically, the cryofreezing scientists hope to replace the dead coral with healthy coral once the climate stabilizes.

The Great Barrier Reef, one of Australia’s great national treasures, is the world’s largest reef system. In fact, it is the world’s largest structure built by living organisms. The approximately 20,000 years old reef is comprised of over 2,900 individual reefs and 900 islands that stretch across an area of about 133,000 square miles (344,400 square kilometers). Comprising 60 percent of total coral reef coverage it is the world’s largest.

Elkhorn coral is one of many species of coral facing extinction.

One-quarter of all marine species make coral reefs their home. But reefs are not only important for the underwater ecosystem, coastal people depend on coral for the sea life their habits harbor and to protect them from hurricanes and tsunamis. The Pew Center on Global Climate change estimates that coral reefs generate about $30 billion of the annual global economy. The reefs also represent a rich bed of biopharmaceutical opportunity. Scientists are digging through these “medicine cabinets of the 21st century” in search of cures for cancer, arthritis, and other diseases. Scientists predict that 70 percent of the world’s coral reefs could be lost over the next 50 years. In just the past 30 years, the Caribbean has seen an astonishing 80 percent of their corals destroyed.

Whether it’s to safeguard endangered species, preserve crop diversity, or assist human reproduction by freezing gonads, cryopreservation is a technique that could be nearing its long sought after potential. But while it makes sense in principle to combat the destruction of the Great Barrier Reef by freezing polyp material, can it really make a difference in practice? The 133,000 square miles that the Great Barrier Reef is over 40 percent the area of the continental United States. You wanna play Johnny Appleseed across that stretch of land? How about under water?

I asked Steve Palumbi, a marine biologist at Stanford and author of several books about ocean preservation, if he thought we could actually replace enough of the lost coral to make a difference. He wrote, “I am not familiar with the specific proposal but…on one hand it doesn’t seem like much of a gamble unless there is a huge cost or lots of natural coral reproduction will be thwarted. On the other hand, Noah took females on the Arc too – where would the eggs come from?”

In the absence of stem cell reprogramming into gametes, nowhere. But repopulating an area with northern white rhinos is more feasible and carries more impact than resetting 133,000 square miles of dead coral. Regardless, whether or not the cryo-coral plan works out, cryopreservation is sure to rescue some species on the path to extinction, whether they be some misplaced rice strains or northern white rhinos.

Palumbi’s response to my concerns: “Sure, this particular proposal may have holes. But underlying it is the worry that coral reefs will disappear within the next century, and that suggests more strident actions than normal. If you walked out one day and saw the very last coral in Australia about to die – what would you be willing to do to save it?”

I don’t know and I hope I never find out.

[image credits: Elephant Journal, NOAA, WillGoTo, and Reef Recovery Institute]
image 1: Great Barrier Reef
image 2: elkhorn coral
image 3: Hegedorn
image 4: Coral


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