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The Frozen Zoo: Cryopreservation of an Ecosystem

Coral reefs are like underwater cities full of different plants and animals.  They are super diverse, colorful ecosystems and one of the most interesting life forms on our planet.  But overfishing, land-based pollution, particularly plastic in the water, and global warming are huge threats to coral reefs’ survival.  Without proper attention scientists think the reefs could completely disappear by 2050.  As avid scuba divers, Bob and I have visited many reefs around the world including, most recently, the Great Barrier Reef. We have also enjoyed diving and snorkeling in the waters of the Indonesian Archipelago, Bali, Truk (Micronesia), Bonaire, The Cayman Islands, Bahamas, Guam, Florida Keys and Belize, unique habitats for marine life very close to our hearts.

Some interesting facts about Coral reefs:

  • Coral reefs make up a fraction of the ocean – less than 1% – but they provide a home to 25% of all the world’s marine life.  Over 4,000 different species of fish rely on coral reefs.

  • A common misconception is that corals are plants or rocks but they are animals.  There are hard and soft varieties of coral which live together in large groups called colonies.

  • Coral reefs provide food for the fish which, in turn, provide food for humans.  It’s estimated that around 500 million people in the world consume fish found on coral reefs.

  • Clear and shallow water is where coral reefs thrive.  They generally grow best at depths shallower than 70 meters (200 feet) where sunlight can reach.  However, too much heat is harmful, which is where the effects of global warming come in. 

  • Corals and algae have a symbiotic relationship but if the ocean gets too warm, corals expel their algae which causes them to turn white - a process known as bleaching.  In a desperate attempt to survive increasing ocean temperatures, some corals have been shown to emit vibrant colors, a phenomenon which has led to increasing their ability to absorb light and combat the stress of warmer temperatures.  Observation shows these corals glowing underwater. 

  • Coral reefs play an important role in protecting coastal communities from storms and water surges.  They act as a buffer and can slow down water flow as well as prevent coastal erosion.  Reefs can clean the ocean waters.  Many corals and sponges feed on particles found in the ocean which, leaves the water incredibly clear. 

  • Coral reefs have recently been found to be a new reservoir for medicine discovery. 

  • Coral reefs have historically attracted tourism, estimated to be 70-80 million divers and snorkelers per year.  This tourism is hugely important to local economies; particularly in lesser-known destinations which rely on international tourism

  • It has been recorded that coral reefs began forming as far back as 240 million years ago! Established coral reefs today are between 5,000 - 10,000 years old, although some individual corals may only live a couple of years

  • Although more commonly associated with tropical waters, coral reefs have been found in temperatures as low as 4ºC (40ºF) and depths of 2,000 meters.  These deep-sea corals don’t rely on photosynthesis to survive like their warm-water counterparts; instead, they feed solely on food particles from the surrounding water.


Photo credit: Latitude's travel expert, Dennus Baum, a professional photographer, has led photo trips to exciting scuba diving locations.

Some coral reefs are stronger and can handle the changes better, but many of them are in trouble.  The coral reefs in the Red Sea and the Gulf of Mexico are some of the most threatened. 

In southeast Asia almost 95% of reefs are in danger due to overfishing and plastic pollution which stops sunlight from reaching the reefs.  In the Pacific Ocean the weather pattern of El Niño, which heats up the water in the Pacific Ocean has caused bleaching events worldwide.  During the period 2014-2017, more than 70% of the world’s coral reefs were harmed.  El Niño happens every few years, causing more damage before the reefs can fully recover.

In Maui, reefs lost about 25% of their coral from 1994 to 2006.  In Honolua Bay, the coral cover went down from 42% to 9%, which is blamed mostly on sunscreens with chemicals that harm coral, like oxybenzone and octinoxate. 

Despite reefs being the main attraction for tourism in the Caribbean, the health of its reef systems has increasingly declined.  A study conducted by the World Resources Institute has found that “nearly two-thirds of reefs in the Caribbean are threatened by human activities while an estimated one-third is threatened by coastal development” such as construction and sewage discharge. 


In short, over 50% of the world’s coral reefs have died in the last 30 years.  A 70-90 per cent decrease in live coral on reefs by 2050 may occur without drastic action to limit global warming to 1.5°C.  Even with urgent reductions to greenhouse gas emissions, global ocean temperatures could still take decades to stabilize.

With all this negative news, there is also a great deal of hope and some innovative solutions in place to save the reefs.

The Great Barrier Reef in Australia is another massive reef system threatened by these factors.  The Reefs complex life support systems’ degradation has had devastating impacts on marine life and on terrestrial animal populations.  The Taronga Zoo in Sydney is the leading organization in Australia applying cryopreservation technologies to reef management, restoration, and research, for conservation management of the Great Barrier Reef.  Their team of biologists has been working with the Smithsonian Institute, the Australian Institute of Marine Science (AIMS) and the Great Barrier Reef Foundation have since 2011, focusing on the cryobanking of keystone coral reef species (i.e.  those that are essential to reef structure and function).

Coral cryopreservation, as a means of saving genetic diversity which could otherwise be lost forever.  The Zoo stores and cares for frozen coral cells until they are needed to re-seed the reef.  The total number of species now housed in Taronga’s CryoDiversity Bank is 30 and represents the largest coral bank in the world.  This living bank is also providing cells for studies which advance scientists’ understanding of coral biology and adaptation to climate change and other environmental changes.

Another Australian entity, the airline Qantas,  just announced a decade-long partnership with the Great Barrier Reef Foundation to invest $10m in a Reef Restoration Fund to Assist in revitalizing Australia's beloved natural treasures.  This partnership is part of Qantas's Nature Action Plan, which includes the company's commitment to achieving net zero emissions by 2050 and reducing carbon emissions by 25% by 2030.

These conservation efforts and scientific advances are aimed at saving the world food supply, protecting coastal communities, providing cleaner oceans, opening the door for new medicinal discoveries, and providing economic support through sustainable tourism.…. Good on ya, mates!


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