The Great Barrier Reef and other reef systems around the world are threatened by multiple processes, particularly ocean acidification and warming as a result of climate change. Reefs are complex life support systems and their degradation has devastating impacts on marine and terrestrial animal populations, including humans. Conditions imposed by climate change and a strong El Nino triggered two waves of mass coral bleaching starting in late summer of 2016, leading to sharp declines in coral species and habitats. Events like these are precisely why we have been putting all our efforts into establishing and applying the science around coral cryopreservation, as a means of saving genetic diversity which could otherwise be lost forever. Our team of biologists working with the Australian Institute of Marine Science (AIMS) and the Great Barrier Reef Foundation have been to four spawning seasons focussing on the cryobanking of keystone coral reef species (i.e. those that are essential to reef structure and function). The CryoDiversity Bank at Taronga Western Plains Zoo stores and cares for a portion of frozen coral cells until they are needed to re-seed the reef. This living genebank is also providing cells for studies which advance our understanding of coral biology and adaption to oceanic changes.
In late 2016, our team of research biologists collected 643 billion sperm representing 60 individual coral colonies and 9 coral species, 4 of which are new to the bank, bringing our Great Barrier Reef species total to 12 – the largest bank of coral cells anywhere in the world. Science on the biology and preservation of reef-based algal communities has also progressed. Collaborators at AIMS maintain cultured stocks of several genetically distinct types (clades) of symbiotic algae necessary for coral survival. Dr Daly and Mr Henley trained collaborators in cryopreservation techniques using freshly collected algal symbionts. Pilot trials were then conducted with each cultured clade to determine their ability to survive the freeze-thaw process. One of the three clades tested tolerated freezing well, and when thawed, was able to proliferate in culture. This is an essential step toward ensuring that our banked coral samples can thrive in future reef restoration efforts.
Taronga: Dr Rebecca Hobbs
Smithsonian Institution: Dr Mary Hagedorn, Virginia Carter, Mike Henley (PhD student)
Australian Institute of Marine Science: Dr Madeleine Van Oppen
Monash University: Prof Doug MacFarlane
Bush Heritage Australia: Dr Rebecca Spindler