Written By Tim Bateman
Coral reefs are under constant threat from local and global stressors, making conservation efforts more critical than ever. Approximately 25% of marine biodiversity relies on coral reefs, and their annual value was estimated at 30 Billion USD. Despite their ecological and economic importance, reefs are in serious decline, with a 15% decrease in coral growth globally over the last 20 years. Roughly 30% of the Great Barrier Reef, the largest coral reef in the world, was lost to a single bleaching event (2015-2018). Additionally, we are projected to lose approximately 90% of reefs worldwide by 2100 if we continue “business as usual” CO2 emissions, according to the latest report from the Intergovernmental Panel on Climate Change. However, despite this bleak outlook, various conservation and restoration efforts are underway to preserve corals for future generations.
Conservation approaches such as marine protected areas (MPAs), selective breeding, genetic modification, and gamete cryopreservation have all been explored as possible methods for protecting coral reefs and ensuring their future survival. MPAs have been the first line of defense for sensitive marine habits such as coral reefs and effectively reduce local stressors such as overfishing. Unfortunately, MPAs cannot address global threats such as ocean warming, which is the primary cause of coral bleaching and mortality. Conservation nurseries that seek to grow healthy corals and replant them on reefs have employed “selective breeding” to propagate the most resilient genotypes on reefs and increase overall resilience to both local and global stressors. Cryopreservation of coral cells has been successful in some species but has not been extensively tested, where in some cases resulted in reduced fertilization success, and the technology is not widely available. Thus far, conservation and restoration efforts have found some success but not at a rate that can combat the perpetual decline of reefs due to climate change and other regional stressors. This calls for a new initiative to preserve corals.
The World Coral Conservatory (WCC) seeks to be this initiative by creating a “Noah’s Ark” for corals. The initiative is outlined in detail in a recent paper by Dr. Zoccola and colleagues (Zoccola et al., 2020). Briefly, the WCC seeks to build a biological repository for corals that uses the already established network of public aquaria and coral reef scientists. This method has been used successfully for other endangered populations and has the benefits of conserving corals, generating new corals without depleting wild stocks, and providing material for research on aquarium corals’ performance and interaction. In other words, the WCC will attempt to preserve as many coral species as possible in aquariums around the world. It will take advantage of the vast network of aquariums worldwide that already have the facilities in place to house corals while expanding research efforts. The WCC will also integrate with other efforts focused on reef restoration such as the 50 Reefs initiative and other groups to facilitate similar goals, such as identifying resilient populations and coordinating sampling efforts. If entirely successful, the WCC will use aquariums to facilitate further coral reef conservation, research, and education.
While the benefits of this method are evident, there are some challenges associated with aquarium conservation efforts. Some corals do not thrive well living in aquaria, requiring environmental conditions that cannot be replicated in an aquarium. Similarly, the ‘domestication’ of corals in aquariums raises concerns for coral genetic diversity, which could be critically reduced if sampling is not conducted carefully. The WCC has outlined a particular set of parameters for sampling efforts to combat this concern and prevent genetic diversity loss. How scientists distribute their sampling efforts is also a primary concern. Are there particular regions, species, or populations that warrant priority, and how should this priority be established? Current research efforts are focused on identifying resilient regions and refugia that can act as sources of resilient genetic material. Once identified, these resilient populations will be the focus of sampling efforts as they are the most likely to survive under future climate conditions. Additionally, further efforts are underway to identify resilient coral populations by methods such as the Coral Bleaching Automated Stress System (CBASS which aims to stress corals in-situ using a gradient of temperatures to test for resiliency to bleaching. Together, these efforts will maximize genetic variation and effectively focus sampling on the most promising populations.
Using the already established worldwide network of aquaria will facilitate the crucial link between conservation, research, and education necessary for coral survival. Not only will the WCC conserve corals but could also help inform policymakers resulting in reducing global emissions moving forward- a critical step to preventing the collapse of our oceans. As climate change is rapidly causing reef declines worldwide, the WCC initiative could be the “Noah’s Ark” coral reefs need to persist into the next century.
References and Further Reading
Allemand, D., and Osborn, D. (2019). Ocean acidification impacts on coral reefs: From sciences to solutions. Regional Studies in Marine Science 28, 8.
Ban, N. C., Adams, V. M., Almany, G. R., Ban, S., Cinner, J. E., McCook, L. J., Mills, M., Pressey, R. L. and White, A. (2011). Designing, implementing and managing marine protected areas: Emerging trends and opportunities for coral reef nations. Journal of Experimental Marine Biology and Ecology 408, 21-31.
Hagedorn, M., van Oppen, M. J. H., Carter, V., Henley, M., Abrego, D., Puill-Stephan, E., Negri, A., Heyward, A., MacFarlane, D. R. and Spindler, R. (2012). First frozen repository for the Great Barrier Reef coral created. Cryobiology 65, 157-158.
Parkinson, J. E., Bartels, E., Devlin-Durante, M. K., Lustic, C., Nedimyer, K., Schopmeyer, S., Lirman, D., LaJeunesse, T. C. and Baums, I. B. (2018). Extensive transcriptional variation poses a challenge to thermal stress biomarker development for endangered corals. Molecular Ecology 27, 1103-1119.
Zoccola, D., Ounais, N., Barthelemy, D., Calcagno, R., Gaill, F., Henard, S., Hoegh-Guldberg, O., Janse, M., Jaubert, J., Putnam, H. et al. (2020). The World Coral Conservatory: A Noah’s ark for corals to support survival of reef ecosystems. Plos Biology 18, 13.