By: Brayden Forster
Estimated Read Time 3 – 5 minutes
(WWF, 2022)
Introduction
Below the ocean surface resides a vibrant ecosystem known as coral reefs. Coral Reefs or the rainforest of the sea are critical ecosystems that help balance marine life and provide an array of benefits for humans. However, they have been experiencing a decline as a result of ocean acidification, an increase in natural disasters, and increases in ocean temperatures. The issue resides in the idea that coral reefs are providers of economic benefits like jobs, coastal protection, and even tourism for millions of people. A study conducted by Jay R.S. Doorga highlights the risk assessment of tropical islands from coral reef vulnerability.
How Are They Being Affected?
Climate change is a significant threat to the well-being of reefs largely through a combination of rising ocean temperatures and ocean acidification. Coral reefs require a delicate balance of water temperature and acidity and are extremely sensitive to changes in either. Climate change has stressed corals to a degree that causes a bleaching event where they expel the algae or zooxanthellae that live within their tissue. When coral is bleached, they are left susceptible to death and disease. Ocean acidification and rising ocean temperatures are inherently connected as when the ocean absorbs more carbon dioxide it both increases In temperature and acidity. This disables the coral to effectively rebuild their skeletons which makes them weak and vulnerable to deterioration.
Method
Figure 1: Map of Reef Vulnerabilities and Bleaching Severity (Doorga et al, 2023)
Research conducted by Jay R.S. Doorga in the Small Island Developing States (SIDS) involved using a combination of satellite data and weighted criteria such as sea surface temperature, temperature variation, and concentration of chlorophyll. When put together in a model it in turn reveals spatial vulnerabilities to reefs around the island and the bleaching severity as seen on the left in Figure 1. Within the model, temperature fluctuation was used as the most important factor that would influence coral vulnerability which is important in the light of climate change. The extinction and biodiversity rates were shown to greatly accelerate in areas of high or critical bleaching severity. This essentially means there could be cascading effects on the livelihood of the millions who reside there, especially when 94% of the population live within 100km and rely heavily upon their relationship with coral reefs.
How Can We Make a Difference?
Just because this issue isn’t something we visually see unfolding every day does not mean we are restricted to doing nothing. Climate change has the biggest fingerprint on coral decline so a big start would be slashing the amount of greenhouse gas emissions we emit as an increase in CO2 is the leading cause of rising ocean temperatures and ocean acidification. Moreover, either being actively involved or supporting various marine conservation groups can be a critical step in educating us in other ways to both restore and safeguard the rainforest of the sea.
Conclusion
In conclusion, coral reefs are more than just underwater ecosystems, they are protective lifelines for humans and marine life. The balance they all rely on is being disrupted by the likes of climate change causing ocean acidification and an increase in ocean temperatures. What’s important is that we must reduce greenhouse gases and engage in educating ourselves in ways we can preserve them in the future.
Resources
Doorga, J. R., Pasnin, O., Dindoyal, Y., & Diaz, C. (2023). Risk assessment of coral reef vulnerability to climate change and stressors in tropical islands: The case of Mauritius. Science of The Total Environment. https://doi.org/10.1016/j.scitotenv.2023.164648
WWF. (2022). Coral reefs and climate change. WWF. https://www.wwf.org.uk/coral-reefs-and-climate-change.
US Department of Commerce, N. O. and A. A. (2012). What is ocean acidification?. NOAA’s National Ocean Service. https://oceanservice.noaa.gov/facts/acidification.html#:~:text=Ocean%20acidification%20refers%20to%20a,CO2)%20from%20the%20atmosphere.
Hoegh-Guldberg, O., Pendleton, L., & Kaup, A. (2019). People and the changing nature of coral reefs. Regional Studies in Marine Science. https://doi.org/10.1016/j.rsma.2019.100699
Hoegh-Guldberg O, Coral Reefs Under Rapid Climate Change and OceanAcidification. Science (2007). DOI: 10.1126/science.1152509
Hoey, A. S., Howells, E., Johansen, J. L., Hobbs, J.-P. A., Messmer, V., McCowan, D. M., Wilson, S. K., & Pratchett, M. S. (2016). Recent advances in understanding the effects of climate change on coral reefs. MDPI.https://doi.org/10.3390/d8020012
environmental change @ western 