Today, coral reefs are facing more stressors than they ever have in modern history. An estimated 50% of reefs have been lost within the last 30 years, with annual die off continually increasing. If this trend continues, 90% of global coral reefs are predicted to die off by 2050. Stressors placed on corals include global warming induced coral bleaching, ocean acidification, harmful tourism, overfishing of keystone species, increased pollution entering the ocean, and detrimental coastal construction. It would be a falsehood to say that the future of coral reefs does not currently look bleak. Ocean acidification, which occurs when increased amounts of C02 in the atmosphere are absorbed directly into the ocean, perhaps poses the biggest threat to corals. This overabundance of CO2 absorbed into the ocean reduces the pH of the water and reduces the saturation states of calcium carbonate. Calcium carbonate acts as the main component in the structures of which corals are made, and therefore low saturation states limit and have the potential to cease coral growth. The calcium carbonate structures of the corals also act as the main structure of the reef because as corals grow and die new corals grow atop of the old. This cycle continues and over centuries reefs are formed. I annotated an article on hypothesis which details the immense stress that is currently being placed on coral reefs and possible solutions to this global crisis.
The Great Barrier Reef is the largest living structure on earth. Stretching 1,400 miles along the eastern coast of Australia, it can be seen from space. The Great Barrier Reef has an estimated net value of $56 billion, specifically providing 64,000 jobs to Australians and contributing $6.4 billion to the Australian economy (O’Mahony et al. 5). The Great Barrier Reef is also under immense stress. Bleaching has led to the die off of 67% of the northern Great Barrier Reef with the first mass bleaching event occuring in 1998. The reef bleached once again in 2002, and more recently in 2016 and 2017. The Great Barrier Reef could recover, with some of the fastest growing hard corals requiring 10 years to regrow some structure, but it would require 10 years free of significant stressors. Ocean acidification and the strong possibility of further bleaching events, as well as harmful tourism, pollutants, and overfishing all seem to negate the possibility of a stress free period.
Ocean acidification poses significant threats to the future of corals and the reef, but that is not to say that there is no hope for this crucial ecosystem. The absorption of C02 into the ocean and the resulting reactions, otherwise known as ocean acidification, directly correlates with the amount of CO2 present in the atmosphere. When there is less carbon dioxide in the atmosphere, there will be less absorbed into the ocean, and less stress will be placed on corals. As soon as humanity sees the immense value of coral reefs, and we decide to take action, immediate results will be visible. The reduction of carbon dioxide emissions will also mitigate global warming and assist in keeping the average temperature of the ocean from rising further. In turn, this will lead to less severe and less frequent global coral bleaching events. Furthermore, the elimination of stressors that are placed on corals at a local level will give corals the ability to focus all of their energy on combating and adapting to global stressors including ocean acidification and global bleaching events. Local stressors, which include harmful tourism, overfishing of keystone species, increased pollution entering the ocean, and detrimental coastal construction, must be eliminated, and it is not difficult to do so. Simply being an environmentally conscious tourist by never touching nor kicking a reef, by using eco friendly sunscreens, and by not littering while you visit a reef can significantly reduce stress placed on a reef. Coral reefs can be saved, but it requires global action as well as local conservation efforts.
Photo by CoralCoE