Coral reefs - what is happening to them?
Did you know that around 25% of all marine life depends on coral reefs at some point I their cycle? Although they take up less than 1% of the ocean, they are home to over one quarter of ocean species! Around 45% of those corals are now at risk of extinction as following a global assessment and announced at COP29. By 2050, there is an estimation that over 90% of all corals will die out. Undoubtedly, this would be a catastrophe. But why exactly are coral reefs dying out? Are there many conservation efforts? And what can you do to help?
What is affecting coral reefs?
Coral reefs are very delicate ecosystems. Primarily, they are vulnerable to climate change. Rising sea temperatures effectively put stress on the corals. This causes them to expel symbiotic algae, which turns the corals’ colour pale or even white. This effect is known as ‘bleaching’ and it cannot be reversed unless the corals reabsorb the algae (and the effects of environmental stress are mitigated). Global bleaching events occurred in 2016 and 2017, and caused significant death of the Great Barrier Reef in Australia. These bleaching events are often exacerbated by high levels of UV radiation, and if the stress persists, the bleached corals die.
In addition to this, corals can die from ocean acidification, pollution and runoff. Corals skeletons are built using calcium carbonate, but increased absorption of atmospheric CO2 acidifies the oceans. The lower PH of the water reduces the availability of carbonate ions, which makes it harder for corals to repair themselves. Weakened reefs are a lot more susceptible to erosion and bleaching. Agricultural runoff of nitrogen rich fertilisers can cause algae blooms in an effect known as eutrophication. An abundance of algae at the surface of the water blocks sunlight and consumes oxygen that corals need for respiration. In areas polluted by micro plastics, corals are more susceptible to disease, overfishing can remove key species that keep algae growth in check, more frequent storms physically damage reefs and there are links between high temperatures and outbreaks of deadly white syndrome diseases.
Many other factors exist, but the key similarity between all of them is that they are caused by human activity.
Other impacts of coral reef death
We have mentioned already the loss of biodiversity that comes with the death of corals, but this is by far not the only impact. Perhaps even closer to our lives are r the economic and cultural impacts of such a catastrophe. Coral reefs contribute to fish farming, tourism and coastal protection. Damage to reefs would cause the global economy billions of dollars annually. In fact, the global coral reef tourism industry generates 36 billion dollars annually. Activities such as snorkelling, diving and other reef excursions are major draws. The Great Barrier Reef alone supports over 64,000 jobs in tourism, and provides income for many more in the Queensland area. In addition, over one billion people globally in developing countries rely on reef associated fisheries for food and livelihoods. With 90% of coral reefs gone, coastal protection, food security, marine organisms used in pharmaceuticals and many jobs would be impacted. The cascading effects of such a disaster would impact food supply chains, raise prices, displace people and cause economic decline.
Rebuilding, conserving and what you can do!
Thankfully, not everything is so bleak for coral reefs! Programs such as the coral nurture program have planted over 68,000 coral fragments in the Barrier Reef. These pieces are grown in underwater nurseries and then transplanted into degrading reefs to boost them. Techniques to mass produce coral larvae are also scaling up. “Coral seeding” for example, involves releasing millions of larvae into damaged areas for natural regeneration. Building artificial reefs is another alternative to promote coral growth and attract marine life. These structures made of eco friendly materials mimic reef environments, which can help the corals grow back. Scientists are also investigating genetically engineering of corals to become heat tolerant and reduce environmental stress. These super corals could be cabals of withstanding warmer ocean temperatures.
In addition, there are also several global, regional and local initiatives. The UN coral reef initiative promotes sustainable reef management and provides funding for conservation projects worldwide. The Paris agreement aims to limit global warming and sea temperature rise to 1.5 degrees Celsius. The resilient reef initiative works with pacific island communities to build reef resilience through traditional methods and scientific expertise. The Great Barrier Reef foundation program focuses on improving water quality and combating populations of crown of thorns starfish, which eat the corals. There are also projects to scale up some of the smaller technologies and restoration efforts.
It’s actually quite simple for you to help! From limiting energy use in general and trying to consume sustainably, to promoting awareness and supporting the many conservation programmes. Donations are always welcome to any of the organisations listed above or simply international bodies such as the WWF. There are also options to volunteer for beach clean ups, or minoring programmes offered by conservation groups. Even the smallest things such as sharing this article if it proved educational can go a long way!