Climate Crisis and the Environment

Coral Reefs Are The Stars Of The Ocean Floor – Why Are They Losing Their Light?

coral reef
Ella Pilson

Coral reefs are not just the home of some of our favourite ocean creatures, from starfish and seahorses to turtles and sharks, with their mangrove forests and seagrass beds acting like nurseries for many of these species – as any Nemo lovers will know! But, these sites are also crucial in supporting one of the most diverse marine ecosystems on Earth (The Coral Triangle located in Southeast Asia being one such example). Worldwide, these marine environments are thought to be home to 25% of all marine species. 

They are also treasure-chests for humans, bringing in around £6 trillion each year on account of the tourism and fishing they provide. Furthermore, they act as a form of coastal defence, having the ability to  reduce the  effects of rough storms or tsunamis by decreasing the energy of the waves by 97%. They also show a lot of potential for the development of modern medicines, extracts taken being used in experimentation for cures in cancers and other bacterial and heart diseases. 

red algae spreading along the Caribbean waters, devouring the coral

How is climate change affecting these ecosystems?

One major threat to these species, quite literally draining the life of these corals, is ‘coral bleaching’. Coral bleaching refers to when, due to rising water temperatures, algae is released within the tissue of corals – turning their groovy orange, pink and yellow tones to white. These ‘mass bleaching’ events are becoming more and more common. 

This rise in water temperature has also caused an increase in dangerous forms of algae, and the establishment of worrying new types. Some evidence taken from 2016-2021 has revealed the development of 48 new peyssonneliloid species. One example is the red algae spreading along the Caribbean waters, devouring the coral and preventing regeneration of already damaged areas. The issue of algae damage exemplifies the fragility of this ecosystem, with marine species being so tightly interconnected and dependent on one another. 

A Case Study – The Great Barrier Reef, Australia:

I couldn’t write this without including something about this specific UNESCO world heritage site. Famous worldwide, the Great Barrier Reef has become the go-to image of vibrant corals and light-dark aerial shots. The reef stretches over 1,400 miles, off Australia’s north east coast, constituting 3000 different reefs and containing over 400 different types of coral and 1,500 species of fish.

global action is necessary to help reduce the greenhouse emissions responsible

Yet it is believed to have lost half of its coral since 1995, also becoming victim to coral bleaching, as well as other deadly threats – for example, an increase in predators like the crown of thorns starfish. These spiky, venomous and speedy starfish, being able to move up to 20mph and eat their way through 20 square miles of reefs per year, have posed a huge issue to the vitality of this reef.  And although creepy, being able to live 9 months without eating, they cannot be completely demonised – when regulated they are key to maintaining balance and diversity within the marine ecosystem. 

Rises in global temperatures here too has increased ocean acidification and reef erosion. Whilst pledges have been made and money been poured in, global action is necessary to help reduce the greenhouse emissions responsible for the warming, by moving away from fossil fuels. 

A bit closer to home: 

On the news it has become normal to hear about sewage and the gross abuse and irresponsibility by water companies, leaking toxins into rivers and the open ocean. This too is a major cause in the increasing threat of algae within our own natural waters, riverbeds and lakes, as well as impacting human health – people swimming in these waters receive rashes, fevers and even liver or kidney damage. In England and Wales untreated sewage has been discharged into the rivers and sea more than 3000 times between 2017-2021. In America too, this algal bloom has become a major environmental problem in all 50 states and 1,700 warnings were released in 2021 in the potential risk it posed. Furthermore, it is responsible for a huge loss of marine life. In 2022, over 60 Californian sea lions showed signs of domoic acid intoxication, leading them to have seizures, disorientation and loss of muscle control. Similarly, in 2014 Lake Erie, the world’s 11th largest freshwater lake, was under threat of ‘harmful algal bloom’, which caused Toledo, Ohio to issue a “do not drink” order. This impacted nearly 500,000 people for three days, with those affected not being able to brush their teeth or cook, and over 100 falling sick. 

The actions we take each have an impact, and are vital in ensuring future  generations can experience and visit these truly astonishing reefs for themselves

But it’s not all bad!

It’s worthwhile to note that a lot of good is being done to combat these issues. Shorter- term methods include the building up of ‘reef resiliency’, making sure to protect larger reefs which can cause resurgences elsewhere. Measures have also been taken to cut back on overfishing and to support marine protected areas in key conservation sites. 

But primarily, the reduction in greenhouse gases and global warming is necessary for any conservation efforts to be effective long-term. Individually, we can help by supporting organisations like ‘Coral Reef Alliance’ which seek to protect these magical underwater worlds. And you don’t have to be in these tropical waters to make a difference – as the sewage leakages and increase of algae in our own waters show, this is a threat which affects everyone. Individually, small changes such as eating more sustainable seafood, volunteering, keeping our coastlines clean or walking somewhere instead of driving, can all have an integral role in reducing greenhouse emissions and protecting these precious environments. The actions we take each have an impact, and are vital in ensuring future  generations can experience and visit these truly astonishing reefs for themselves. 

Ella Pilson

Featured image courtesy of Li Fei via Unsplash. Image license found here. No changes were made to this image.

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