The Secret Life of Corals – Part Two

After the last blog you might think you have a pretty good understanding of what makes these underwater jungles tick, yet the threats they face often fail to claim headlines as successfully as our terrestrial forests. The impact of cattle ranching and soy plantations in the Amazon basin is a relatively well-known story of human induced ecological damage, but did you know our reefs are declining twice as fast as our rainforests? We have currently lost up to one fifth of all coral reefs with their decline only accelerating as their location in nearshore waters leaves them exposed to our maritime exploits.

Climate change is one of the greatest pressures facing these beautiful ecosystems as coral bleaching occurs when water temperature remains 1°C above the seasonal maximum for several weeks. Once corals become stressed by temperature or disease, their happy relationship with the algae zooxanthellae goes out of the window as they suddenly turn into annoying clingy partners which need to be expelled as soon as possible, something which may ring a bell in a few human relationships! Once the coral has evicted these algal squatters, they lose essential nutrients and their colour, leaving the seabed bleached white. For climate change though, this is not enough. Increasingly acidic seas will start to dissolve coral skeletons within the next three decades, leaving the branches thinner than ever and susceptible to being broken apart by strong waves. Global warming, set on destroying our ocean wonder, is even progressively generating these more ferocious tropical storms which will break apart delicate coral colonies.

Under our growing consumerism and novelty product obsession, plastic is yet another major threat to these fish nurseries as shopping bags entangled with coral block the sunlight needed for growth and can even snap branches all together. Even simply touching our synthetic creations can increase the risk of disease twentyfold, leaving a weak spot for bacteria to invade. Once our bags have broken down into fragments, microplastics are easily confused for dinner chunks with corals now actually preferring the cocktail of chemicals our waste provides over natural fodder. Some corals have been found to eject the plastics after 48 hours but not before any chemicals or diseases carried on the plastic have invaded their tissues. Every minute one garbage truck full of plastic is entering our oceans, with an estimated 1.1 billion items tangled around our favourite diving spots, so unless we curb our often unnecessary use of plastics, our dreams of gliding amongst turtles will vanish as quickly as a frightened fish.

The perils don’t stop there either, with dynamite induced coral mining often used in countries like the Maldives where limestone derived from coral is the cheapest building material; yet for every $10 this short-minded activity makes, the local community loses $254 from destruction of this food and tourism base. Mined coral also provides us with local jewellery, a cement substitute and lime which is used to alter the acidity levels in agricultural soil. Unsustainable fishing methods, such as trawling, break apart reefs whilst emptying the area of caretaker-like fish which nibble away intruding seaweed from the surface of coral. Even rainfall contributes, washing fertilisers off agricultural land, bringing with it disease, toxic chemicals and excess nutrients which send bacteria numbers off the charts.

As our laws and technology cannot directly control the contents and temperature of the ocean and as our behaviour over the last century has already committed us to significant long-lasting damage to these slow growing species, you must be wondering, is there any hope? Australia alone has committed $300 million to reef research with their laboratories now taking advantage of the great spawning event, even if they only have chance to work for a few hours a year. By collecting a variety of coral species ready for this reproduction event, they hope to harvest a variety of gametes which they can then cross breed to create a hybrid coral more resistant to warmer temperatures and disease. While they wait as eagerly for this annual event as we do our birthdays, they pass the year by raising corals in heated and bacteria filled conditions, hoping that quick adaption and evolution will once again save our planet’s life from extinction. In fact, some species are already thriving in heatwave conditions with the fantastically named smooth cauliflower coral in the Red Sea living in 30°C heat. Yet re-planting this coral on a global scale is simply not a viable option, leaving 3D corals as our next best hope. These artificial ceramic corals are now deployed in the Maldives and new technology has allowed them to be intricately designed to masquerade as real coral, with our previous steel structures failing to camouflage quite so well. This hopes that coral larvae will more freely attach to what they believe to be a real reef to kick start colonisation which will then create the essential base of the food chain in ocean patches over the world. Even if this results in disappointment, these structures could replace reefs as a more natural, unseen method of flood protection for island communities who rely heavily on natural defences from reefs to mangroves. Without even really focussing on corals, our sustainable futures may benefit their growth as offshore wind farms in Scotland have not only produced green energy but their bases have also acted as a new hard substrate for coral colonisation and their presence has eliminated the use of trawling in the area, meaning sustainable line fishing is more frequently used.

While your city apartment or countryside cottage may seem a million miles away from this vibrant wonder, there are still things you can do to help. Even though tracing all your seafood can still be a challenge, we can support sustainable fishing methods which do not use giant trawling nets to empty all life from the seafloor. You can also prevent plastic waste from entering our waves and conserve energy from simple switches such as energy saving light bulbs which helps reduce the contribution climate change has against corals. If you are lucky enough to visit a reef, remember not to touch the sensitive corals, anchor boats away from shallow reef areas and avoid buying those tempting coral sponges and necklaces which you know will only collect dust at home anyway.

By Neve McCracken-Heywood