The sea.
Those two, simple, monosyllabic words conjure up a myriad of images, sounds and smells. The glistening sun reflecting off the surface of the water, sparkling like a thousand dazzling diamonds. The sound of the waves creeping up and down the sandy shores or crashing against a rocky cliff. The smell of saltwater wafting on the air, carried by a light breeze that slightly dampens your hair. Or even the goosebumps you get when swimming in a deeper, darker part and something touches your foot…
But the sea is so much more than the happy summer memories, or the picturesque backgrounds on your phones. It is home to a whole ecosystem in its own right. You will find many beloved creatures, from dolphins and whales, to brightly coloured fish (such as the clownfish, made popular thanks to Disney’s “Finding Nemo”, alongside his many aquatic co-stars). But the subject of this article is the less famous: coral.
So, What Is A Coral?
Often mistaken for a plant, this calm creature is divided up into soft (with an internal structural support called spiracles) and hard (with a calcium carbonate external skeleton) corals. Hard corals are themselves divided up into two types: tropical corals and cold-water corals. (NB This article focuses on hard corals, so for future reference, all corals mentioned belong to the branch of hard corals).
Tropical corals live in symbiosis with microalgae (zooxanthellae) which are present in the coral tissue and can support up to 80% of the coral’s energy needs. The coral provides the algae with shelter and in return, the zooxanthellae feed themselves and the coral by means of photosynthesis. This means that they are found in shallow waters (0 to 40m deep) as the sun’s rays are needed. Distributed in the tropics and subtropics, they are found in warm waters (25 to 32°C) and are especially vital in low-mineralised waters as, these waters are low on plankton and plants cannot grow. This means that the coral reefs are the only refuge for marine and animal species that would otherwise disappear.
Cold-water corals are found in deeper waters (20 to ca. 1400m deep) and – as the name suggests – colder waters (under 14°C). This means that, given the weak light, the symbiosis with the zooxanthellae and their photosynthesis is not possible. Instead, they feed on nutrients found in the water or by capturing particles of plankton with their tentacles. These corals can be found in the 5 oceans and, thanks to advancing technology and the variety of devices needed to explore these depths, more and more knowledge is being gained on them.
What Role Do They Play?
It is needless to say how important corals are for the sea and ocean’s ecosystem as well as for us human beings. Other than the fact that more than 50% of the oxygen we breath comes from our oceans (for which corals play an essential role in their health), there are more, perhaps, surprising benefits to having healthy corals in our oceans and seas. Tropical corals cover only 0.2% of the ocean’s surface and yet they provide shelter, food and grounds for reproduction for 25% to 32% of all marine species. They also provide coastal protection (e.g. reducing damages from storms – flooding), bring in a substantial amount in tourism and provide food security through local fishing. Cold water corals are also important for fishing as they provide refuge, habitat and breeding grounds for many fish and other species of the food web. This provides economy for the fishing industry and food security for the local fish consumers. They have also been found to produce compounds with anti-inflammatory and anti-viral capacities and even potential anti-cancer properties. The full extent of how much we can benefit from them is not yet understood as research related to deep-water corals is only beginning to grow.
What Threats Do They Face?
What is certain is that corals and coral reefs are amongst the most threatened of all marine ecosystems and this threat is human-caused.
- Rising water temperatures and ocean acidification weaken corals and their skeletons and make them susceptible to bleaching, disease, breaking and slow down their growth rate. For tropical corals, bleaching means that they “expel” their zooxanthellae and eventually die from a lack of resources. Cold water corals whose skeletons break due to ocean acidification, impacts the entire ecosystem relying on them for shelter, a nursery and food.
- Commercial fishing destroys vast colonies by trawling and towing fishing gear on the seabed, destroying in a matter of seconds areas built and grown over the span of 8000 years. Dynamite fishing and cyanide fishing are a major threat to coral reefs as well as the many other species present in the ecosystem.
- Careless divers and tourists also damage corals by removing/taking them, damaging them with flippers and diving gear, or by dropping boat anchors on them.
- Oil and gas exploration heavily damages corals, especially in the case of oil-spills.
- Plastic waste discharged at sea, alongside abandoned fishing and diving gear is yet another threat to corals.
Deep sea corals grow very slowly so it can take centuries to recover from these damages, if they manage to recover at all… 40% of the reefs have disappeared since the 1970’s and 90% of the remaining reefs could become extinct by 2040. But we don’t have to stop there, we can still do our part to prevent further destruction and ensure as good a future for our ecosystems as possible!
What Can We Do?
We can avoid eating slow-growing deep-water fish or choose products from sustainable fisheries. Avoiding products (e.g. toiletries) containing microplastics such as Polyethylene and Polypropylene (apps such as “Yuka” can help scan ingredients and tell you what they are) and recycling are easy ways of ensuring our oceans stay as plastic-free as possible. If you wish to go a step further, buying plastic-free/zero-waste products and shopping in places where you can bring your own containers is made possible thanks to different apps (e.g. “Refill”) which help you locate these shops. Participating in beach clean-ups and volunteering or donating to certain organisations (e.g. Coral Guardian) is another great way to actively help corals by growing, transplanting, monitoring and caring for them.
Coral Guardian
Coral Guardian permits you to adopt a coral either near Punta de la Mona in Spain or near Hatamin island in Indonesia. For a small donation, you can name a coral which will be transplanted in the location of your choice and you then receive a certificate complete with co-ordinates (should you want to go and visit your coral and see how it’s getting along), the name of the person who transplanted it, a picture and the species’ name. You can also ask to receive monthly updates and information on your adopted coral, on their projects to clean the sea and teach the locals to fish sustainably, the concrete and long-lasting impact on the local lives, the awareness raised and the scientific monitoring and data collected.
In short, sometimes a small change of routine can go a long way, just as a small creature can do so much for our planet. So, let’s do our best to respect and take care of each other.
Photo credit: Coral Guardian.
