When you hear the phrase ‘coral reefs’ the first thing that springs to mind is probably an image of a vibrant underwater world filled with intricate coral structures surrounded by schools of tropical fish.
Yet, these structures do so much more than simply add to the aesthetics of the underwater world. In fact, without corals, entire reef ecosystems would collapse, with devastating effects on the marine world.
As well as supporting marine life, coral reefs also support humans in many ways, yet despite this, corals remain poorly understood by most people.
So, let’s take a closer a look at what these mysterious structures actually are as well as the importance of coral reefs.
What Exactly are Corals?
Did you know that corals are actually living animals?
We wouldn’t be surprised if you didn’t. They certainly look as though they might be some kind of plant or even a rock.
An individual coral animal is called a polyp, which is a super small and very simple creature. Polyps belong to the same phylum as jellyfish – which makes sense because they look a bit like an upside-down jellyfish (with the tentacles in the air).
Most corals are what we call ‘colonial’, which means that they team up with thousands of other polyps to form the final structures that we see on reefs.
Although polyps use their tentacles to catch some food as it floats by, and then pass it down into their stomachs (which are also their butts…), this isn’t their main food source. The hard corals that we see on our reefs form a clever partnership with a certain kind of algae (called zooxanthellae) to make sure that they don’t go hungry.
Ideally, algae want to use the light of the sun to feed (through photosynthesis), but this can be hard work when you’re floating around the ocean and hungry fish might snap you up at any moment. That’s why the algae love hanging out inside their polyp friends – they can sit still and soak up the sun without fear of being eaten.
As they feed, they release waste products… but this waste is actually food for the polyps, who love having their algae friends come and stay with them because they get a free dinner – in fact, algae can provide coral with as much as 90% of their food.
And guess what? As the polyps feed, they release waste that the algae use to feed… so this is definitely a mutually beneficial relationship.
But hang on… if polyps are like teenie jellyfish, how do they form the solid structures that we see on our reefs?
Well, as hard corals grow, they build limestone houses around themselves for protection, which gives them their incredible structures. Interestingly, these structures are actually colorless, but the algae that take up residence within polyps can be various colors, and this is what gives coral its final color!
So, in a nutshell, corals are miniscule animals that group together, produce mineral structures, and take up brightly colored plants to help them feed… got it?!
The Importance of Coral Reefs
Ok, we’ve established what coral are, but why are these complicated creatures so important?
…for Marine Life
Coral reefs are thought to cover just a tiny portion of the sea floor – less than 1% in fact – yet they play a huge role in supporting marine life.
Around 25% of marine life will depend on coral reefs at some point in their life – usually when they’re small vulnerable juveniles that need somewhere to hide!
What’s more, the reefs are home to almost one third of fish species. So, despite covering such a small area, the reefs are crucial for maintaining abundant and diverse marine life.
…for Protecting our Coastlines
Coral reefs act as physical barriers that protect our shorelines from the power of the ocean by absorbing much of the impact of heavy waves, particularly during storms. It is thought that as many as 200 million people rely on this protection to live stable lives by the coast.
The Maldives learned the hard way that replacing these natural fortifications is an expensive task. After the destruction of their reefs, they found out that it costs an astonishing $10 million (USD) per kilometer (0.62 mile) of artificial protective wall!
…for Human Health
Antibiotics have done a great job of protecting humans from nasty infections since penicillin was discovered back in 1928. Unfortunately, pathogens are cottoning on to our defenses, and many of them are now resistant to the antibiotics that we rely on for our health.
The good news is that the ocean represents a treasure chest of potentially lifesaving medicines yet to be discovered. So far, our reefs have brought us painkillers from cone snail venom, fluorescent markers (used in molecular science) from jellyfish, drugs used to treat cancer and AIDs from sponges, and certain corals have even been used in bone replacements thanks to their similar pores – so who knows what other medicines our reefs have in store for us?
…for Our Economies
Finally, divers, snorkelers, and anglers spend thousands of dollars each year visiting coral reefs around the world. This influx of tourists to coastal areas supports local businesses, like hotels, restaurants, and tour operators, and also ensures a steady supply of jobs in the area.
This is clearly evident in Australia, where the Great Barrier Reef is to thank for a national economic contribution of $6.4 billion and the creation of 64,000 jobs.
On top of that, reefs also contribute to the huge amount of revenue generated through commercial fisheries – for instance, it’s thought that the US makes more than $100 million annually from its reef-based fisheries. Plus, they provide food to small coastal communities.
The Future of Coral Reefs
If you’re an ocean lover, we’re sure you’ve already heard about the troubles our reefs are facing. Key threats include the effects of overfishing, climate change, and pollution, and the worst-case-scenario predictions estimate that an astounding 90% of our reefs will be dead by 2050. This sounds pretty scary, especially considering the importance of coral reefs for our coastal protection, health, food supply, and economies.
So, is there are any hope for our reefs? Well, this depends. It certainly won’t be easy, but there are groups of people around the world working tirelessly to protect our reefs.
Researchers have some corals that are more resilient to rising temperatures than others, and coral restoration projects have kicked off around the world to repopulate reefs with these hardy populations. Scientists have also been exploring ways to genetically modify corals so that they can better stand up to the effects of climate change.
What’s more, clean energy and diets containing less meat are on the rise, both of which will massively cut back on emissions and their effects on the ocean. Plus, more and more people are opting to live plastic-free lifestyles (or at least ‘less-plastic’ lifestyles), and fishermen are under increasing governmental pressure to employ sustainable fishing practices – and consumers are choosing to harness the power of consumer choice and only purchasing sustainably caught fish.
So, all is not yet lost and there’s plenty you can do to help. If you’re interested in learning more about corals and the threats they’re under, then why not check out the ‘Chasing Coral’ documentary (available on Netflix).