The Importance of Coral
The Importance of Coral
Today, I want to talk about coral. Now coral reefs are a topic tropical marine biologists love to go on and on about. Personally, for a while I thought they were obsessed. But after learning more and getting it…well they are still obsessed, but with good reason. Despite looking boring, coral is really important and really cool. Hopefully you’ll start to see a little bit of why by the end of this post.
Setting the Stage
Let’s start off with the basics. What is coral? Despite looking like a rock, Coral is an animal (technically a colony of animals). Corals are closely related to jellyfish, and while there are tons of corals, when scientists say it, they are typically referring to hard, stony corals. When I say corals these are what I’m referring to.
Corals are found in the tropics, so areas like my home Jamaica traditionally have coasts full of coral. They have reasonably strict living requirements:
Corals prefer warm(but not hot) water
They need clear sunlight, and so prefer shallow water
Seawater without any freshwater
Water with sufficient Calcium to build their skeletons
They tend to accumulate in coral reefs, rocky formations which, personally I think are the most beautiful environment in the sea. These reefs are formed by corals growing atop each other.
Why do these matter?
Not only are these reefs absolutely gorgeous, they are homes. The nooks and crannies made by the corals growing serve as habitat for the fish and other organisms that live on the reef.
And believe me, There’s a lot of organisms on the reef, the usually quoted figure is that 25% or 1 in 4 marine animals spend some part of their lives on the reef. That includes tons of the fish we eat. In fact, here in my home country at least, pretty much all our traditional fish are reef dwellers.
This seems like a good place to talk about another thing corals do. While they are animals (I wouldn’t lie to you), they do look like rocks. They are tough enough to break waves coming in to shore. I’ve been on both sides of a reef helping students and we can all confirm, the forereef (the side facing out to the deep sea) is way rougher than the backreef (where the waves have been broken). This applies to regular waves, but also storm surges. A healthy reef protects what’s behind it, and what’s behind it is often our land and home and buildings.
So by now, you can see corals help give fish(or seafood) places to live and grow, and protect the shore from storms and harsh waves. That’s already plenty. But I’ve mentioned they’re gorgeous, and people (like me), will pay money to go dive and see the reef and its residents.
So it seems like corals are a win-win-win. Which means this is where I drop the bad news.
The Bad News
Remember when I said coral was an animal? It is, but its also more. If you want to get technical, what we refer to as coral is usually a partnership between a jellyfish-like animal (polyp), and tiny plants (zooxanthellae or dinoflagellates). The plants give the coral its gorgeous colour, and provide it with food. In exchange, the corals provide them with homes and protection. And those plants do that job really well. Under normal circumstances, the plants provide all the energy the coral needs and it barely has to feed on things drifting by in the water with its tentacles. Those plants are the reason the corals need clear, shallow water and plenty of sunlight.
But it can backfire. When temperatures get too hot, or the corals are otherwise stressed they eject their tiny plants. Like I said, the plants give them their vibrant colour, so they turn a haunting, bony pale white when they are lost, a process called bleaching. They don’t die immediately, and if the stressor subsides, they can even take back up new plants into their cells. But if it persists. They will die.
And reefs take centuries to grow. The heat contributes to bleaching. In recent years, we’ve had bleaching events back to back to back. I will likely never see a reef the way my mentors did, and yet, that I may be one of the last divers to see a live reef.
We’re fighting back. The scientists, conservationists and other groups are trying, I personally know several who are, but Its a scary and sobering thought that I may be one of the last humans to dive a reef, and see an ecosystem that quite literally built and sheltered my island.