Coral are some of the most fascinating but misunderstood animals within the world’s oceans. These plant-like animals display symbiotic relationships with the creatures that have made coral reefs their homes. The first coral developed around 650 million years ago, with coral reefs being the largest living structure in the world – just look at the Great Barrier Reef!
Despite only making up 11% of the ocean floor, without coral up to 25% of marine species would simply cease to exist, which is why we must do everything in our power to protect these hugely important areas of the ocean.
With that in mind, let’s explore the different species of coral and what makes them unique!
What is coral?
Coral are a type of translucent marine invertebrate within the Cnidaria phylum of animals. Over 6,000 animals fall into this phylum which also includes anemones, sea fans, and jellyfish.
Animals are grouped into phyla based on shared morphology and evolutionary ancestry, demonstrating just how much evolution can cause animals to differ over millions of years despite sharing a common ancestor.
Coral-building corals deposit calcium carbonate skeletons that gradually build up over time. From a distance, coral reefs simply look like rocks, but a closer inspection will reveal their tiny coral polyps.
Coral feed using their stinging tentacles to catch prey, but they primarily rely on algae called Zooxanthellae that live within their cells, called nematocysts, to use energy from the sun through photosynthesis in order to provide them with valuable nutrients.
What is coral made of?
Coral by themselves are translucent, with algae providing the beautiful colours that we associate with coral.
As well as this, coral duplicate themselves and interconnect to form vast colonies in the ocean which can grow up to several tonnes.
There are two types of coral that inhabit the oceans, here we’ll dive into the differences between the two and explore a few species of both hard and soft coral.
Hard coral are what you’re probably thinking of when you hear the word coral. Hard coral (hermatypic corals) form hard exoskeletons made of calcium carbonate and group together to form coral reefs. The animals themselves are still very soft, but they form hard reefs which is where they get their name from.
Hard coral species
Let’s explore the species that make up the hard coral reefs we know and love.
Staghorn coral
As the name would suggest, staghorn coral (Acropora cervicornis) is named after the horns of a stag, which are long and slender. This coral is known to grow up to five feet high and spread across 30 feet in the ocean, feeding on tiny marine animals in the shallow waters of Florida, the Bahamas and the Caribbean.
Elkhorn coral
Elkhorn coral (Acropora palmata), is much broader than staghorn coral, closely resembling the larger antlers of an elk. They inhabit the same areas of the Bahamas, Caribbean and Florida as the staghorn coral, competing with them for the same resources such as space, light and zooplankton. Caribbean spiny lobsters, parrotfishes, and tube blennies are reliant on elkhorn coral to provide their habitat.
Brain coral
Continuing the theme of naming these animals after objects they resemble, there are no prizes for guessing what this coral looks like! This name encompasses a couple of families of coral that both look like brains – Mussidae and Merulinidae. Brain coral are usually oblong shaped and resemble colourful brains! These remarkable animals can live for up to 900 years, growing and developing the entire time.
Lettuce coral
Known for their distinctive, lettuce-like appearance, the lettuce coral (Agaricia agaricites) inhabits waters in the shallow waters of the tropical western Atlantic Ocean and the Caribbean Sea. These coral are nocturnal and mainly choose to feed at night, although during overcast days they can get a little confused and think that it’s nighttime.
Soft coral
Soft coral is made up of polyps, much like hard coral, but unlike hard coral, they do not produce the calcium carbonate secretions that build up huge reefs. For this reason, soft coral are usually solo animals that live among other species’ reefs.
Sea fan
Sea fans (Gorgonians) are beautiful creatures that are usually bright colours thanks to the algae that live within their cells. They’re located in oceans across the world, feeding on tiny plankton as well as getting up to 70% of their energy from photosynthesis. Many sea horses are known to call sea fans home and have even adapted to resemble each other as a way of camouflage.
Sea strawberry
The adorable sea strawberry (Gersemia rubiformis) is a small red coral that looks remarkably similar to the fruit that it’s named after when grouped together. With striking red colours, juvenile lobsters and basket stars use these coral as bases to grow. Although they only grow up to about 8 inches, these coral play a huge role in maintaining the ecosystems they inhabit.
Bubblegum coral
Because of its bulbous, pink branches, Paragorgia arborea is frequently called bubblegum coral. This coral lives in cold water and is slow to grow but has an extraordinarily long life of a few hundred years.
Carnation coral
There are over 250 species that come under the genus Dendronephthya, which are collectively called carnation coral. Known for their bright colours and spiky-looking exterior, these soft coral are exceptionally beautiful but are exceptionally difficult to keep in aquariums, needing an almost constant supply of plankton to survive.
What is coral bleaching?
Coral bleaching is the process of coral rejecting the algae that give them their extraordinary colour. The process is caused by external stresses to the coral, such as high temperature, salinity, acidity or other factors.
Although not deadly in itself, a coral without photosynthesis may lack the energy to be able to grow, reproduce, and feed. In time, it may die of starvation.
We can stop this by protecting the oceans that coral call home, helping to keep the delicate ecosystem balanced. This can be achieved in a few ways:
- Recycle and dispose of rubbish properly
- Minimise the use of fertilisers
- Utilise more public transport
- Save energy at home and at work
- Be conscious when buying aquarium fish
- Suncream
By taking on board these actions, you can play a part in the conservation of marine life such as coral. Writing to public officials may also demonstrate to them that this is an issue of significance and may affect public policy in the right direction.
It’s important to remember that coral is responsible for producing around 50% of the world’s oxygen, but also absorbs a third of CO2 produced by fossil fuels – highlighting just how important coral is to our ecosystems.
Coral really are one of the most fascinating creatures that inhabit the oceans, with more than meets the eye. Their exceptional growth helps to sustain millions of other sea creatures and simply cannot be replaced, it’s little wonder that they are called the rainforests of the ocean.
To see this beautiful animal up close, pay a visit to the Tropics Exhibit at Deep Sea World by booking your tickets now!