I think we can all appreciate corals for their lollipop colours and assorted shapes, but there is so much more to them than meets the eye (ha!). They’re not pretty rocks, but complex creatures of our seas. I’ve put googly eyes on them to help remind us that although they may look inanimate, corals are animals, and they play a vitally important role in our oceans.
And if you want more googly eyes, check out the tumblr ‘Deep Sea Fauna… With Googly Eyes‘ – they’ve inspired this post!
#1 Corals can sting, dissolve and kill their neighbours.
Corals are in competition for space – there’re only so many hard surfaces (in the sun, in warm water with agreeable waves, currents and water clarity) for them to grow on. To outcompete those around them some corals will secrete a necrotic mucus, which literally dissolves the flesh of their victims. Others use ‘sweeper tentacles’, long tentacles with stinging cells attached that aggressively attack neighbouring corals to damage their tissue.
#2 Coral reefs are home to 25 – 33% of ALL marine species!
Coral reefs make up just 0.2% of the world’s oceans and comprise a total land size smaller than France! And yet, a huge percentage of our marine species live here. Scientists’ best guestimates predict a quarter to a third of all our marine species call coral reefs home.
#3 Most corals live in colonies.
Those big mounds of coral you’re used to seeing are not one single animal but many small polyps. These coral polyps are all animals, genetically identical to each other, forming one coral colony.
#4 Some corals live alone and can walk around.
But not all corals live in colonies with a bunch of mates around – some are wandering loners. Mushroom corals, like the one below, are just one single animal and can shuffle through the sand and can even flip themselves over if they become upturned.
Note: It can take like six hours for them to do so though. I’m still impressed.
#5: A coral’s mouth is also its bum.
The little animals that make up corals, the polyps, are like teeny sacs. They’ve just one opening for all their intake and expulsion.
#6 Some humans receive coral bone transplants
Hard corals produce a calcium carbonate skeleton that’s very similar in structure to our own human bones. So similar is its composition, that it’s an impressive bone substitute for those needing bone transplants and since the 80s, there have been people walking around with some coral skeleton in their human skeleton.
#7. Coral polyps have algae living inside them, making them food.
In just one cubic millimetre of coral tissue there can be up to 30, 000 algal cells – all of which can photosynthesise to give a coral energy. Called zooxanthellae, these specialised algae living inside the corals can produce up to 90% of their energy needs. In return, the zooxanthellae get a nice home.
#8. Corals turn white when they bleach, because the zooxanthellae get kicked out.
Not only do the zooxanthellae provide most of the energy for a coral, their pigments give the coral their colour too. When corals become stressed, such as when water temperature is just 1 – 2 degrees higher than the normal maximum, the zooxanthellae stop being able to photosynthesise and the coral is forced to expel them – vomiting them into the sea and turning them white.
#9. So be a voice for corals and help reduce the effects of global warming to prevent bleaching events!
The only way we can really save corals is to reduce the effect of global warming. So be a pal to our corals and cut down your carbon footprint. Give up straws, recycle more, take a tote bag to the supermarket – all good habits to foster.
#10. BONUS SPONGE: Because sponges are animals too.
Hope you enjoyed these googly-eyed corals (and sponge!). They were so fun to edit – have a go too and if you do, send them my way because I’d love to see them! Finally, if you’d like some more oddness, follow me on Instagram/Twitter @OddOrganisms.
Demers, C., Hamdy, C. R., Corsi, K., Chellat, F., Tabrizian, M., & Yahia, L. H. (2002). Natural coral exoskeleton as a bone graft substitute: a review. Bio-medical materials and engineering, 12(1), 15-35.
Hoeksema, B. W., & De Voogd, N. J. (2012). On the run: free-living mushroom corals avoiding interaction with sponges. Coral Reefs, 31(2), 455-459.
Knowlton, N., Brainard, R. E., Fisher, R., Moews, M., Plaisance, L., & Caley, M. J. (2010). Coral reef biodiversity. Life in the World’s Oceans: Diversity Distribution and Abundance, 65-74.
Lapid, E. D., Wielgus, J., & Chadwick-Furman, N. E. (2004). Sweeper tentacles of the brain coral Platygyra daedalea: induced development and effects on competitors. Marine Ecology Progress Series, 282, 161-171.
Sumich, J. L., 1996. An Introduction to the Biology of Marine Life (6th ed.). Dubuque, IA, USA: Wm. C. Brown. pp. 255–269.