Coral reefs are one of the most diverse and beautiful ecosystems on our planet. Typically coral reefs consist of a kaleidoscope of colors – vibrant reds, oranges, yellows, greens, blues, and purples. However, in some rare cases, coral reefs can take on a pinkish hue. In this article, we’ll explore how and why some coral reefs can be pink.
What causes coral to be pink?
The vibrant colors of coral reefs come from the algae that live symbiotically within the coral polyps. The specific algae that lives in most corals is called zooxanthellae, and it’s golden-brown in color. This algae gives most coral its warm brown and green tones.
However, in some cases, the coral polyps host a different species of algae called corallimorpharia. This algae contains a pink pigment called phycoerythrin that gives it a bright pink or purple color. When corallimorpharia algae lives inside coral polyps, it causes the coral to take on a pinkish hue.
Additionally, some corals have naturally bright pink skeletons. Even if they host regular golden-brown algae, their skeletons shine through to give the coral a pink look. This is especially true in corals of the Dendrophylliidae family.
Where are pink coral reefs found?
Pink coral reefs are relatively rare, but they can be found scattered across the tropics. Here are a few places around the world where you can find pink coral reefs:
| Location | Description |
| The Great Barrier Reef, Australia | Small patches of pink coral can be found here, especially bubblegum coral of the Dendrophylliidae family. |
| Veracruz, Mexico | Veracruz has vibrant pink coral reef walls covered in corallimorpharia algae. |
| The Red Sea | Pink corallimorpharia algae corals are found in various areas of the Red Sea. |
| Indonesia | Bright neon pink coral reefs are scattered around Indonesia. |
| The Caribbean | Rare pink patch reefs dot the Caribbean, like Jamaica’s Oracabessa Bay. |
As you can see, pink coral reefs are sparsely distributed in tropical waters around the world. Scientists are still working to understand the specific conditions that allow pink corallimorpharia algae to thrive. But in general, pink corals seem to cluster in warm, shallow, calm waters with high light levels.
Why are some corals pink?
We’ve established that pink corals get their color either from hosting corallimorpharia algae or having naturally pink skeletons. But why do some corals contain pink pigments while most are golden-brown or green?
It turns out the pink corallimorpharia algae may confer some benefits to the coral:
- Enhanced light capture – The pink pigments may help the algae absorb light more efficiently for photosynthesis.
- UV protection – The pink pigments may act as a natural sunscreen to protect the coral polyps from too much UV radiation.
- Defense against predators – The unusual pink color may visually deter predators like fish or starfish.
Additionally, pink corallimorpharia algae thrives under very specific conditions. In habitats where these conditions occur, the pink algae may simply outcompete golden-brown algae and take over the coral.
For corals with naturally pink skeletons, the reason is less clear. The pink pigments may be incorporated into the skeleton during growth. One theory is that it aids with light capture or photosynthesis. But more research is needed to know for sure.
Are pink coral reefs healthy?
Pink coral reefs are generally considered just as healthy and biologically diverse as coral reefs of other colors. The corallimorpharia algae and natural pink coral skeletons don’t seem to negatively impact the coral.
However, while the pink color itself doesn’t signify an issue, pink coral reefs face the same threats as all coral reefs worldwide:
- Climate change and ocean acidification leading to coral bleaching
- Destructive fishing practices like dynamite and cyanide fishing
- Pollution from agricultural and industrial runoff
- Tourism and habitat destruction
When pink coral reefs face environmental stressors like these, they are just as susceptible to decline and death as other coral reefs. The pink corallimorpharia algae and skeletons don’t make them any more resilient. Proper conservation practices are crucial for maintaining healthy pink reef ecosystems.
Can coral reef restoration efforts create pink reefs?
As coral reefs around the world suffer decline, scientists are working hard to develop effective coral restoration techniques. These efforts aim to regrow damaged reefs through methods like:
- Coral gardening – raising coral fragments in nurseries to transplant back to reefs
- Larval seeding – releasing coral larvae to settle on damaged reef structures
- Substrate artificial reefs – installing artificial reef structures for new coral growth
Could we use these same restoration methods to create new pink coral reefs?
Potentially, but it would be extremely challenging. First, the environmental conditions must be just right for pink corals to thrive. The sunlight, temperature, depth, chemistry and flow would need to precisely match the pink corals’ needs.
Second, we would need to source the pink corals – either by transplanting live specimens or obtaining pink coral larvae. Since pink corals are so rare, collecting enough to seed a reef would be difficult. This is one reason most restoration work focuses on fast-growing brown and green corals.
While scientists have discussed the idea of purposefully planting pink coral gardens, the logistics are not quite feasible yet. Perhaps in another decade or two of reef restoration research we will have the knowledge and techniques to create vibrant new pink reefs.
Conclusion
While most coral reefs dazzle us with a rainbow of colors, occasionally patches of vivid pink coral can be found gracing tropical reefs. The pink color comes from special pink algae or the coral’s skeleton. Pink coral reefs thrive under specific conditions and face the same threats as other reefs. While reef restoration efforts may someday allow us to create new pink reefs, for now these unique ecosystems remain beautiful rarities. The next time you spot a flash of pink under the waves, take a moment to appreciate one of nature’s colorful anomalies.
