Coral reefs
Coral reefs first started appearing on Earth around 500 million years ago. Although coral reefs only occupy about 0.1% of the world’s oceanic area, they are believed to be the ecosystem with the highest biodiversity on the planet, providing a home for approximately 25% of all marine species. When visiting the Two Oceans Aquarium, be sure to stop by our beautiful Coral Reef Exhibit. It is one of the first you will encounter. Also, peer into the amazing zooxanthellae exhibit. Here you will see how corals and zooxanthellae, brightly coloured microscopic algae, live together in a symbiotic relationship of colour and movement.
Coral reef gallery
Caring for corals at the Two Oceans Aquarium
Have you ever wondered what it takes to keep the colourful inhabitants of the Two Oceans Aquarium’s vibrant Coral Exhibit healthy, thriving, and looking their best? From water chemistry and filtration to dedicated maintenance and coral fragging, there is far more happening behind the scenes than meets the eye. Here is an in-depth look at everything that goes into growing and caring for our own coral.
Fun facts about coral reefs
What is a coral reef?
Corals are small colonial marine animals closely related to jellies and sea anemones. While they may look like plants or colourful rocks, they are actually invertebrates made up of hundreds or even thousands of tiny animals called polyps living together as a colony. There are two types of corals: Hard coral and soft coral. Hard corals have hard external skeletons that form coral reefs, while soft corals are flexible and resemble plants or trees. Coral reefs support a myriad of aquatic life, acting as productive nurseries for many fish species and providing homes and sustenance for other animals.
Habitats and lifestyles
It is estimated that there are around 6 000 coral species, found in both warm and cold water. The largest coral reefs are found in the clear, shallow waters of the tropics, like Australia's Great Barrier Reef, which stretches across 2 400km. Many corals have a fascinating day-and-night routine. During the day, they rely on symbiotic algae (zooxanthellae) within their tissues for energy through photosynthesis. At night, their feeding tentacles emerge to capture zooplankton and other microscopic food drifting through the water. Corals can also absorb and re-emit light in a spectacular display of biofluorescence, glowing in vivid neon colours under blue or UV light. Visitors can experience this incredible natural phenomenon in our Coral Exhibit.
Why are coral reefs important?
Coral reefs are some of the most diverse and valuable ecosystems on Earth, responsible for marine ecosystem health and biodiversity. They provide food, shelter and spawning grounds for fish and other marine animals. It is estimated that coral reefs support around 4 000 fish species. Through their symbiotic relationship with zooxanthellae, coral reefs produce a tremendous amount of oxygen, which is vital for ocean and planet health. Coral reefs protect coastlines against storms and erosion, as well as provide jobs, food, and medicines. According to the UN, over half a billion people are dependent on reefs for food, work, and coastal protection.
Climate change in coral reefs
Coral reefs are significant indicators of climate change. Increasing temperatures, lower nutrient levels, and light fluctuations stress the coral, causing them to expel the zooxanthellae. This is called “coral bleaching". With the algae gone, the coral no longer has its primary source of food, and it becomes more vulnerable to disease. Primarily due to rising temperatures, between 30% and 50% of the world’s coral reefs have been lost in the last 40 years, with 14% dying between 2009 and 2018. We can all make a difference by supporting the drive against climate change. Conserving water, supporting ecologically sound and organic farming methods and using less energy can contribute to the preservation of coral reefs.
Kids facts: Coral reefs
