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Dive into the sea in Australia or Egypt and you almost immediately come face to face with tropical fish and a colorful world full of coral. Beautiful to look at, but what is coral actually: a collection of plants, animals or a stone construction? And did you know that coral is a kind of day cream for dolphins? Eight facts about this extraordinary natural phenomenon.
1. Coral is a living marine animal
At first glance, coral looks most like a plant and a large coral reef could be described as an underwater rainforest. But appearances threaten, because coral is a collective name for small sea creatures, also called polyps, that can build coral reefs together. All kinds of other sea creatures live here. A coral reef is therefore more like a kind of apartment building or castle under water.
2. Coral animals and algae build a coral reef together
Coral animals and microalgae have a symbiotic relationship. That means that they have been working together for so long that they can no longer live without each other. The algae live in the tissue of the coral and are an important food source for the coral animals. The microalgae convert light into nutrients and color. With this they not only give the coral food, but also the bright colors. Together, the coral and algae build limestone skeletons. Because coral lives in colonies, such a skeleton can grow into an enormous coral reef.
3. The Great Barrier Reef is the largest coral reef in the world
It Great Barrier Reef is located off the east coast of Australia and is the largest coral reef in the world. It is no less than 2300 kilometers long. You can snorkel above the coral at different spots or view the coral reef from above during a helicopter flight. Then you also see it Heart Reefa heart-shaped coral reef that is part of the Great Barrier Reef.
4. Coral mainly lives in warm areas
Coral reefs are mainly found in warm areas. In addition to Australia, the Red Sea near Egypt is also a popular place to dive and snorkel among the brightly colored coral. And you will also find a colorful collection of coral in the Caribbean. The reefs are an important habitat for other marine animals and fish, which only makes the underwater worlds more colorful and varied.
5. Dolphins use coral as medicine
An international research team discovered in 2022 that dolphins rub their skin against certain coral species in the Red Sea near Egypt. The research found that this coral releases mucus with a number of antibacterial and medicinal properties. The dolphins probably use the coral as medicine or as a prevention against skin diseases.
6. Rising temperatures threaten coral reefs
In recent decades, several factors have threatened the survival of coral reefs. The Great Barrier Reef has lost half its coral in nearly 30 years, according to a study by the Australian Institute of Marine Science. One of the biggest threats to coral is global warming.
The algae that live in the coral cannot withstand these higher temperatures. And they are just so important as a source of nutrition for the coral. In addition, algae give the coral reef its color. When they disappear, the coral reef bleaches. Eventually, the lack of algae can cause the coral to die as well.
In addition, oceans absorb carbon dioxide from the air, making the seas more acidic. Coral can also handle this badly. The more CO2 there is in the air, the greater the threat to the coral.
7. Sunscreen can also damage coral
Tourists like to snorkel and dive above and between coral reefs, but therein lies a danger. Some sunscreens are bad for the sea and also for the coral. How did that happen? Sunscreen contains substances, including oxybenzone, which cause an increase in viruses in the water. This kills the algae that live in the coral and bleaches the coral reefs.
8. Coral is resilient and can recover
But, there is also positive news. A 2022 research report from the Australian Institute of Marine Science shows that parts of the Great Barrier Reef are recovering. The institute found the largest coral cover in 36 years in the north and center of the reef.
How did Australia’s coral reef grow again? The researchers attribute this mainly to the lack of large cyclones and storms. As a result, conditions were relatively calm and the coral had a chance to recover.