Unique Facts

Pearls develop inside molluscs – including oysters, mussels and clams – whenever a foreign particle enters its shell and irritates the soft inner tissues. If the animal can’t expel the irritant, it will engage a unique defence mechanism. To protect itself from the particle, the mollusc produces a substance called nacre, or mother-of-pearl, which also lines the inner surface of the creature’s shell. Layer upon layer of the hard crystalline nacre is then used to smother the invading object so it cannot harm or contaminate the mollusc. A pearl’s iridescent appearance is due to the many layers of nacre that consist of many microscopic crystals. The thickness of one layer of calcium carbonate plates is similar to the wavelength of visible light. Some of the light passing through the top layer of nacre will be reflected, but some will continue to travel through to the bottom layer where further light is reflected. Multiple reflections interfere with each other at different wavelengths, causi

While corals may look like rocks and share several characteristics of plants, they are in fact animals. To be exact they are aquatic marine invertebrates (known as polyps) that live in the warm shallows of the clear coastal waters located around the world. A huge number of marine organisms make their home among the corals, making reefs some of the most abundant and varied habitats on Earth. Because the nutrients on which plankton need to feed dissolve better in deeper, cooler water, the warmer layers become a less attractive spot for the huge numbers of floating plankton to occupy. Therefore, the upper shallows remain warm and clear – the ideal living conditions for microscopic algae, which use sunlight to combine carbon dioxide and water to create their own food source, which they share with their coral. Corals live in partnership with single-celled zooxanthellae algae, which are also responsible for the bright colours. If the algae die the coral will turn white, a damaging effect kno

Water is not given enough credit for the role it plays in shaping Earth. Tectonic plates and volcanic eruptions are often cited as the culprits for most land features, but it is water and wave action that shapes our world’s coastlines. When a wave crashes on the shore it carries sediments that are suspended in the water, and it pushes larger sediments along the ground too.  read more : How do pearls form? What is coral? When a wave recedes it also takes sediment with it, but rarely at an equal rate. If a wave deposits more sediment than it takes away then this sediment builds up, causing coastlines to extend. Conversely, when more sediment is being removed than added, the coastline recedes or erodes. Coastal erosion is responsible for some of the most amazing landforms we know today, from the Twelve Apostles in Australia to the White Cliffs of Dover in England. The type of coastline that is created from erosion varies greatly depending on any number of factors, including the strength o