Coral reefs

Did you know that more wildlife lives around coral reefs than in any other part of the ocean? Find out more about these important ecosystems in our coral reef facts… What are coral reefs? When you look at a coral reef, you might think that you are seeing a group of colourful rocks. But don’t be mistaken! Reefs are actually made out of living creatures called coral. • Where are coral reefs found? Coral reefs can be found all over the world! However, most coral reefs grow in shallow, clean ocean waters on either side of the Equator, because they need sunlight and warm temperatures all year to survive. Some famous coral reefs include the Great Barrier Reef in Australia, the Amazon Reef in Brazil and French Guiana, the Tubbataha Reef in the Philippines and the Miami Terrace Reef in the United States. The “Heart Reef”, which forms part of the Great Barrier Reef in Australia • Quick facts about coral reefs… • – Coral have growth rings, just like trees! • – The first coral reefs formed on Earth 240 million years ago. That’s before the dinosaurs were alive! • – Most coral reefs today are between 5,000 and 10,000 years old. • – There are more than 800 different types of hard coral around the world. • – The Great Barrier Reef is the largest reef system on Earth. You can even see it from space! Life in coral reefs Lots of different types of sea creatures call coral reefs their home – giant clams, starfish, eels, cuttlefish and many, many more. The reefs provide this diverse range of ...

Although seas are important waterways, fishing grounds, and so much more, they also host some of the most diverse ecosystems, including As the name suggests, coral reefs are formed when the coral skeletons cluster in groups to form colonies. These coral colonies are held together by calcium carbonate deposits present in the seawater. Most reefs form best in clear, shallow, warm, and agitated waters. Although the first coral reefs appeared over 400 million years ago, most of the existing ones are less than 10,000 years old. The world's Distribution And Location Source: Spalding MD, Ravilious C, Green EP (2001) World Atlas of Coral Reefs. University of California Press, Berkeley, USA. According to the UNEP World Conservation Monitoring Center, coral reefs cover about 109,800 284,300 km 2 or less than 0.1% of the World Ocean's total surface area. The area covered by the reefs is almost the size of Cuba or half the size of France. The largest coral reef area (about 92% of the total area) is within the Indo-Pacific region, a region comprising the Pacific, Indian Ocean, Southeast Asia, and the Red Sea. Of the reefs in the Indo-Pacific, 32.3% are in Southeast Asia, while 40.8% are in the Pacific. The Caribbean and the Atlantic area accounts for about 7.6% of the world’s coral reefs. The Indian Ocean accounts for up to 60% of the global coastal reefs, the Pacific Ocean 25%, and the West Atlantic 15%. The Hawaiian Island, Madagascar, and the Philippines also have coral reefs. In So...

Marine ecosystems are aquatic environments with high levels of dissolved salt, such as those found in or near the ocean. Marine ecosystems are defined by their unique biotic (living) and abiotic (nonliving) factors. Biotic factors include plants, animals, and microbes; important abiotic factors include the amount of sunlight in the ecosystem, the amount of oxygen and nutrients dissolved in the water, proximity to land, depth, and temperature. Sunlight is one of the most important abiotic factors for marine ecosystems. It’s so important that scientists classify parts of marine ecosystems—up to three—by the amount of light they receive. The topmost part of a marine ecosystem is the euphotic zone, extending down as far as 200 meters (656 feet) below the surface. At this depth, there is sufficient light for regular photosynthetic activity. Most marine life inhabits this zone. Below the euphotic zone is the dysphotic zone, which can reach from 200 to as deep as 1,000 meters (656 to 3,280 feet) below the surface. At these depths, sunlight is still available, but only enough to facilitate some photosynthesis. Below the dysphotic zone lies the aphotic zone, which does not receive any sunlight. Types of Marine Ecosystems Scientists divide marine ecosystems into several broad categories, although there are discrepancies depending on the source about what qualifies as a marine ecosystem. The number of marine ecosystems is actively debated. Although there is some disagreement, several...

The Great Barrier Reef, which extends for over 2,300 kilometers (1429 miles) along the northeastern coast of Australia, is home to over 9,000 known species. There are likely many more—new discoveries are frequently being made, including a new species of branching coral discovered in 2017. This richness and uniqueness make the reef crucial for tourism and the Australian economy—it attracts at least 1.6 million visitors every year. Yet the reef’s true value, its biodiversity, extends far beyond dollars and cents. The Great Barrier Reef consists of about 3,000 individual reefs of coral, and the biodiversity they contain is remarkable. There are animals you would probably recognize, such as dolphins, turtles, crocodiles, and sharks. There are also venomous sea snakes, brightly colored worms, and large algae. These species interact to form a complex and delicate ecosystem dependent on the coral reef for survival. Yet today the coral—and therefore all the organisms that depend on it—is gravely at risk. Coral is made up of many small animals. These tiny animals build a hard external skeleton to make the vibrant structures that we recognize. When healthy, coral has a symbiotic relationship with algae. The coral produces fluorescent chemicals that protect the algae from bright sun—almost like a sunscreen. The algae use photosynthesis to harness solar energy to make sugars. In this way, the algae provide food and oxygen (a byproduct of photosynthesis) for the coral, and the coral pr...