Coral reefs are the most complex and biologically diverse marine ecosystem in existence. They are made up of the decomposed skeletons of a large colony of polyps, better known as corals.
Corals have a symbiotic relationship with the microscopic algae called Zooxanthellae, which helps them grow in areas exposed to sunlight to promote photosynthesis and at 70-85°F (22-29°C). They secrete more calcium carbonate substrates which settle as corals grow and die on rocks. This continuously attracts more corals thus forming a coral reef.
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Types of Coral Reefs
Fringing reefs – are the most common type of coral reef and project outward from the shore/ coastline of islands and continents creating shallow lagoons.
Barrier reefs – also border the coastline but they are separated by wide areas of water. At their shallowest point, these reefs reach the surface of the water and form a “barrier” that stops boats from going across. The Great Barrier Reef around Australia is the biggest and most well-known in the world.
Atolls – are fringing reefs surrounding a sunken underwater volcano while the coral grow upwards and creates multiple layers with a central lagoon.
Patch reefs – are small and isolated, usually existing between fringing and barrier reefs on an island platform or continental shelf.
• Coral reefs support the life of thousands of marine plants and animals including crustaceans, algae/ seaweeds, bacteria, fungi, and over 4,000 species of fish.
• Reefs create millions of dollars of revenue each year and provide work for millions of people in over 100 countries.
• They also provide stability to the surrounding land which prevents erosion.
• They provide food for people living near coastal areas, especially on islands found in the Caribbean and throughout South East Asia.
• They provide a natural barrier of protection to coastal communities and beaches during natural disasters like hurricanes.
• In the medical industry, they develop and test potential treatments for various illnesses and diseases based on observation of the animals inhabiting the coral reef ecosystem.
Factors that Affect Coral Reefs
• Coral mining -mining of coral to produce limestone or cement substitute, lime for raising soil pH and material to make jewelry etc. This destruction effectively leads to decreasing economic gains from fishing and other endeavors.
• Pollution -the use of pesticides, improper sewage disposal, silt water runoff etc. can severely affect the quality of sea/ ocean blocking sunlight and therefore damaging the relationships that exist among the marine wildlife that compose the coral reef ecosystem.
• Overfishing and bad fishing practices- intense fishing, blast fishing and use of harmful chemicals to catch fish destroys the reefs nutrient supply and physical structure.
• Ocean acidification -the release of large amount of carbon dioxide in the atmosphere from the burning of fossil fuels. This leads the coral’s inability to produce the calcium carbonate exoskeletons that they rely on for shelter.
• Coral bleaching -occurs when water temperatures rises due to global warming. Corals expel the colorful algae cells living inside them and providing them food. This leads to the corals dying. Bleached coral becomes a habitat for worms and sponges which burrow into the coral making it honeycomb like. This increase in fragility makes corals more susceptible to breakage and loss of protection during storms. Dead reefs cannot support all the marine plants and animals lives in the ecosystem.
What We Can Do To Preserve Them
• Regulating the fishing practices used in the area surrounding the reef
• Minimizing coral mining
• Treating/ purifying sewage strenuously to prevent spread of toxins and bacteria
• Preventing silt water run off which blocks sunlight
• Establishing coral reef reserves to protect the ecosystem
As you can see, by putting in the efforts to save coral reefs, we can positively affect thousands of people around the world and millions of sea creatures.
Alexandra grew up dreaming of being a great science explorer. She always wanted to travel the world and explore some of the greatest science mysteries of the times. After high school, she studied chemistry in college and spent most of her summers working on research projects alongside her professors. It was there that Alexandra got clarity about what she wanted to do in the future. She now works full time in science research at a teaching university and is planning to go to medical school in a few years. She likes to stay up-to-date with the latest discoveries in science and share her love for science through her writing.