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Ecology of Coral Reefs

Ecology is the study of organisms and their relationships with each other and their world.

Different organisms in the ocean rely on the coral reef for shelter and food (Ecology, n.d.). Let's dive into a few different living things you might recognize and how they rely on the reef to survive!

Also, living things like the ones below will be called organisms throughout the rest of the page! That is what a scientist calls a living thing!

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Organisms:

  • Clownfish

  1. There are 30 documented species of clownfish and they all need the coral reef for shelter and protection from predators (Clownfish | National Geographic, 2011).

  2. Most species of clownfish have a special relationship with an animal called an anemone. Different species of anemones have different species of clownfish that will live in them. In return for protection from predators, the anemone will get to eat bits of leftover food that the clownfish eats or the clownfish will even lead a fish to the anemone that will then become its food (Clownfish | National Geographic, 2011) (Clownfish Facts, n.d.). 

  3. Each species of clownfish has mucus covering their entire body which protects them from the stinging cells of the anemone (Clownfish | National Geographic, 2011).

  4. The most common clownfish that you think of when it comes to coral reefs is the ocellaris clownfish, which is the same fish that Nemo is based on from Disney and Pixar's films Finding Nemo and Finding Dory.

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  • Moray Eels

  1. Eels are a type of fish that look very snake-like, and they live within cracks and crevices inside of the reef (Green Moray Eel, n.d.).

  2. There are over 200 recorded species of moray eels that live in coral reefs around the world (Green Moray Eel, n.d.). 

  3. Morays are also well known for their toothy grin, which is visible because of how the moray takes in oxygen. The moray eel will open and close its mouth repeatedly to take in water into its gills, which then takes out the oxygen it needs and transfers to the bloodstream and the remaining water exits out the round gill slits that are on both sides of the head (Green Moray Eel, n.d.).​

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  • Octopus

  1. The octopus is a member of the invertebrates, meaning they do not have a backbone or spine. Octopi have no bones at all (Octopuses, Facts and Information, n.d.)!

  2. There are over 300 species of known octopi that inhabit our planet and some of them live on coral reefs(Octopuses, Facts and Information, n.d.). 

  3. Octopi can twist and bend their body into whatever shape they need to fit into the smallest of spaces. Octopus actually can slip through spaces that are very small and are only limited by the hardest part of their body, their beak (Octopuses, Facts and Information, n.d.)!

  4. The Caribbean Reef octopus as shown in the pictures above hunts at night and can also completely change the color of their body using specialized cells called chromatophores (Caribbean Reef Octopus - Oceana, n.d.).

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  • Cleaner shrimp

  1. Many species of cleaner shrimp live in various coral reefs around the world. The Pederson Cleaner Shrimp in the first photo can live in several different anemones in the Caribbean Sea and even up into the reefs of the Florida Keys (Pederson’s Cleaner Shrimp, n.d.).

  2. Certain species of cleaner shrimp will live in spots on the reef with other animals called cleaning stations. The cleaner shrimp is small enough to crawl into spaces and deep clean large animals of their parasites. Some different species of animals that use cleaning stations are sharks, sea turtles, eels, and other large animals (Pederson’s Cleaner Shrimp, n.d.)(Pacific, n.d.)! 

  3.  All cleaner shrimp are invertebrates since they have a hard shell that encases their organs and muscles. They are also called a crustacean because of their hard shell and the pincers that they use to grab food items (Invertebrates | NOAA Fisheries, n.d.).

  • Parrotfish

  1. On Earth, there are 80 documented species of Parrotfish (Parrotfish | Animals | Monterey Bay Aquarium, n.d.)​!

  2. The Parrotfish is named for its mouth, which looks like a parrot’s beak, but it has fused teeth! This adaptation, a change that better suits the organism in its environment, allows parrotfish to eat coral from the reef as well as the algae that live with the coral polyps (Parrotfish | Animals | Monterey Bay Aquarium, n.d.)​.

  3. These fish actually will produce waste that makes up the coral reef sand around the reef as well as the beaches of certain areas. They can produce up to one ton of sand per acre of reef (Parrotfish | Animals | Monterey Bay Aquarium, n.d.)​!

  4. These beautiful fish come in many different varieties of colors and sizes, but all play an important role in keeping algae under control on the reef, which can smother corals Parrotfish | Animals | Monterey Bay Aquarium, n.d.)​!

  • Hawksbill Sea Turtles

  1. The Hawksbill sea turtle is a species of turtle that lives on reefs all around the world and they help to open new areas of the reef up to coral growth. This is because the Hawksbill sea turtle likes to eat an interesting food item, sponges (Witherington & Witherington, 2015)!  

  2. Hawksbill turtles have pointed beaks made just for reaching into crevices to pull up sponges. The sponges, if not kept under control by the turtles, can overgrow coral (Witherington & Witherington, 2015).

  3. Did you know that the hawksbill sea turtle is a critically endangered species? It is because they are killed and collected to use their shells to make pretty jewelry often known as tortoiseshell (Witherington & Witherington, 2015).

  4. Since the Hawksbill sea Turtle is considered an endangered species, it means that anyone in possession of turtle meat or products can be punished under the law (Witherington & Witherington, 2015). 

  • Crown of Thorns Starfish

  1. The Crown of Thorns starfish is exactly what it sounds like. This species of starfish is covered in sharp poisonous spikes that cover the entire top of the starfish (Crown-of-Thorns Starfish - Oceana, n.d.).

  2. These starfish are a big concern on Australian reefs because they eat corals. Starfish will invert their stomachs out of their body through their mouth, begin to digest the soft coral polyps, and suck up the available nutrients (Crown-of-Thorns Starfish - Oceana, n.d.).

  3. If there are no predators of the crown of thorns starfish, like the giant triton, the population will get much bigger and be a threat to corals and the entire reef system (Crown-of-Thorns Starfish - Oceana, n.d.).

  4. Currently, scientists and researchers have come up with some solutions to stop outbreaks of crown of thorns starfish, which include shooting poison into the animal that is only toxic to the starfish or removal from the reef (Crown-of-Thorns Starfish - Oceana, n.d.). 

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  • Zooxanthellae Algae

  1. Zooxanthellae (zow·uh·zan·theh·lai) algae is an organism that is not an animal. It is a plant. Algae often serve as the food source for many of the reef's organisms, but certain algae live inside of corals (Zooxanthellae: Corals Tutorial, n.d.)!

  2. The algae that live inside the corals are in a symbiotic relationship with the corals themselves. Similar to how the clown fish lives in an anemone. The algae can make sugars from photosynthesis, which the corals then feed on. The waste from the coral polyps is used by the algae to begin their process of producing sugar and the cycle continues over and over again (Zooxanthellae: Corals Tutorial, n.d.)!

  3. However, if temperatures near coral reefs get too high, corals will eject their algae and will lose their color. This is called a coral bleaching event. If the temperatures don't go down, the corals will die because their food source is no longer feeding them (Zooxanthellae: Corals Tutorial, n.d.).

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References

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Quote

Jacques Yves Cousteau

"People protect what they love."

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