Coral reefs are home to many organisms such as sponges, fish including large nurse sharks and reef sharks, eels, snappers, parrotfish, jellyfish, groupers, clownfish, anemones, crustaceans, other invertebrates and algae.
A symbiotic relationship is formed when two different species interact with each other. These interactions create a balance within the ecosystem because at least one of the species benefits. Other species may also benefit from the relationship, be unaffected by it, or even be harmed. the relationship.
Symbiotic relationships are widespread in the ocean, especially near coral reefs. There are three main types of symbiotic relationships: mutualism, parasitism, and commensalism. Mimicry is also found in coral reef organisms.
Types of Mutualism: There are two primary types of mutualism: obligate mutualism and facultative mutualism.
Mutualism, or a reciprocal relationship, is when two organisms of different species work together so that each benefits from the relationship.
• Obligate mutualism is the type where neither organism can live without one another. An example of obligate mutualism would be the relationship between hard coral and algae (zooxanthellae). The relationship between coral and zooxanthellae (algae), is a mutualistic relationship that is one of the most important within the coral reef ecosystem.
Zooxanthellae are microscopic photosynthetic algae that live on corals. In exchange for their protection from herbivores and other organisms, zooxanthellae photosynthesize organic compounds from the sun and then transfer the nutrients glucose, glycerol, and amino acids, which are the products of photosynthesis, to their coral hosts, essentially giving coral reefs their beautiful colors. Zooxanthellae also aid in the excretion, or removal of waste such as carbon dioxide and nitrogen.
Corral reef wouldn’t exist without algae. The coral would starve to death, this is known as coral bleaching, and if algae didn’t have protection, they would be more vulnerable to several herbivores and other organisms.
The mutualistic relationship between anemones and a clownfish is also another commonly known relationship. Clownfish are found in warmer waters of the Indian and Pacific oceans. Of the over 1,000 anemone species that live in the ocean, only 10 species coexist with the 26 species of tropical clownfish. Within these species, only select pairs of anemone and clownfish are compatible.
Sea anemones are actually predators, with stinging polyps, that attach themselves to rocks, the ocean floor, or even coral. They patiently wait for fish to swim by close enough to get entangled in their poisonous tentacles. The toxins paralyze their prey, and the tentacles guide the prey into the anemone’s mouth.
However, clownfish are the exception and actually call the anemone home. Clownfish are coated with a mucus layer that essentially makes them immune to the deadly sting of the anemone. Therefore, clownfish are able to live within the anemone’s tentacles, while also gaining protection from predators, and the clownfish helps feed the anemone by either letting them eat their leftovers, or by also luring fish over to the anemone so that the anemone can catch them with their poisonous tentacles, and eat them for dinner (or maybe lunch).
Facultative mutualism: The other type of mutualism is when species benefit from each other but are not necessarily fully interdependent. An example of facultative mutualism is the relationship between certain types of gut bacteria or the bacteria that live in our digestive tract. When we eat food, bacteria use some of the nutrients in the food we digest and in turn help us digest our food.
Again, a more specific example of facultative reciprocity that is more closely related to the coral reef ecosystem is the relationship between shrimp, smaller fish, and large marine organisms. Shrimp or cleaner fish remove materials such as parasites from larger fish. Marine organisms from which they receive a meal and larger marine organisms are removed from potentially harmful parasites.
As mentioned earlier in this post, smaller fish or cleaner shrimp like bluefish or hogfish remove parasites and other material from larger marine organisms like fish, sharks, and fish. In most cases, these smaller fish would normally be preyed upon by larger marine organisms, but in this case, these larger organisms benefit from these parasites being removed and potentially causing damage while the smaller fish or shrimp are given a meal.
The cleaner fish and the larger fish share a mutual relationship. This is because cleaner fish eat harmful parasites and other small food sources from larger fish. This gives the cleaner fish a meal, and the larger fish benefit because they no longer have these parasites.
Larger fish often wait at “cleaning stations” for cleaner fish to come and remove these things. Some small shrimp can also be cleaners. The image below shows a cleaner shrimp cleaning a large fish at a cleaning station that would normally eat the shrimp were it not for this reciprocity.
Another facultative interrelationship exists between the root rotting sponge Tedania inis and the red mangrove Rhizophora mangle. In this relationship, the red mangrove supplies the sponge with the carbon produced by the mangrove, and the nitrogen released by the sponge is the mangrove to promote growth.
Mutuality also occurs between crabs and algae. This relationship benefits both species, as the greenish-brown algae live on the spider’s back and help the spider crab blend in with the shallow areas of the seafloor where they live. In return, the algae benefit from a good habitat.
Another example is the relationship between the boxer crab and anemones. In this regard, the boxer crab carries two stinging anemones and uses them for protection. Anemones benefit from this because when the crab is carrying them, they can be mobile, increasing their foraging opportunities.
A final mutual relationship is that between a goby (Nes longus and Ctenogobius saepepallens) and a snapping shrimp (Alpheus floridanus). The shrimp digs a decent burrow on the seabed and the goby lives at the entrance of that burrow. When the shrimp exits the burrow, it stays in contact with the goby via its antennae and, depending on the goby species, signals the shrimp that predators are approaching by diving headfirst into the burrow or by wiggling its tail. Line. Ultimately, the goby gets a free space to live and hide from potential predators, while the shrimp in return gets an individual observer when foraging.
Parasitism: Parasitism is not a mutual relationship since only one of the species benefits from it. The parasite benefits from the relationship while the other species involved are harmed. Ectoparasites live outside the host’s body while endoparasites live inside the host.
An example of an ectoparasitic relationship is between fish lice and small fish hosts. The fish can die if too many lice stick to it. Lice benefit from fish by feeding on their body fluids.
Isopods can also cause them to be involved in a parasitic relationship. Some eat the tongue of fish and then live in the fish’s mouth so they can eat whatever the fish tries to eat.
Commensalism: Commensalism is a relationship in which one species benefits from another species. The other species is neither harmed nor helped in this respect. There are many examples of ocean commensalism.
An example of commensalism among marine life is jellyfish and small fish. Small fish usually hide in the stinging tentacles of jellyfish when not affected by the sting. The tentacles protect the fish from larger predators.This relationship does not affect jellyfish.
Another relationship exists between the shrimp and a feathered star. The shrimp mixes with the feather star and uses it for protection.
Mimicry: One type of mimicry is when a harmless organism evolves to resemble another poisonous organism. This prevents predators from eating them, thinking they are venomous species. They can also use mimicry to appear larger than they really are. are. The four-eyed butterflyfish uses a large eyespot to appear larger to predators.
Another example of mimicry is found between the sabretooth blenny and the cleaner fish. The cleaner fish has a mutualistic relationship with larger fish such that they will not be eaten, and the sabretooth blenny takes advantage of this relationship by evolving to become very similar to the cleaner fish. Instead of cleaning the bigger fish, the Sabretooth Blenny takes a meat nibble from the big fish and swims away. This is an example of aggressive mimicry.
Mutualistic relationships, whether obligatory or facultative mutualism, are an integral part of maintaining a coral reef ecosystem, and without them coral reefs simply would not exist. These interrelationships define a largely intricate set of connections and relationships that are highly interdependent, and where one might begin to deteriorate, another might as well.
It is more important now than ever that we sustain healthy coral reefs to support these intricate relationships, communities, and ecosystems.
Erzsebet Frey (Eli Frey) is an ecologist and online entrepreneur with a Master of Science in Ecology from the University of Belgrade. Originally from Serbia, she has lived in Sri Lanka since 2017. Eli has worked internationally in countries like Oman, Brazil, Germany, and Sri Lanka. In 2018, she expanded into SEO and blogging, completing courses from UC Davis and Edinburgh. Eli has founded multiple websites focused on biology, ecology, environmental science, sustainable and simple living, and outdoor activities. She enjoys creating nature and simple living videos on YouTube and participates in speleology, diving, and hiking.