Coral reefs are seabed ecosystems whose main inhabitants are rock corals. These various species and forms of rock corals form ecosystems along with other living organisms. During the lengthy process of forming coral reefs, the corals have also been inhabited by various other living things.
Coral reefs are typical ecosystems of tropical regions, with distribution centers in the Indo-Pacific region. The distribution of coral reefs in tropical waters, stretching latitudinally from southern Japan to northern Australia, is influenced by temperature and water surface circulation. Longitudinal distribution is greatly influenced by the presence of "stepping stones." The vast dispersal of coral reefs in the Indo-Pacific region is believed to be highly supported by the combination of physical environmental conditions (temperature and surface circulation) and the abundance of stepping stones found in the region. Approximately 800 coral species have been described, with 600 of those species found in Southeast Asia, primarily in Indonesia and the Philippines.
Symbiosis of Zooxanthellae with Corals
Corals (Scleractinia) are animals, although for millennia they were mistakenly thought to be rocks or plants. Corals belong to the class of polyp-shaped Coelenterata, which have a mouth at the top encircled by tentacles. These animals are morphologically similar; the variation is in the variety of skeletons they have. As a result, the structure of coral development serves as the basis for their taxonomy. Corals have the ability to be sessile, which has repercussions for their strict lifestyle when living this way.
One of the conservative properties of coral biota is the existence of a symbiotic process with zooxanthellae. The formation of this symbiosis, known as endosymbiosis, has given rise to several theories. One theory is that endosymbiosis is formed when the coral larvae (planulae) are released by their mothers. Another theory suggests that the endosymbiosis occurs through infection from planulae released without zooxanthellae. The endosymbiosis process is very important for coral life. In the early stages of evolution, it was understood that the symbiosis between zooxanthellae and corals in the marine ecosystem was an event that began with the meeting of zooxanthellae and corals. This meeting was likely because corals are sedentary and zooxanthellae are planktonic. Ultimately, the relocation of zooxanthellae onto corals is a biotic response to the dynamic physical activity of seawater and the process of chemical interconnectivity. Thus, the opportunity for these two to meet is very likely to occur at sea.
The mutuality of these two biota is evidenced by the discovery of a large number of zooxanthellae in each polyp. Zooxanthellae live in symbiosis, giving color to the polyps and providing 90% of the energy from photosynthesis for the carbon needs of the polyps. Zooxanthellae receive essential nutrients from corals (polyps) and provide as much as 95% of their photosynthetic products (energy and nutrients) to the polyps.
Symbiosis of Sea Anemones and Clownfish
Sea anemones (Stichodactyla) are animals from the phylum Cnidaria and the class Anthozoa, which at first glance look like plants. Anemone habitats are mostly found in shallow coral reef areas and are rarely found in coral reef areas with a high percentage of rock coral cover. The morphology of anemones resembles a rose. The circular folds between the body and the mouth divide this animal into two parts: the upper part called the capitulum and the lower part called the scapus. Between the neck arch (collar) and the base of the capitulum is a "fossa." The mouth parts are flat, circular, and sometimes wrinkled. Some sea anemones can move slowly by attaching like snails, and most anemones have stinging cells that are useful for protecting themselves from predators.
Clownfish are fish from the subfamily Amphiprioninae in the family Pomacentridae. There are twenty-eight commonly recognized species, one of which is the genus Premnas, while the rest belong to the genus Amphiprion. They are spread across the Pacific Ocean, the Red Sea, the Indian Ocean, and the Great Barrier Reef of Australia. Clownfish (genus Amphiprion and Premnas) are tropical reef fish that live in warm waters in reef areas with a depth of less than 50 meters and clear water. Their distribution areas include the Pacific Ocean (Fiji), the Red Sea, the Indian Ocean (Indonesia, Malaysia, Thailand, Maldives, Burma), and the Great Barrier Reef of Australia. Clownfish coexist with anemones and benefit each other in a mutualistic symbiosis.
The symbiosis between sea anemones and clownfish involves protection from sea anemones for clownfish against predators, while clownfish clean anemones of their food residues. This interaction is what gives clownfish the name "anemone fish." Research conducted by Raja Ali Haji Maritime University stated that for each specific type of anemone, there is only a certain type of clownfish. It is suspected that each type of clownfish will only form a symbiotic relationship with one specific type of anemone because there is a real relationship between the type of anemone and the type of clownfish. The presence of a specific type of anemone also affects the distribution of Amphiprioninae fish. Deakin University researcher Rohan Brooker also mentioned that the mutualism between clownfish and anemones has evolved at least 55 times in the genealogy of 16 fish families over the past 60 million years.
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