Indonesian Archipelago Coral Reef – Kinds & Images

Indonesia is an archipelago, thus Indonesia has large sea surface. As a country with coastal line around 3,1 millions km, Indonesia has one of the biggest sea ecosystem in the world. Sea ecosystem relies on coral reefs. Coral reefs are a group of marine biota which live symbiotically with marine plants, for example algae. This makes the forming of coral reefs on seabeds.

See also: Indonesian Cultures – Unique Facts about Indonesia

Coral reef is a living organisms on seabeds. It serves as a habitat of marine plants, marine animals, and microorganisms. Coral reefs consists of microorganisms which symbiose with micro-algae, thus they do photosynthesis just like plants. While doing photosynthesis, they excrete oxygen, which is needed by most of living organisms. To do photosynthesis, coral reefs need sun rays. That is why they only can be found until 50 m depth, where the sun rays still can reach them. Coral reef needs very long time to grow and multiply to form the beautiful shape we see today.

They are very sensitive to environmental changes, especially temperature changes and pollution. The ideal environment for coral reefs to grow is water temperature around 200C, and minimal water pollution. However, there are also coral reefs that live in the deep sea. This type of coral reefs does not form reefs of calcium, and does not need any sun rays.

Coral reefs are one of living organisms that can be found easily on the beach, especially on Indonesian beach. Coral reefs have many types. They are distinguished into 4 groups: according to their types, shapes, habitat and zoning.

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Coral reefs are divided into 2, the soft type and the hard type.

  • The soft type is the coral reef that grows along the coast line. This type of coral does not form reefs, and they flourish very well because they get enough sun rays.
  • The hard type is corals that form calcium stones on seabeds. This type of corals is very fragile to climate changes. This is the main framer of coral reef ecosystem in the sea.

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There are 4 shapes:

  • Reef: Reef is sediment of calcium stones. This sediment has a form of backs-sea which become the framer of coastal ecosystem.
  • Coral: Coral is marine biota which has a role in forming reef. Corals have segments like bamboo, which functions as water filter to obtain planktons.
  • Coral reef: Coral reef is a soft coral which does not produce calcium. Coral reefs can be found easily near the beach.
  • Reef coral: Reef coral is a marine ecosystem, which formed because of symbiotic activities between coral organisms and marine plants.

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They are divided into 4 habitats:

  • Edge Coral Reef: This type of coral reef is the most common ones around coastal area. This coral reef can grow into 40 m depth. This coral reef forms a circle toward high sea. In Indonesia, we can find this type of coral reef in Bunaken, Panaitan Island, and Nusa Dua.
  • Barrier Reef: This type is almost the same as Edge type. But this coral reef lives far away from coastal area. It can grow into 75 m depth. In Indonesia, we can find this type of coral reef in Riau Archipelago, South Sulawesi, and Banggai Archipelago in South-east Sulawesi.
  • Coral Ring: This coral reef have form of a ring. This can be found around Atlantic Ocean.
  • Flat Coral Reef: This coral reefs form islets. The coral reef started to grow from the seabeds and keep growing until forming an islet. In Indonesia, we can find this type of coral reef can be found in Seribu Archipelago (Jakarta) and Banyak Archipelago (Aceh).

See also: Indonesian Tea – Volcanoes in Indonesia

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They are divided into 2, the ones that face the wind, and the ones that back the wind.

  • Coral reef facing the wind: It is a coral reef which slopes face the high sea. They can reach 50 m depth and usually flourishing. It is also called algae embankment.
  • Coral reef backing the wind: It is usually the hard type of coral reefs. It can be found in the sea less than 50 m deep. It looks like a narrow pressed reef.


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Coral Reef in Indonesia

Coral reefs in Indonesia is one of the richest in the world. It is estimated that the total area of world’s coral reefs are 284.300 km2, and Indonesia has 18% (85.200 km2) of the area. This is due to the fact that Indonesia is the biggest maritime country in the world, with the marine area of 93.000 km2. Indonesian coral reef also has the highest biodiversity in the world, with more than 2500 species of fish, 590 species of stone corals, 2500 species of mollusks, and 1500 species of crustaceans. So far, there are more than 750 species of corals included in 75 genus found in Indonesia.

Indonesian coral reef is also included in World’s Coral Triangle area, which is the center of world’s marine biodiversity. The coral triangle includes Indonesia, Malaysia, The Phillipines, East Timor, Papua New Guinea and Solomon Islands. If we take the straight lines of coral edges from those countries, it will form a triangle. That is why this area is called World’s Coral Triangle. The 6 countries is called CT6. The total area of coral reef in the coral triangle is around 75.000 km2.

See also: Endangered Animals in Indonesia – National Library of Indonesia


Coral reef has many functions and benefits for human life, both economically and supporting tourism activities. The functions and benefits are:

  • As a habitat to live, grow, multiply and foraging for thousands of fish, animals, and marine plants which are often consumed by human.
  • As a habitat by many endangered marine species, such as giant glam and sea turtles.
  • As a natural laboratory to support studies and researches.
  • Physically, coral reef functions as coastal protector from erosion and abrasion, and protects other beach ecosystem from damage, such as seagrass and mangroves.
  • Coral reef is a high source of fish. From 132 species of fish that have economic value in Indonesia, 32 of them live in coral reefs. Many coral fish are included in export community, such as lobsters, red snappers, and coral groupers. A healthy coral reef produces 3-10 tons of fish per kilometer square per year.
  • The beauty of coral reef is very potential for marine tourism. People who live around coral reefs can take benefits by opening diving centers, restaurants, and hotels so they can increase their incomes.

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B. Organisms

Indonesia has one of the biggest coral reef ecosystem in the world. It is estimated that 300 species of coral reefs live in Indonesia. Here are the 11 most known organisms forming coral reefs in Indonesia:

1. Acropora Cervicornis

Coral Reef, plants, sea plants, It can live in 3-15 m sea depth. This coral looks like small pipes in the seabed. The colony can gather and grow into a few meters square. This coral consists of many cylindrical branches which look like tree twigs. The coralyte axis can be different from one another. It has the similarity with Acropora prolifera.

This coral is usually have light brown color, and live in clear and unpolluted water. It also can be found in upper slopes of lagoons, and in the middle of reefs. This coral can be found abundantly in Indonesia, Jamaica and Cayman Islands.

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2. Acropora Elegantula

coral reef, plants. sea plants, ocean,It lives in 3-15 sea depth. The coral looks like widened bush. The branches are thin and grow horizontally. T

he coralyte axis can be seen clearly. When struck by water current, the coral will move very softly like dancing, because of the uniformed size of the branches.

The coral has grey color, with pinkish points. It has the similarity with Acropora aculeus. This coral can be found easily in any shallow sea. The coral can be found in Indonesia and Sri Lanka.

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3. Acropoda Micropthalma

coral reef, plants. sea plants, ocean,This coral lives in 3-15 m sea depth. The coral looks like widened and depressed pipe with light-colored brances. It can form a big colony , and the colony consists of only 1 species without addition of other corals.

Moreover, it has the similarity with Acropora copiosa, Acropora parilis, and Acropora horrida. It can be found in shallow cloudy sea and sandy lagoons. We can find this coral in Indonesia, Papua, and Australia.

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4. Acropora Millepora

coral reef, plants. sea plants, ocean,It lives 3-15 m sea depth. It looks like a pad with uniformed short thick branches. It has the similarity with Acropora aspera, A.covexa and A. Pulchra; However, A.millepora has radial coralyte and fragmented coralyte axis.

This coral is colorful, with combination of green, red, blue or orange colors. It is easy to find in shallow unpolluted sea. This coral can be found in Indonesia, the Phillipines, and Australia.

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5. Acropora Humilis

coral reef, plants. sea plants, ocean,This coral lives in 1-7 m sea depth. The branches is thick, with big coralyte and has 2 sizes of radial coralyte.

On the other hand, it is also called ramified corals, as it has so many branches. It has the color of creme, brown, blue, violet or pink. It lives around flat reefs and reef slopes.

This Indonesian coral reef can be found easily in territory of archipelago, and dispersed from Red Sea to Indo-Pacific and Central America.

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6. Acropora Hyacinthus

Coral reef, ocean, plants, sea, sea plantsIt lives in 15-35 m sea depth. This is a fragile coral. The coralyte looks like a bowl, with widened edge. Due to the widened shape, it is also called “table coral”.

On the other hand, this type of Indonesian coral reef, also has the similarity with Acropora cytherea. Then, it can be found in any reef slopes or shallow water. The coral can be found in Indonesia and Australia.

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7. Sideratra Sidereal

coral reef, plants. sea plants, ocean,It lives in 7-14 m sea depth. In some places, it also can be found in 1 m sea depth. The coral consists of colony which form a big round stone.

Then, the colony can spread into a few meters wide. Some of the coral also look more depressed than usual.

Moreover, the color is uniformed, usually brown or grey. It grows in clear and unpolluted water.

This type of  the coral can be found in Indonesia and the Caribbeans.

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8. Montiphora Danae

coral reef, plants. sea plants, ocean,This coral lives in 3-15 m sea depth. It is dome shaped with small coralyte. It can form a shape of inverted plate.

Then, The color is light brown, purple, or other bright colors. It has the similarity with Montipora verrucosa and M. Palawanensis. It can grow very fast, so it is not ideal for marine aquarium. It can be found in upper slopes of reefs and clear lagoons. The coral can be found in Indonesia, Papua New Guinea, the Phillipines, Japan, and Madagascar.

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9. Montipora Aquituberculata

coral reef, plants. sea plants, ocean,The coral lives in 3-15 m sea depth. It looks like layered funnel.This coral cosists of coralyte surrounded by thick papillae. Over time, the coral will form calcium so it looks like a funnel.

Then, it has the similarity with Montipora peltiformis. The coral has brown or orange color. It can be found in shallow water with numerous corals.

Just like M.danae, it can be found in Indonesia, Papua New Guinea, the Phillipines, Japan, and Madagascar. It also can be found in Australia.

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10. Acropora Grandis

coral reef, plants. sea plants, ocean,This coral lives in 3-15 m sea depth. The deeper the water, the branch will be longer and more overt. The lower the water, the branch will be shorter.

On the other hand, this coral is colorful, can be brown, pink, blue, or green. The points has lighter color. It can be found in upper slopes of reef. This coral can be found in any tropical area.

Acropora Grandis also can be found in Indonesia, Papua New Guinea, the Phillipines, Japan, Madagascar, and Indo-Pacific.

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11. Antiphates sp (black coral)

coral reef, plants. sea plants, ocean,Antiphates is called Akar Bahar in Indonesian. It looks like a plant roots with black, red or white color, but in fact it is a coral.

Indonesian people believe that this coral has supranatural ability. The number is declining fast, since people are harvesting them in big quantity to make charmed accessories such as bracelets and smoking pipe.

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Where to Find Good Coral Reef in Indonesia

Area which still has good coral reef in Indonesia is Raja Ampat in West Papua. According to an ecological research in 2002, there are 537 species of corals and 1074 species here. This means that Raja Ampat has the biggest diversity of coral reef in the world. The amount of species in Raja Ampat coral reef is 75% of all coral species. Although the Carribeans in Central America and Great Barrier Reef Marine Park in Australia are very famous, they only have 400 species of corals.

Other archipelagos in Indonesia also have big diversity of corals. We can find good corals in Derawan Archipelago, East Kalimantan (444 coral species); Banda Island (330 species); Nusa Penida, Bali; Komodo Island, East  Nusatenggara; Bunaken, North Sulawesi; Wakatobi Archipelago, South-east Sulawesi; and Cendrawasih Bay, Papua.

See also: Indonesian Human Rights – Hinduism in Bali


What a pity that only 30% of coral reefs are still in good condition in Indonesia. From a study in 2000, it was concluded that the “very good” coral reefs are only 6,1% and the “good” one are only 22,68%. The rest are “damaged” (31,46%) and “heavily damaged” (39,76%).

Damaged Coral Reef in Indonesia

The national oceanographic research paid attention to coral reefs condition starting from Sabang (Aceh) to Padaido Archipelago (West Papua) in 1993-2007. They published the result in 2007, which said that only 5,2% is in very good condition, 24,2% in good condition, 37,2% in average condition and 33,1% in bad condition.

The damage of coral reef is often caused by human, for example fishing using poison and bombs, taking corals for building foundation, sedimentations caused by deforestation, city development, and over fishing. Moreover, the damage is also caused by global warming, which leads to increased acidity of the sea water and the raising temperature. These conditions kill the organisms forming the corals.

Recently, a big English cruise ship hit a big coral reef in Raja Ampat. This kind of accident also destroy coral reefs, especially because we do not know how many ships have hit coral reefs before.

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How to Conserve Coral Reefs

There are various ways to conserve coral reefs, for example:

1. Keeping rivers and coastal areas clean

Rivers – to – sea water flows is very important for the water cycle. Since ancient time, river has been used for transportation, for taking bath, washing clothes, and to throw away home / factory wastes. Factory wastes usually contain dangerous metal substances, like mercury. Heavy metal is very dangerous for environments so the governments should watch the waste management of each factory. All the wastes that are thrown to the rivers would later accumulate in the sea.

The same with throwing garbage to the beach. The garbage on the beach would later be washed away into the sea by the waves, and the plastic waste can destroy coral reefs. The main effect of plastic waste is inhibiting sun rays into the sea. The sun rays are needed for photosyntesis activity of the corals, and the plastic waste inhibits this process by covering the corals, so the microorganisms (zooxantellae) cannot get enough sun rays to do photosyntesis. Moreover, touching the coral can kill zooxantellae too.

2. Stopping Erosion on the Beach

Erosion is erasure of upper layer of the soil. In some numbers, erosion is normal, but human activities makes it worse. Deforestation for example, can reduce the absorbtion ability of rain water. It makes the upper layer of the soil are taken with the water flow, and it causes sedimentation in the sea.

Sedimentation inhibits coral growth by covering the coral’s pores, and the turbid water deprives the zooxanthellae of the sun rays. With minimal sun rays, the zooxanthellae will die.

3. Fishing Without Destroying Coral Reefs

Coral reefs is a good habitat for fish growth. No wonder many fishermen like to do fishing around coral reefs. Some irresponsible fishermen usually use fishing bombs to get fish easily. The bombs will destroy coral reefs in no time. Not only the big fish, but all marine biota in the coral reef will die. The destruction of coral reef would later give impact to the fishermen, as destruction of the fish’s habitat will reduce the number of fish too.

4. Not Taking Corals and Coral Reefs Away

Corals are the main attractions for people who love scuba diving. Some people like to snatch it and regrow it in their marine aquarium. But we have to remember that corals are really dependent on temperature and salinity of the water to grow. If we move the corals to a new place, most likely the corals will die because of unnatural environments. It needs socialization to keep the corals live in their natural habitat.

5. Education about Corals and Coral Reefs to Small Children

The willingness to conserve coral reefs needs to be implemented since the beginning. It is advisable to start giving ecology lessons for children, starting in kindergarten. We all know that small children absorb informations more fast and effective than adults. If the children are given the lessons about the importance of coral reefs, they will remember the lessons for the rest of their lives.

6. Socialization of Coral Reef Functions and Benefits

Just like the 5th point, we need to socialize about coral reef functions and benefits to people around coastal area. Most of traditional Indonesian fishermen have low education, so we must give them idea why it is wrong to throw garbages into the sea, and why it is wrong to use bombs in fishing. By giving them the reasons of the 2 main problems, they would comply better.



Indonesian Goverment Action to Protect Coral Reefs

Understanding that coral reefs are very important to human’s life, the 6th President of Indonesia, Susilo Bambang Yudhoyono, launched the protections of coral reefs in World’s Coral Triangle area in APEC meeting in Sydney 2007, together with 6 other coral triangle countries (CT6). The initiative of CT6 countries to protect coral triangle is called Coral Triangle Initiative (CTI). This initiative has many supports from developed countries, such as USA, Australia, and other European countries.

Following the CTI, since 2009, a new law was added to ban the use of toxins and bombs for fishing. Any fishermen who still uses toxins and bombs can be sued and jailed.

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As younger generation, we should realize that coral reef is really important. We also can educate people around the coastal area not to throw rubbish to the sea, to maintain clean and healthy water needed by the corals to grow; plus we can start doing that ourselves. If we do snorkeling or diving, we should not touch the corals or step on the corals, since it kills coral organisms.

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