Fire coral | |
---|---|
Millepora dichotoma | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Cnidaria |
Class: | Hydrozoa |
Order: | Anthoathecata |
Suborder: | Capitata |
Family: | Milleporidae Fleming, 1828 |
Genus: | Millepora Linnaeus, 1758 |
Diversity | |
15 species | |
Fire coral range | |
Synonyms | |
(Family)
(Genus)
|
Fire corals (Millepora) are a genus of colonial marine organisms that exhibit physical characteristics similar to that of coral. The name coral is somewhat misleading, as fire corals are not true corals but are instead more closely related to Hydra and other hydrozoans, making them hydrocorals. They make up the only genus in the monotypic family Milleporidae.
While most fire corals are yellow or orange, they can also be found in shades of brown, green, and even blue, providing a vibrant display underwater. [1]
Fire coral has several common growth forms; these include branching, plate, and encrusting. Branching fire coral adopts a calcareous structure which branches off into rounded, finger-like tips. Plate-growing fire coral forms a shape similar to that of fellow cnidarian lettuce corals - erect, thin sheets, which group together to form a colony. In encrusting fire coral, growth takes place on the surface structure of calcareous coral or gorgonian structures. [2]
The gonophores in the family Milleporidae arise from the coenosarc (the hollow living tubes of the upright branching individuals of a colony), within chambers embedded entirely in the coenosteum (the calcareous mass forming the skeleton of a compound coral).
Reproduction in fire corals is more complex than in other reef-building corals. The polyp of fire coral releases a medusa that releases its eggs in the water stream. Then another male medusa fertilizes the eggs with its sperm, which then produces a planula. [3] A planula then floats in the water under it finds a reef it is able to attach to and grow back into a polyp, settling on a hard surface. Then the cycle repeats. [4]
Fire corals are found on reefs in tropical and subtropical waters, such as the Indian Ocean, Pacific Ocean, and Atlantic Ocean and the Caribbean Sea. [5] [6] They are found in shallow reefs where the most amount of sunlight is able to reach them, allowing for a higher rate of photosynthesis of the algae that lives in their tissues. Fire corals thrive in an environment with a high, strong current, and warm water. [3] They are found in almost all places in the world, except for cold coastal regions. They are also abundant on upper reef slopes and in lagoons, and occur down to 40 meters (131 ft) deep.
Fire corals' predatory threats are mainly from fire worms, certain nudibranchs, and filefish. [7] They are predators to the algae that lives within them, and zooplankton/phytoplankton. [3]
The polyps of fire corals are near microscopic size and are mostly embedded in the skeleton and connected by a network of minute canals. [8] All that is visible on the smooth surface are pores of two sizes: gastropores and dactylopores. In fact, Millepora means ‘thousand pores’. Dactylozooids have long fine hairs that protrude from the skeleton. The hairs possess clusters of stinging cells and capture prey, which is then engulfed by gastrozooids, or feeding polyps, situated within the gastropores. As well as capturing prey, fire corals gain nutrients via their special symbiotic relationship with algae known as zooxanthellae. The zooxanthellae live inside the tissues of the coral, and provide the coral with food, which they produce through photosynthesis, so require sunlight. In return, the coral provides the algae with protection and access to sunlight. The hollow tubes in fire coral can also be used to store oxygen to offset any organism that bumps into it. [3]
Upon contact, an intense pain can be felt, lasting from two days to two weeks. Occasional relapses of post-treatment inflammation are common. Prominent side effects can include skin irritation, stinging or burning pain, erythema (skin redness), fever, and/or urticarian (hives) lesions. These side effects are due to venom released from the nematocyte, as venom is part of the defense mechanism of the fire coral. Despite its mild to moderate potential for pain, the venom is nonlethal to humans. The very small nematocysts on fire corals contain tentacles, protruding from numerous surface pores (similar to jellyfish stingers). In addition, fire corals have a sharp, calcified external skeleton that can scrape the skin.
The following treatments are suggestions; always seek a medical professional first.
Again, these are just suggestions; always seek a medical professional first. [8]
Fire corals face the many threats impacting coral reefs globally, including poor land management practices releasing more sediment, nutrients, and pollutants into the oceans and stressing the fragile reef ecosystem. Overfishing has ‘knock-on’ effects that result in the increase of macroalgae that can outcompete and smother corals, and fishing using destructive methods physically devastates the reef. A further potential threat is the increase of coral bleaching events, as a result of global climate change. [9]
Coral bleaching is also a major threat to all types of coral. Coral bleaching is when the coral expels the zooxanthella that they feed on, which causes them to turn white, hence "bleaching." Corals can not live long in this state, yet if environmental conditions return to normal, then the zooxanthella can return and the coral will return healthy again. [4]
Most fire coral species have brittle skeletons that can easily be broken, for example, during storms, or by divers when diving for leisure, or when collecting fish for the aquarium trade. For instance, the yellowtail damselfish ( Chrysiptera parasema ) tends to dwell close to the branching fire coral colonies, and retreats into its branches when threatened. In Brazil, fire coral colonies are extensively damaged when harvesting the yellowtail damselfish, as the corals are often deliberately smashed and fishes hiding amongst the branches are ‘shaken out’ into plastic bags. [10]
Fire corals are listed on Appendix II of the Convention on International Trade in Endangered Species (CITES). [11]
Sixteen species of Millepora are currently recognised: [12]
Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus Symbiodinium, but some are known from the genus Amphidinium, and other taxa, as yet unidentified, may have similar endosymbiont affinities. The true Zooxanthella K.brandt is a mutualist of the radiolarian Collozoum inerme and systematically placed in Peridiniales. Another group of unicellular eukaryotes that partake in similar endosymbiotic relationships in both marine and freshwater habitats are green algae zoochlorellae.
The staghorn coral is a branching, stony coral, within the Order Scleractinia. It is characterized by thick, upright branches which can grow in excess of 2 meters in height and resemble the antlers of a stag, hence the name, Staghorn. It grows within various areas of a reef but is most commonly found within shallow fore and back reefs, as well as patch reefs, where water depths rarely exceed 20 meters. Staghorn corals can exhibit very fast growth, adding up to 5 cm in new skeleton for every 1 cm of existing skeleton each year, making them one of the fastest growing fringe coral species in the Western Atlantic. Due to this fast growth, Acropora cervicornis, serve as one of the most important reef building corals, functioning as marine nurseries for juvenile fish, buffer zones for erosion and storms, and center points of biodiversity in the Western Atlantic.
Millepora dichotoma, the net fire coral, is a species of hydrozoan, consisting of a colony of polyps with a calcareous skeleton.
Porites astreoides, commonly known as mustard hill coral or yellow porites, is a colonial species of stony coral in the family Poritidae.
Pavona duerdeni, the porkchop coral, is a coral that forms clusters of cream-colored lobes or discs. They grow in large colonies, divided into ridges or hillocks. The coral is considered to be uncommon due to its low confirmed abundance, yet they are more commonly found in Hawaii, the Indo-Pacific, and the Tropical Eastern Pacific. They make up some of the largest colonies of corals, and have a slow growth rate, as indicated by their dense skeletons. Their smooth appearance is due to their small corallites growing on their surface.
Coral aquaculture, also known as coral farming or coral gardening, is the cultivation of corals for commercial purposes or coral reef restoration. Aquaculture is showing promise as a tool for restoring coral reefs, which are dying off around the world. The process protects young corals while they are most at risk of dying. Small corals are propagated in nurseries and then replanted on the reef.
Galaxea fascicularis is a species of colonial stony coral in the family Euphylliidae, commonly known as Octopus coral, Fluorescence grass coral, and Galaxy coral among various vernacular names.
Porites lobata, known by the common name lobe coral, is a species of stony coral in the family Poritidae. It is found growing on coral reefs in tropical parts of the Indian and Pacific Oceans.
Millepora alcicornis, or sea ginger, is a species of colonial fire coral with a calcareous skeleton. It is found on shallow water coral reefs in the tropical west Atlantic Ocean. It shows a variety of different morphologies depending on its location. It feeds on plankton and derives part of its energy requirements from microalgae found within its tissues. It is an important member of the reef building community and subject to the same threats as other corals. It can cause painful stings to unwary divers.
Milleporasquarrosa is a species of fire coral that can be found in the Caribbean Sea as well as in the western Atlantic. They are very common on fringing reefs in patches. They have a smooth surface covered in tiny pores from which polyps protrude. They can reach up to 5 centimeters in height and can range from brown or tan in color with slight purple or red tints. It is commonly known as "box fire coral", which refers to its box-like structure and the stinging sensation felt when touched with a bare hand. These corals are important to reef-building.
Millepora platyphylla is a species of fire coral, a type of hydrocoral, in the family Milleporidae. It is also known by the common names blade fire coral and plate fire coral. It forms a calcium carbonate skeleton and has toxic, defensive polyps that sting. It obtains nutrients by consuming plankton and via symbiosis with photosynthetic algae. The species is found from the Red Sea and East Africa to northern Australia and French Polynesia. It plays an important role in reef-building in the Indo-Pacific region. Depending on its environment, it can have a variety of different forms and structures.
Cynarina lacrymalis is a species of stony coral in the family Lobophylliidae. It is variously known as the flat cup coral, solitary cup coral, button coral, doughnut coral, or cat's eye coral. It is found in the western Indo-Pacific Ocean and is sometimes kept in reef aquaria.
Pocillopora verrucosa, commonly known as cauliflower coral, rasp coral, or knob-horned coral, is a species of stony coral in the family Pocilloporidae. It is native to tropical and subtropical parts of the Indian and Pacific Oceans.
Dipsastraea speciosa is a species of colonial stony coral in the family Merulinidae. It is found in tropical waters of the Indian and Pacific oceans.
Millepora complanata, commonly known as blade fire coral, is a species of fire coral in the family Milleporidae. It is found in shallow waters in the Caribbean Sea where it is a common species. The International Union for Conservation of Nature has assessed its conservation status as being critically endangered.
Millepora tenera is a species of fire coral in the family Milleporidae. It is native to the Red Sea and the western Indo-Pacific region and is a zooxanthellate species with a calcareous skeleton. It was first described in 1949 by the Dutch zoologist Hilbrand Boschma.
Porites cylindrica, commonly known as Hump coral, is a stony coral belonging to the subclass Hexacorallia in the class Anthozoa. Hexacorallia differ from other subclasses in that they have six or fewer axes of symmetry. Members of this class possess colonial polyps which can be reef-building, secreting a calcium carbonate skeleton. They are dominant in both inshore reefs and midshelf reefs.
Euphylliidae are known as a family of polyped stony corals under the order Scleractinia.
A corallivore is an animal that feeds on coral. Corallivores are an important group of reef organism because they can influence coral abundance, distribution, and community structure. Corallivores feed on coral using a variety of unique adaptations and strategies. Known corallivores include certain mollusks, annelids, fish, crustaceans, flatworms and echinoderms. The first recorded evidence of corallivory was presented by Charles Darwin in 1842 during his voyage on HMS Beagle in which he found coral in the stomach of two Scarus parrotfish.
This article incorporates text from the ARKive fact-file "Fire coral" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL .