Akantaster: who will stop the coral eater and save the reefs of the planet

Ecologists blame global warming and the excessive flow of pollutants into the ocean for the disappearance of coral reefs in tropical waters. But biologists are sure that the trouble of corals is not only anthropogenic impact on the planet: an insidious predator eats corals, destroying reefs and depriving their numerous inhabitants of their homes. These are acanthasters, seemingly plain and fearless inhabitants of the seas, who cause significant damage to coral colonies around the world.

Acanthasters, or crown of thorns, belong to the class of starfish. But these are truly terrible starfish, since they have not 5, but more than 10 rays, and their sizes reach half a meter. This marine predator has a peculiar body structure, which allows it to eat the adult forms of coral - the very polyps from which the reef is built. A starfish literally turns inside out, placing the victim inside his body. Then, an active digestive enzyme is used, which can even digest coral solids. So, absorbing and corroding the polyp after the polyp, the insidious acanthaster moves along the seabed. Interestingly, predators that find coral emit specific substances that attract other starfish. Their silent victims are absolutely defenseless against insatiable enemies, each of which is capable of completely destroying a 3 by 4 meter area covered with corals in a year. Although the crown of thorns can be fed by other inhabitants of the seabed, coral polyps are their favorite food. Sometimes in symbiosis with corals live crabs that are able to drive away a small starfish and thereby save the life of their partner.

For the first time, a surge in starfish activity was noted in the 60s of the last century in the area of ​​the Great Barrier Reef and other Pacific reefs. Then scientists recorded a significant decrease in reef area, and in some areas, corals were completely destroyed. A similar picture was repeated repeatedly, but for what reason there is a sharp increase in the number of predators, and then a decline, until it was possible to find out. Perhaps this is due to an increase in the amount of organic matter in the ocean caused by sewage. Warm water and an abundance of organics cause a surge in the number of acanthasters. Scientists seriously feared that an excessive number of crown of thorns would lead to the death of the Great Barrier Reef or irreversible changes in the entire ecosystem.

By the way, these stars are dangerous not only for coral colonies, but also for other inhabitants of shallow sea water, as well as for people: their sharp needles are equipped with poison, which causes intoxication. But this insidious predator also has a weak link. When acanthasters just begin their life's journey, they are very small, unable to produce dangerous toxins and serve as food for larger reef inhabitants. But, they initially have a huge number, so a significant amount survives to adulthood. Scientists are fighting coral pests by collecting adults, as well as using chemicals. Perhaps the only one who can help scientists in their struggle to preserve coral is charonia triton. This large mollusk feeds on acanthasters, in which it helps a powerful leg and sharp teeth. But because of its large beautiful shell, the mollusk itself, alas, became a victim of predatory extermination by humans. Today, in many regions of the Indian and Pacific Oceans, its catch is prohibited, so scientists hope that with the restoration of the number of mollusks, it will be possible to stabilize the number of acanthasters.

Watch the video: What Happens If All The Coral Dies? (May 2024).