Coral reefs are fascinating colonies that are made up of thousands and thousands of tiny individual corals known as polyps. These invertebrate marine animals have a hard exoskeleton made of calcium carbonate and are beautiful to observe. But how do these animals reproduce?
Coral reefs can reproduce both sexually and asexually. Coral reefs reproduce through a process known as budding or fragmentation. New polyps bud off from parent polyps to form new colonies. Alternatively, Coral spawning is an event in which millions of eggs and sperm bundles are released into the water once a year.
If you’re curious as to how coral reefs reproduce, then read on! We have everything you need to know about how corals reproduce.
Does Coral Reproduce Sexually Or Asexually?
Corals can reproduce in both an asexual and asexual manner, and an individual polyp may utilize both methods during its lifetime. Many species of coral are hermaphrodites as they have both female and male reproductive organs; thus, they can produce both eggs and sperm.
Corals can reproduce through either external or internal fertilization of an egg by sperm.
Internally fertilized eggs are broadened by the coral polyp for days and sometimes weeks. Larvae are then released into the water and begin to settle within a few hours.
Eggs that are externally fertilized will develop while they are adrift after multiple days. These externally fertilized eggs develop into free-swimming larvae and again settle within a few days.
Specific coral species have female and male reproductive cells, whereas others are primarily male or female.
Synchronized reproduction, known as spawning, is very prominent amongst coral colonies around the world. This method disperses eggs over a large area and is most successful when there are few low and high tides variants.
Coral reefs are also known to reproduce asexually, usually occurring when disturbances in their environmental surroundings dislodge some polyps or select parts of the colony, and they find themselves on another part of the reef.
A polyp produced via sexual reproduction can initiate the growth of a colony asexually by budding. The budding process occurs when part of the parent polyp breaks off to form a new individual.
Budding means that the polyp or individual coral can replicate itself several times and maintain its connection to the overall colony. Later this same polyp may reproduce sexually.
Coral Eggs And Sperm
Regarding sexual reproduction, multiple coral species, such as the Star coral and Brain coral, produce eggs and sperm simultaneously. Whereas, in other colonies of coral, such as the Boulder and Elkhorn species, all of the polyps within a single colony produce only sperm, whereas other colonies only produce eggs.
How Often Do Corals Reproduce?
Once a coral reef reaches a specific size or age, its cycle of sexual reproduction begins, and it will usually reproduce around once a year in order to conquer new reefs. However, it has been observed that corals can breed twice a year, and some species of coral reproduce year-round in rare cases.
Coral reefs can reproduce in great numbers due to a process known as spawning. This occurs when multiple different coral species synchronize the release of their sperm and eggs. This process has been observed on coral reefs around the world, and while it still boggles scientists as to why it happens, it is a beautiful sight to see.
How Fast Do Corals Reproduce?
Once a coral larva has been released into the open water, it will usually settle in around two days, although some have been observed to swim for up to three weeks and, in one extreme case, two months.
Corals reproduce on a massive and rapid scale once a year due to an event known as spawning. Large amounts of coral polyps simultaneously release tiny eggs and sperm bundles from their gut cavity into the open water. This allows the coral to lay millions of eggs at a specific time of the year, usually after a full moon.
If the conditions are suitable for growth, corals can grow up to 2 centimeters per year for massive corals and up to 10 centimeters for branching corals. A coral reef can take up to 10,000 years to form from a group of coral larvae.
Depending on the size of a barrier reef, this colony of coral can take anywhere from 100,000 to 300,000 years to reach its full size. This is why scientists are so worried about the state of coral and barrier reefs because they have been thousands of years in the making.
How Do Soft Corals Reproduce?
Soft corals belong to the same invertebrate family shared by snails, shrimps, and starfish. They generally have an appearance that is much fleshier and softer in comparison to stoney or hard corals.
Soft corals can grow rapidly in the right environment and under certain conditions. They don’t need to lay down stoney feet; thus, most of their energy forms branches that extend outwards and upwards.
Soft corals extend themselves out into the open water, often causing the new growth to sever from the mother colony. The disconnected polyp quickly forms into a new animal and thus spreads out even further.
Some soft corals, such as the Pulsing Xenia, can grow quite rapidly and extend out as much as 1 inch per month; however, for most soft corals, it is much less than this.
What Triggers Coral Spawning?
Coral spawning is an event that takes place once a year if corals are thriving in their natural habitat. It’s a massive event in which coral simultaneously reproduces as coral polyps release millions of tiny eggs and sperm bundles into the water.
While it’s not fully understood by scientists as to what causes this massive reproductive cycle, it’s thought that an interaction between the sun’s intensity, the phase of the moon, and the sea triggers this synchronized process known as spawning.
This synchronicity is crucial as the majority of gametes of many coral species are only visible for a few hours; thus, this massive release of eggs and sperm bundles makes it much more likely that fertilization will occur.