Coral reefs create some of the most interesting marine habitats on earth, contributing to a rich biodiversity as well as a home to many species of plants and animals. But corals must reproduce in order to keep the colonies growing, so here are the main types of coral reef reproduction that you may not know about.
Coral reefs reproduce both asexually and sexually. There are two different types of reproduction for each category, namely budding and fragmentation for asexual reproduction and broadcast spawning and brooding for sexual reproduction.
Coral reefs can reproduce asexually by budding. In this type of reproduction the polyps of a colony divide once they have reached maturity and create buds that expand the colony. The buds or resulting polyps are genetically identical to their parents.
Another type of asexual reproduction is done by fragmentation. Strong wave action or boat grounding can break fragments of colonies that are released into the water column. These are carried away by waves and currents and once they have reached a hard substrate they can reattach on they create a new colony. The new colony will be genetically identical to the parent colony.
Coral reefs can also reproduce sexually. This type of reproduction contributes to an increase in the gene pool of the species.
Three quarters of stony corals reproduce via broadcast spawning. When polyps reach sexual maturity they release male and female gametes into the water column. These are positively buoyant and they float towards the surface. In the meantime, they join and form larvae that are free floating which are called planulae. The planulae then float and the ones reaching a hard substrate will settle and create a new colony that is genetically different than the parent colony. However, due to the many hazards that can kill planulae such as predators, strong wave action or others, coral polyps release a large number of sperm and eggs into the water in order to ensure that at least a few reach maturity and settle to create a new colony.
The remaining quarter of stony corals reproduce by brooding. In this type of reproduction only male gametes are released into the water. These sperm cells are negatively buoyant, so they tend to sink to the bottom of the ocean. Female polyps then bring sperm cells inside, where the egg is, and then keep the resulting larvae until they reach maturity, releasing them shortly before they settle in the nearby area.
So here are the main types of coral reef reproduction. Learn about them and understand the needs of coral reefs, so as to protect them for future generations.