Nature’s great architects
From a biological point of view, coral reefs are structures built by living organisms that modify the physical and ecological characteristics of the environment in which they develop. Although they may look like plants or rocks, corals are invertebrate animals that live in colonies.
These formations act as true natural barriers, similar to breakwaters, generating areas of strong swell and others that are calmer. Thanks to this function, reefs create diverse habitats that favor an enormous richness of marine life.
One of the planet’s most productive ecosystems
Coral reefs are among the most productive and complex ecosystems on Earth. Multiple relationships between species and ecological niches take place within them, giving rise to an extraordinary biodiversity that depends directly on the good health of these structures.
The symbiosis between corals and zooxanthellae
One of the key factors in the growth of coral reefs is the symbiosis between corals and unicellular green algae called zooxanthellae. These algae live inside the corals’ cells and, thanks to an active exchange of matter and energy, allow for more efficient growth of the reef structure.
Distribution of coral reefs around the world
Coral reefs are distributed mainly between the 30° north and 30° south parallels. There is one notable exception: the Bermuda Islands, located at the 32° north parallel, where the presence of reefs is due to the influence of the Gulf Stream, which brings warm waters to the area.
Conditions necessary for reef formation
For coral reefs to develop, a series of very specific environmental conditions must be met:
Warm, shallow waters
Corals need relatively warm waters, with temperatures above 20 °C, and shallow areas, generally down to between 60 and 80 metres.
Clean, clear waters
Another essential condition is the presence of very clean water, free of inorganic sedimentation, which usually comes from rivers. Excess sediment prevents corals from developing properly.
