Lobophyllia, also known as brain coral, lobed brain coral or lobed cactus coral, is a species of stony coral found in the Indo-Pacific region and not uncommon in the Red Sea either. These large, stony corals are especially resistant and hardy, often qualified as being disease-free, but they are also susceptible to the damages caused by climate change such as temperature hikes and changes in acidity levels.
The Lobophillia coral derives its name from its characteristic shape – it looks like a human brain, indeed, spherical and grooved. The large, brain-shaped formations are made up of tiny polyps that produce calcium carbonate, with the individual polyps that make them up being impossible to identify. The polyps align themselves in rows, the groves visible on the surface of the coral being formed by the mouths of the polyps. The colonies comprise hundreds of polyps, the largest ones even thousands, so brain corals are among the largest of all corals.
Given the special structure of their body, brain corals are very hardy and resist well to storms and aggressors, therefore they have the longest life span among corals, the largest ones can be almost a thousand years old.
Brain corals present wide diversity in terms of color – tan, orange red and purple specimens are just as common as yellow, brown and green ones. They can be uniform in coloring or multi-colored. Colonies may become multi-colored, too – in many cases, separate mounds grow together and form a composite.
Brain corals are very resistant and hardy, which allows them to thrive in various different environments. Some sub-species prefer shallow waters with low currents and form colonies in lagoon areas and on upper reef slopes, usually not deeper than 15 m, while others prefer deeper waters and thrive well even at 30 m depths.
Similarly to other corals, brain corals access nutrients via photosynthesis, with the help of the zooxanthellae algae that live in symbiosis with the brain corals, inside their labyrinth-like body. They also use their long sweeper tentacles to filter the water and to extract drifting food particles. In the case of most brain coral species, direct feeding happens during the night only, but some species, such as Favia, direct-feed during the day, too, and protect their tentacles with stinging cells.
Brain corals have two reproduction types:
asexual, by means of a process called budding, in which the adult coral produces a new polyp by dividing itself;
sexual, by spawning, process during which gametes are released into the water to be fertilized externally.
Though proliferation happens once, sometimes two times a year, brain corals grow and expand very slowly.
The threats that affect coral reefs in general affect brain corals as well. The pollution of the seas and oceans caused by the growing human population on the shore, the impact of climate change on water temperature and water composition all pose risks for coral reefs in general and for lobophyllia corals in particular.