Bubble Coral

Appearance

Colonies of "Plerogyra sinuosa" are in the form of an inverted cone that may be as much as a metre across. The corallites in small colonies are monocentric and trochoid, but become flabellomeandroiid in larger colonies. The septa have smooth margins but are irregularly arranged giving the colony an untidy appearance. The costae on young colonies sometimes form lobes which develop spines. These spines then elongate and a new polyp develops, this budding method being an unusual occurrence among corals.

In the living coral, "Plerogyra sinuosa" has vesicles resembling bubbles up to 2.5 cm in diameter. These enlarge during the day but retract to a certain extent during the night to expose the polyps and their tentacles.

Naming

Common names for "Plerogyra sinuosa" include "grape coral", "bladder coral", "pearl coral" and "branching bubble coral".

Status

This is a common, widely-distributed species in shallow reef environments. It is subject to the threats of climate change and destruction of its reef habitat common to other coral species, and the International Union for Conservation of Nature has assessed its conservation status as being "near threatened".

Behavior

"Plerogyra sinuosa" is a zooxanthellate species of coral. It obtains most of its nutritional needs from the symbiotic dinoflagellates that live inside its soft tissues including the walls of the vesicles. These photosynthetic organisms provide the coral with organic carbon and nitrogen, sometimes providing up to 90% of their host's energy needs for metabolism and growth. Its remaining needs are met by the planktonic organisms caught by the polyps.