Pillar Coral

Fascinating facts about the Pillar Coral

• Pillar coral is one of only a handful of coral species that keeps its feeding tentacles extended during daylight hours — a strategy that dramatically increases zooplankton capture but also increases exposure to physical damage and predation. Each tentacle is armed with nematocysts, microscopic stinging cells that can immobilise tiny crustaceans and fish larvae. A fully extended pillar coral colony looks like a living fur coat rippling in the current.
• The pillars themselves are built over centuries by upward calcification, each generation of polyps depositing a thin layer of limestone atop the last. The internal skeleton of a large pillar coral is a record of every year of its life — density bands laid down in warm seasons and cool seasons create annual rings not unlike those of a tree. The oldest pillar corals are estimated to be 300–400 years old, meaning some living today were growing before the American Revolution.
• Stony coral tissue loss disease, first identified off Miami in 2014, has been catastrophic for pillar coral. The disease causes white lesions that consume tissue faster than the coral can regenerate — a colony that takes centuries to grow can be killed in weeks. SCTLD has now spread across the entire Caribbean and has been described by coral biologists as the most lethal coral disease event ever recorded. Pillar coral, with its exposed, always-extended polyps, appears especially vulnerable.
• Florida's coral reef tract is the only barrier reef in the continental United States, and pillar coral was once one of its signature species. A state-run rescue programme has collected fragments of the most disease-resistant pillar coral genotypes and is growing them in land-based nurseries — effectively a coral gene bank. The goal is to replant disease-resistant lineages once SCTLD is better understood, a strategy borrowed from tree conservation in fire-prone forests.
• Unlike most Caribbean corals, pillar coral colonies are either male or female — not both. Reproduction occurs once a year through broadcast spawning, with male and female colonies releasing gametes simultaneously into the water column on the same warm summer night. Because pillar coral is now so rare and scattered, individual colonies are often too far apart for successful fertilisation — a problem known as the Allee effect, where population collapse accelerates as density falls below a critical threshold.

At a glance

About the Pillar Coral

Pillar coral is one of the most architecturally striking corals in the Caribbean. Its thick, cylindrical columns rise vertically from the reef like stone pillars, covered with a dense carpet of extended polyps even during the day. This distinctive feeding behaviour sets it apart from virtually all other reef corals, which typically retract their tentacles in daylight and feed only at night.

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