Pillar coral, a distinctive stony coral, is an integral part of shallow marine environments. These organisms contribute significantly to the complex architecture of coral reefs, supporting rich biodiversity. Understanding pillar coral helps illuminate the broader dynamics of these sensitive underwater ecosystems.
Unique Features and Home
Pillar coral (Dendrogyra cylindrus) is identified by its upright, finger-like or column-shaped growths. Unlike many other stony corals that form broad, flat structures or branching patterns, pillar coral columns can reach heights of up to 10 feet (3 meters) and are 4 to 12 inches (10 to 30 cm) in diameter. These columns often have blunt, rounded ends and appear in shades of brown, yellow, or greenish-brown, camouflaging them within their surroundings.
Pillar coral polyps often extend during the day, a behavior uncommon among other coral species whose polyps typically retract in daylight. This allows them to capture food particles from the water column even when sunlight is abundant. Pillar coral thrives in clear, shallow waters, found at depths ranging from 1 to 20 meters (3 to 65 feet), preferring hard, rocky substrates. Its geographic range is limited to the western Atlantic Ocean, found throughout the Caribbean Sea, the Gulf of Mexico, and along the Florida Reef Tract.
Role in the Ocean Ecosystem
Pillar coral colonies provide structural complexity to the reef environment, creating intricate three-dimensional habitats. These dense, upright columns offer sheltered spaces and hiding spots for numerous marine species, including small fish, invertebrates like crabs and shrimp, and juvenile organisms. The architecture of these corals helps increase the overall surface area of the reef, supporting a greater diversity of life.
Beyond providing shelter, pillar coral contributes to the reef’s food web and nutrient cycling. Its polyps, with their extended tentacles, filter microscopic organisms from the water, transferring energy within the ecosystem. The coral’s calcification process, where it extracts calcium carbonate from seawater to build its skeleton, also plays a role in the health and growth of the reef structure. The presence of healthy pillar coral colonies indicates a functioning reef ecosystem, which supports marine biodiversity.
Challenges and Protection Efforts
Pillar coral faces threats, primarily from global climate change, including rising ocean temperatures and ocean acidification. Elevated water temperatures cause coral bleaching, a phenomenon where corals expel symbiotic algae, leading to a loss of color and often death if conditions persist. Ocean acidification, resulting from increased absorption of atmospheric carbon dioxide, reduces the availability of carbonate ions, making it harder for corals to build and maintain their calcium carbonate skeletons.
Pollution from land-based activities further endangers pillar coral. Runoff containing sediments, nutrients, and chemical pollutants from agriculture and urban areas can reduce water quality, block sunlight, and promote the growth of harmful algae that outcompete corals. Plastic pollution also poses a direct threat, as plastics can smother corals, introduce pathogens, and cause physical damage.
In addition to environmental stressors, Stony Coral Tissue Loss Disease (SCTLD) represents a highly contagious threat, causing rapid tissue loss and mortality in pillar coral and many other stony coral species. This disease, first observed in Florida in 2014, has spread throughout the Caribbean, devastating coral populations.
To address these challenges, pillar coral received protection under the U.S. Endangered Species Act in 2014, designating it as a threatened species. This listing provides legal safeguards and promotes conservation actions. Restoration initiatives are underway, involving the collection of coral fragments to grow in offshore nurseries. Once sufficiently sized, these corals are outplanted back onto degraded reefs to help re-establish populations. Public awareness campaigns also educate people about the importance of coral reefs and promote sustainable practices to reduce human impact on these ecosystems.