‘The Sun Coral’
The feeding of a Tubastrea coccinea coral cluster
Music, Video, and Aquarium
2010 Coral Morphologic

This week’s video features a colony of Tubastrea coccinea coral polyp clones feeding on passing zooplankton. The film is sped up 10 times to emphasize the feeding abilities and coordination between the sticky tentacles and the polyps’ mouths.

Tubastrea coccinea or ‘Sun Corals’, have an unusual background story, being the only invasive stony coral to become established in the Caribbean basin. Native to the tropical Indo-Pacific Oceans, they were first noted living on ships’ hulls in Puerto Rico and Curacao (Southern Caribbean) in the mid 1940’s. Over the ensuing decades, they eventually spread elsewhere throughout the entire Caribbean and Gulf of Mexico on the prevailing water currents. It is believed that these sun corals may have originally entered our region as larval stow-aways in the ballast water of intercontinental ships that passed through the Panama Canal.

Ballast water is one of the most common means by which exotic/ invasive aquatic organisms are introduced to new waters. The ecosystems of the Great Lakes have been deleteriously altered by many of these stow-aways such as the zebra mussel and lamprey. Since sun corals are common along the tropical Eastern Pacific coastlines of Central and South America, it makes logical sense that their free-floating larvae could be easily transferred over the 48 miles (77km) of the Panama Canal in the safe confines of a ship’s hull. In fact, we find it surprising that there haven’t been more species that have managed to make the crossing and establish themselves on the other side of the Isthmus of Panama.

Most stony corals rely upon energy created by photosynthetic algae (zooxanthellae) that live in their tissues. However, sun corals are different in that they lack zooxanthellae, and are not dependent upon sunlight for their survival. The energy needs of these corals are entirely met by capturing passing plankton which is most readily abundant on coral reefs at night. As such, sun corals are happy living in environments that are not suitable for photosynthetic coral species, such as caves and under-hangs. In the Caribbean, sun corals tend to be early colonizers of artificial habitats such as deep shipwrecks, oil rigs, and dock pilings; niches that are less appreciated by our native corals. For this reason, scientists have not labeled sun corals as a detrimental invasive species.

This particular sun coral colony featured in the video comes from an oil rig off the coast of Louisiana in the Gulf of Mexico. Commercial divers are regularly employed to scrape off the organisms that encrust these structures; especially when they are decommissioned. Unfortunately for this marine life, it means falling hundreds of meters into the abyss with no chance of survival. We were fortunate enough to be given a few of these otherwise doomed colonies by a researcher permitted to collect them.

Tags: Coral Morphologic, Morphologic Studios, Tubastrea coccinea

This entry was posted on Monday, February 15th, 2010 at 12:32 pm and is filed under Natural History. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.