Very deep cold water coral reef found off the Greenland coast
Lophelia (commonly called eye-coral), like that seen in the depths of the Gulf of Mexico, was found by a Canadian research vessel on the Southern tip of Greenland. The colony was discovered when equipment from the vessel was tangled in the colony at approximately 3000 feet of depth.
Natural History of Lophelia
Scientific expeditions have demonstrated significant variation in Lophelia colony sizes, the largest single colony known is the Sula Reef which is in 1000 feet of water near Norway. It is 8 miles long, about 1300 feet wide and as much as 115 feet high in places. The largest known complex of Lophelia is 1200 feet deep, covering an area approximately 25 miles long by 1.8 miles wide. Most of these complexes are hard substrates on slopes, ridges, banks, seamounts and similar thresholds where currents are strong and bring in plenty of particulate food which is necessary as the coral is not photosynthetic.
Lophelia reproduces both asexually and sexually. The budding in these corals is well described in the literature, but sexual reproduction is poorly understood. The coral's growth rate is around 1 cm per year. With such a slow growth rate, imagine the damage done by physical impacts to a colony. The living corals seem to have few predators.
Lophelia in Cold Waters and the Reef
Lophelia has been reported in waters around Greenland, but everything that had been evaluated had been fragments of other corals or old worn skeletons from stylasterids, except for photographs of a reef around a half mile underwater off the southwest coast. This reef is on a rocky substrate where hexactinellids, demosponges, and octocorals also occur. The temperature was measured near 41 °F.
The Surrounding Reef
The reef itself offers numerous species the ability to find useful habitats and likely contains high diversity as with other deep water habitats discovered recently. The top 4-8 inches of the reef mass is occupied by living coral. As with tropical reefs the mass of the reef is a framework of dead coral skeletons combined with living and dead skeletal structures from other kinds of sea life. A full taxonomic analysis of the reef inhabitants identified several hundred species that represent nearly all expected temperate reef phyla.
The Importance of the Discovery
This discovery and description of live Lophelia pertusa in these waters is important to develop an understanding of the relationship between the eastern and western Atlantic distribution areas for this coral. This discovery can also be used in the future to determine the age of the reef including potential geographical origins.
Original publication: http://ices.dk/sites/pub/Publication%20Reports/ICES%20Insight/Insight%20Issue%2050.pdf (page 14-17)