Deep-sea coral may be oldest living marine organisms


Deep-sea coral off the coast of Hawaii may be the oldest living marine organisms, according to a study published in a recent issue of the Proceedings of the National Academy of Sciences.

Brendan Roark and coauthors applied radiocarbon dating on two groups of deep-water proteinaceous corals (Gerardia sp. and Leiopathes sp.) and found individual colonies to be as old as thousands of years.

The authors collected the coral using submersibles at depths of 400"500 m from Makapuu and Lanikai deep-sea coral beds off the coast of Oahu, Keahole Point deep-sea coral bed off the coast of the Big Island and the Cross Seamount.

According to their results, the authors found the longest-lived Gerardia sp. and Leiopathes sp. specimens to be 2,742 years and 4,265 years, respectively.

It is possible that the age of the Gerardia corals sampled may be even older, since the authors sampled only the branches and not the oldest portions of the colony.

Hawaiian deep-sea corals are threatened by being harvested for jewelry and from commercial fishing, as by-catch from trawling and entanglement and damage associated with lines and gear.

According to the authors, he extreme longevity of Gerardia and Leiopathes challenges the concept that these species are renewable in the context of fisheries management. In addition, damage to these coral species has far-reaching implications for biodiversity, ecosystem structure, and functional extinctions in the deep sea.

For more information, see the paper: Roark, EB, TP Guilderson, RB Dunbar, SJ Fallon and DA Mucciarone (2009) Extreme longevity in proteinaceous deep-sea corals. Proceedings of the National Academy of Sciences 106, pp. 5204"5208.