Tassie_Rohan
Contributor
A recent study has shown that a deep water black coral (Leiopathes) collected off Hawaii was 4265 years old, while a golden coral (Geraridia) collected from the same area was 2742 years old. That makes the black coral the same age as the pyramids!
Biologists previously assumed that the rings in the stem of deep sea black coral were annual growth rings, like those of a tree. This lead to age estimates of a few hundred years for individual corals.
The new study used a very narrow laser beam to vaporise and test tiny sample sites from the outer to innermost growth rings, using radiocarbon dating. This revealed that deep sea black corals grow only 4 to 34 micrometers a year (that's 1/1000ths of a mm) or, for you imperial types, 0.00000002th of a mile per annum
The study was also able to detect radioactive 'bomb carbon' released by atmospheric atomic tests in the 1950's: this carbon was limited to the outmost 1/100th of a mm of the coral: indicating it took 50 years to grow that tiny amount.
The extremely slow rates of growth have big implications for conservation as black corals are currently being harvested for jewellery and damaged by deep sea fishing.
It also makes you think twice before smashing into the shallow water equivalents....
The study was published last week in PNAS: "Extreme longevity in proteinaceous deep-sea corals. Proceedings National Academy of Sciences, March 31, 2009 vol. 106 no. 13 pp5204-5208", and there was an article in New Scientist, 28 March 2009.
Cheers,
Rohan.
Biologists previously assumed that the rings in the stem of deep sea black coral were annual growth rings, like those of a tree. This lead to age estimates of a few hundred years for individual corals.
The new study used a very narrow laser beam to vaporise and test tiny sample sites from the outer to innermost growth rings, using radiocarbon dating. This revealed that deep sea black corals grow only 4 to 34 micrometers a year (that's 1/1000ths of a mm) or, for you imperial types, 0.00000002th of a mile per annum
The study was also able to detect radioactive 'bomb carbon' released by atmospheric atomic tests in the 1950's: this carbon was limited to the outmost 1/100th of a mm of the coral: indicating it took 50 years to grow that tiny amount.
The extremely slow rates of growth have big implications for conservation as black corals are currently being harvested for jewellery and damaged by deep sea fishing.
It also makes you think twice before smashing into the shallow water equivalents....
The study was published last week in PNAS: "Extreme longevity in proteinaceous deep-sea corals. Proceedings National Academy of Sciences, March 31, 2009 vol. 106 no. 13 pp5204-5208", and there was an article in New Scientist, 28 March 2009.
Cheers,
Rohan.