Black coral shown to take thousands, not hundreds, of years to grow...

[Tassie_Rohan]

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 1/1000^ths of a mm) or, for you imperial types, 0.00000002^th 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 1/100^th 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.

 

[shoredivr]

Wow, Tassie, that's really interesting info. As a species, humans tend to have little concept of other life forms on the planet and their longevity- other than "what can we use them for?".

That was a nice bit of "wonder" at the world we live in. Thanks.


*Edit*

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.

We assume so much it's boggling at times.

 

[Peter Guy]

shoredivr wrote

As a species, humans tend to have little concept of other life forms on the planet and their longevity- other than "what can we use them for?".

I give, what species does seem to have a "concept of other life forms on the planet and their longevity- other than 'what can we use them for?'"

 

[Tassie_Rohan]

Yep - I find it hard to comprehend just how long they live for. There's no way these corals can ever be harvested in a sustainable manner, at least in the timeframe of human civilisation.

It will be interesting to see if this research actually helps protect black coral - I somehow doubt it...

Cheers,
Rohan.

 

[smellzlikefish]

Not with corals like this being scraped off seamounts daily by draggers. Seamounts are one of the real shames of the pelagic realm. International law has no enforcement capabilities, so these ships go out of countries with liberal laws. The result is seen by ecologists who visit many by submersible. Some are covered in these thousand year old corals, while others are scraped clean. The commercial search for "Chilean Sea Bass" and orange roughy is destroying many of these habitats. BTW, Chilean Sea Bass isn't a bass at all, but a species of deep sea fish that reproduces very slowly. It just isn't marketable under its real name, Patagonian toothfish.