GoM Lamellibrachia

[Stephane Hourdez]

Dear Geoff,

	I do not agree with you on the 20-year-old estimate. The growth of 
these worms is not linear : younger worms grow over 10 cm per year but 
the bigger ones grow only less than a cm per year. It is based on this 
non-linear relationship that the lowest estimate of 80 years was obtained. 
As for the upper estimate, one cannot say. Indeed some worms did not 
grow, most of them grew very little. It seems that these guys grow by 
"burst", keeping the same length for a year (or more) and then growing 
(a few rings) in a short time. The worms which did not grow were alive 
when collected but could have been dying too. 	This is a very serious 
work, statistically robust. I think we can rely on the 250-year-old estimate 
for the age of a 2-m long worm. One can only dream about the age of the 
bigger ones.   

	So congrats guys, this was a hard and long work (have you looked 
at the number of points necessary to do these calculations.  

Bergquist, Derk C. , Frederick M.  Williams, & Charles R. Fisher. 2000. 
Longevity record for deep-sea invertebrate. The growth rate of a marine 
tubeworm is tailored to different environments. -- Nature, 403(6769):499-
500. 


Wormly yours,		Stephane


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