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Long lives and deep roots: 
Ecophysiology of cold seep vestimentiferans
(unraveled with the help of submersibles, assorted toys, and persistence)

Charles R. Fisher, Ph.D.
Pennsylvania State University

Tuesday, November 20, 2001
12:00 Noon–Pacific Forum


Vestimentiferan tubeworms were first discovered associated with hydrothermal vents, and the species found on most mid-ocean ridges are adapted to the energy-rich but ephemeral vent environment. The tubeworms found around cold seeps in the Gulf of Mexico are similar to their vent relatives in that they have no mouth, gut or anus and also rely on their chemoautotrophic bacterial symbionts for nutrition. However, using a variety of custom "toys" (such as bushmasters, banders, stainers, and deep probes), we have found that the most abundant cold seep vestimentiferan species, Lamellibrachia cf luymesi, has a very different physiological ecology and life history than its vent relatives. Individuals of Lamellibrachia cf luymesi live in excess of 170–250 years and the co-occurring Escarpid-like species lives at least as long. Sulfide is generally undetectable (<0.1mmol) around the plumes (gill-like gas exchange organs) of the seep tubeworms. On the other hand, sulfide is consistently present in substantial quantities in the interstitial waters around the buried posterior ends of the tubeworms. Their posterior ends are permeable to sulfide and we have recently demonstrated that at least one species, Lamellibrachia cf luymesi can take up sulfide across the roots at rates sufficient to fuel net inorganic carbon uptake by the worm. This adaptation provides the tubeworms access to a much more stable and longer lasting source of sulfide and provides the explanation for the growth and abundance of tubeworms in areas where sulfide is not detectable in the water above the sediments. It also has significant evolutionary implications for their life history and for the structure of the associated faunal communities.

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