Editing Siboglinidae (section)

===Vestimentiferan ecology===
Their primary nutrition is derived from the sulfide-rich fluids emanating from the hydrothermal vents where they live. The sulfides are metabolized by [[symbiotic]] hydrogen sulfide- or methane-oxidizing [[bacteria]] living in an internal organ, the [[trophosome]]. One gram of trophosome tissue can contain one billion bacteria. The origin of this symbiotic relationship is not currently known. The bacteria appear to colonize the host animal larvae after they have settled on a surface, entering them through their skin.<ref>{{Cite journal|last1=Nussbaumer|first1=Andrea D.|last2=Fisher|first2=Charles R.|last3=Bright|first3=Monika|date=2006-05-18|title=Horizontal endosymbiont transmission in hydrothermal vent tubeworms|journal=Nature|volume=441|issue=7091|pages=345–348|doi=10.1038/nature04793|issn=1476-4687|pmid=16710420|bibcode=2006Natur.441..345N|s2cid=18356960}}</ref> This method of entry, known as horizontal transmission, means that each organism may have different species of bacteria assisting in this symbiosis. However, these bacteria all play similar roles in sustaining the vestimentiferans. Endosymbionts have a wide variety of metabolic genes, which may allow them to switch between autotrophic and heterotrophic methods of nutrient acquisition.<ref>{{Cite journal|last1=Reveillaud|first1=Julie|last2=Anderson|first2=Rika|last3=Reves-Sohn|first3=Sintra|last4=Cavanaugh|first4=Colleen|last5=Huber|first5=Julie A.|date=2018-01-27|title=Metagenomic investigation of vestimentiferan tubeworm endosymbionts from Mid-Cayman Rise reveals new insights into metabolism and diversity|journal=Microbiome|volume=6|issue=1|pages=19|doi=10.1186/s40168-018-0411-x|issn=2049-2618|pmc=5787263|pmid=29374496 |doi-access=free }}</ref> When the host dies, the bacteria are released and return to the free-living population in the seawater.<ref>{{Cite journal|last1=Klose|first1=Julia|last2=Polz|first2=Martin F.|last3=Wagner|first3=Michael|last4=Schimak|first4=Mario P.|last5=Gollner|first5=Sabine|last6=Bright|first6=Monika|date=2015-09-08|title=Endosymbionts escape dead hydrothermal vent tubeworms to enrich the free-living population|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=112|issue=36|pages=11300–11305|doi=10.1073/pnas.1501160112|issn=1091-6490|pmc=4568656|pmid=26283348|bibcode=2015PNAS..11211300K|doi-access=free}}</ref>

Discovery of the hydrothermal vents in the eastern Pacific Ocean was quickly followed by the discovery and description of new vestimentiferan tubeworm species. These tubeworms are one of the most dominant organisms associated with the hydrothermal vents in the Pacific Ocean. Tubeworms anchor themselves to the substratum of the [[Cold seep|hydrocarbon seep]] by roots located at the basal portion of their bodies.<ref>{{cite journal|doi=10.1007/s002270050233 |last1=Halanych |first1=K. |last2=Maas |first2=P. |last3=Hoeh |first3=W. |last4=Hashimoto |first4=J. |last5=Desbruyeres |first5=D. |last6=Lutz |first6=R. |last7=Vrijenhoek |first7=R. |title=Molecular systematics of vestimentiferan tubeworms from hydrothermal vents and cold-water seeps|year=1997|journal=Marine Biology|volume=130|issue=2|pages=141–149|s2cid=13217485 }}</ref> Intact tubeworm roots have proven very difficult to obtain for study because they are extremely delicate, and often break off when a tubeworm is removed from hypothermal vent regions. How long the roots of the tube worms can grow is unknown, but roots have been recovered longer than 30&nbsp;m.{{Citation needed|date=May 2023}}

A single aggregation of tubeworms can contain thousands of individuals, and the roots produced by each tubeworm can become tangled with the roots of neighbouring tubeworms.<ref>{{cite journal|pmid=10441078 |last1=Julian |first1=D. |last2=Gaill |first2=F. |last3=Wood |first3=E. |last4=Arp |first4=A. |last5=Fisher |first5=C. |title=Roots as a site of hydrogen sulphide uptake in the hydrocarbon seep vestimentiferan ''Lamellibrachia'' sp |url=http://jeb.biologists.org/content/202/17/2245.short |year=1999|volume=202|issue=Pt 17|pages=2245–57|journal=The Journal of Experimental Biology|doi=10.1242/jeb.202.17.2245 }}</ref> These mats of roots are known as "ropes", and travel down the tubes of dead tubeworms, and run through holes in rocks. The diameter and wall thickness of the tubeworm roots do not appear to change with distance from the trunk portion of the tubeworm's body.

Like the trunk portion of the body, the roots of the vestimentiferan tubeworms are composed of [[chitin]] crystallites, which support and protect the tubeworm from predation and environmental stresses. Tubeworms build the external chitin structure themselves by secreting chitin from specialized glands located in their body walls.