The specific hypotheses to be addressed by our outlined approach may be summarized as follows: (1) The presence of extensive numbers of mussels within selected regions of the vent faunal assemblage inhibits the colonization and subsequent growth of vestimentiferan tubeworms
through depletion of [H.sub.2]S below critical levels; (2) If mussels were to be removed and subsequently excluded from regions with elevated temperatures and [H.sub.2]S concentrations within a mussel population at an active vent site along the East Pacific Rise, then the area will be colonized by numerous vent-endemic species, including Tevnia jerichonana and Riftia pachyptila, which reportedly represent "early vent colonizers"; see Shank et al.
Symbiosis involving chemoautotrophic bacteria allows vestimentiferan tubeworms
to thrive in sulfidic marine environments.
There, the rugged and strangely beautiful seafloor landscape is carpeted with crabs, snails, and tubeworms
living around tall hydrothermal vent chimneys, some the size of six-story buildings.
Many of the unusual life-forms spotted there- clams, tubeworms
, mussels, and crabs, for example-also reside at ocean seeps, sites where methane, oil, and other fluids ooze out of the sediment and into the surrounding water (SN: 9/27/86, p.
In areas where venting is more diffuse (<30 [degrees]C, [H.sub.2]S concentrations roughly 0.20-0.30 mmol [kg.sup.-1], moderately acidic pH; Le Bris et al., 2006), vestimentiferan tubeworms
, sometimes mixed with mussels, predominate.
His dashed hopes were partially allayed when, nearby, researchers found tiny tubeworms
, thumb-sized mussels, and other new life that probably arose in the aftermath of the eruption that destroyed Rose Garden.
By December, the structures had been colonized by encrusting bryozoans, decorator crab (Oregonia gracilis), RKC, calcareous tubeworms
, and nudibranchs (Flabellina fusca).
In a stunning case of serendipity, oceanographers conducting a submarine survey have discovered a scene of underwater carnage--a site in the Pacific Ocean where recent lava eruptions sizzled a community of tubeworms
and other animals living on the ocean floor.
Slides at the time of sampling typically displayed an early successional marine community comprising a biofilm of bacteria and algae, as well as a rich assembly of epifauna, including juvenile sponges, foraminiferans, tubeworms
, hydrozoans, copepods, snails, bryozoans, and ascidians.
The off-spring of tubeworms
, giant clams, and other organisms that form thriving communities of life around seafloor hydrothermal vents must find the right conditions for them to settle down, live, grow, and reproduce.
In some places, tubeworms
have already established residency.
Levels of interspecific COI divergence found between species of deep-sea bivalve molluscs, siboglinid tubeworms
, and decapod crustaceans typically exceed 4%, whereas intraspecific divergence is less than 2% (Peek et al., 1997; Shank et al., 1998; Guinot et al., 2002; Hurtado et al., 2002, 2004; Goffredi et al., 2003; Won et al., 2003; Rouse et al., 2004).