Variation in community structure within hydrothermal vent mussel beds of the East Pacific Rise

Abstract

Patterns in invertebrate community structure associated with mussel beds at 3 hydrothermal vents on the northern East Pacific Rise (NEPR) were explored using quantitative, replicate sampling methods and were compared to those of southern East Pacific Rise (SEPR) mussel beds (~3000 km apart). Univariate measures of diversity (H ', J ') did not differ among 3 NEPR mussel beds. Diversity by most estimates was lower at NEPR mussel beds than at SEPR mussel beds. Invertebrate faunas of NEPR and SEPR mussel beds belong to the same biogeographic province, and the numerically dominant species at NEPR mussel beds were also numerical dominants at SEPR mussel beds. Patterns of community structure within and among NEPR mussel beds, between NEPR and SEPR mussel beds, and between 'young' (< 6 yr) and 'old' (> 8 yr) mussel beds could be differentiated using multivariate techniques based on species-abundance matrices. Overall, these observations suggest that NEPR and SEPR mussel-bed communities are remarkably similar, differing primarily in the relative abundances of their shared, numerically dominant species and in the composition of the rare species.KEY WORDS: Community structure · Hydrothermal vent · East Pacific Rise · Mussel beds · Diversity Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 253: [55][56][57][58][59][60][61][62][63][64][65][66] 2003 seeps have the potential to provide critical counterpoints to those observed in non-chemosynthetically based deep-sea communities.Two attributes of deep-sea hydrothermal systemstheir insularity and their gradient regimes of fluid flow and chemistry -suggested a priori that measures of community structure and similarity at vents would be especially sensitive to the degree of proximity between sites being compared, to the age of the sites and to within-site heterogeneity. These factors, however, might be counterbalanced by the transiency of hydrothermal vents, which places a premium on effective dispersal and recruitment. Hydrothermal vents on mid-ocean ridges are fragmented systems that occur as small islands of habitat along a narrow corridor of hard substratum; invertebrates colonizing these habitats have larval stages that are subject to dispersal in an open system, although mechanisms of larval retention must exist to account for the large settlement events observed (Mullineaux & France 1995, Marsh et al. 2001, Van Dover et al. 2001. Vent habitats, especially those of fast-spreading centers such as the East Pacific Rise (EPR), where there is a rich magma budget and extensive volcanism, undergo a relatively rapid hydrothermal cycle of waxing and waning (on the order of days to decades; Haymon et al. 1993, Delaney et al. 1998, Shank et al. 1998. At the start of a hydrothermal cycle, when new loci of diffuse flow are formed, the habitat is rich in the sulfide on which chemoauotrophic microorganisms depend. For the more stable sites, diffuse flow lasts for years, followed inevitably and ultimately by reduction in flow and ...

A biological survey method applied to seafloor massive sulphides (SMS) with contagiously distributed hydrothermal-vent fauna

“…Site differences for vent assemblages situated just a few kilometers apart are now well documented and have been correlated with factors such as the age of the biogenic habitat that de fines the assemblage (e.g. Van Dover 2003, Dreyer et al 2005. Multi variate analyses indicated that peripheral vent fauna of Solwara 1 and South Su samples were well differentiated from the active vent assemblages (presence− absence data).…”

Diversity of meiofauna and free-living nematodes in hydrothermal vent mussel beds on the northern and southern East Pacific Rise

“…This technique risks possible loss of macrofaunal individuals through winnowing compared with the closed bag technique of the pot samplers. Consequently, scoop samples have previously been included in analyses of macrofaunal species richness but excluded from multivariate analyses of macrofaunal composition (Van Dover & Trask, 2000;Van Dover, 2002;Dorries & Van Dover, 2003;Turnipseed et al, 2003;Van Dover, 2003;Dreyer et al, 2005). The abundance of nematodes per litre of mussel volume, however, is actually greater in scoop samples than pot samples, indicating that this meiofaunal taxon is resistant to any winnowing effect.…”

“…The macrofaunal assemblages of young (<6 y) and old (>8 y) mussel beds could also be distinguished by multivariate analysis (Van Dover, 2003;Dreyer et al, 2005).…”

Development of macrofaunal community structure in mussel beds on the northern East Pacific Rise

“…The prevailing view, however, is that vent communities are unstable, varying dramatically in composition and structure over time, with especially rapid transitions during the commencement and cessation of fluid flow (e.g. Tunnicliffe et al 1997, Shank et al 1998, Mullineaux et al 2000, 2003, Tsurumi & Tunnicliffe 2001. The least stable vent communities reported to date may be those associated with large sulfide edifices in vent fields on the Juan de Fuca ABSTRACT: Comparisons of macrofaunal community structure (species composition, abundance, biovolume, rank order, species richness, diversity) in hydrothermal vent mussel beds at 9°50' N (9N) on the East Pacific Rise were made from analysis of multiple quantitative samples collected in 1999 and 2001 from each of 3 mussel beds of known age (4 to 8 yr in 1999).…”