Comparative study of vent and seep macrofaunal communities in the Guaymas Basin

[摘要] Understanding the ecological processes and connectivity of chemosyntheticdeep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulfof California, Mexico), the presence of seeps and vents in the absence of abiogeographic barrier, and comparable sedimentary settings and depths offers aunique opportunity to assess the role of ecosystem-specific environmentalconditions on macrofaunal communities. Six seep and four vent assemblageswere studied, three of which were characterised by common major foundationtaxa: vesicomyid bivalves, siboglinid tubeworms and microbial mats.Macrofaunal community structure at the family level showed that density,diversity and composition patterns were primarily shaped by seep- and vent-common abiotic factors including methane and hydrogen sulfide concentrations, whereas vent environmental specificities (highertemperature, higher metal concentrations and lower pH) were not significant.The type of substratum and the heterogeneity provided by foundation specieswere identified as additional structuring factors and their roles were foundto vary according to fluid regimes. At the family level, seep and ventsimilarity reached at least 58 %. All vent families were found at seepsand each seep-specific family displayed low relative abundances (< 5 %). Moreover, 85 % of the identified species among dominant familieswere shared between seep and vent ecosystems. This study provides furthersupport to the hypothesis of continuity among deep-sea seep and ventecosystems.

[学科分类] 地球化学与岩石