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

Abstract

Abstract. Understanding the ecological processes and connectivity of chemosynthetic deep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulf of California, Mexico), the presence of seeps and vents in the absence of a biogeographic barrier, and comparable sedimentary settings and depths offers a unique opportunity to assess the role of ecosystem-specific environmental conditions on macrofaunal communities. Six seep and four vent assemblages were studied, three of which were characterised by common major foundation taxa: 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 (higher temperature, higher metal concentrations and lower pH) were not significant. The type of substratum and the heterogeneity provided by foundation species were identified as additional structuring factors and their roles were found to vary according to fluid regimes. At the family level, seep and vent similarity reached at least 58 %. All vent families were found at seeps and each seepspecific family displayed low relative abundances (< 5 %). Moreover, 85 % of the identified species among dominant families were shared between seep and vent ecosystems. This study provides further support to the hypothesis of continuity among deep-sea seep and vent ecosystems.

Comparative Study of Guaymas Basin Microbiomes: Cold Seeps vs. Hydrothermal Vents Sediments

“…Based on genomecentric metagenomic, members of these taxa have been proposed as potential degraders of organic matters in marine sediments, degrading aromatic compounds (Wasmund et al, 2016), scavenging dead cells (Lloyd et al, 2013;Robbins et al, 2016;Lazar et al, 2017) or fermenting various carbohydrates (Nobu et al, 2016). These heterotrophic microbial communities identified in both cold seep and hydrothermal sediments might be supported by the high sedimentary rates and the important microbial and meiofaunal biomass (Portail et al, 2015) likely generating the important organic carbon concentrations measured in the Guaymas Basin seafloor (Lin et al, 2017). Thus, these potential organic matter degraders might represent an important proportion of the "core microbiome" of the Guaymas Basin chemosynthetic areas.…”

Picturing thermal niches and biomass of hydrothermal vent species

“…Colaço et al, 2002;De Busserolles et al, 2009;Portail et al, 2015). Fewer studies have simultaneously estimated the biomass and the link between density distributions and food-web structure (Bergquist et al, 2007).…”

Macrofaunal Ecology of Sedimented Hydrothermal Vents in the Bransfield Strait, Antarctica

“…In the Southern Ocean, where benthos are relatively sensitive to temperature fluctuations (Barnes and Peck, 2008;Clarke et al, 2009), it is likely that the relatively hot conditions presented by SHVs represented a significant deterrent to background fauna. However, in Guaymas basin macrofaunal assemblages, concentrations of sulfide and methane were found to be drivers of compositional differences and temperature was not a significant factor (Portail et al, 2015). In the absence of temperature data, chlorinity profiles were used.…”