Biogeography and Biodiversity in Sulfide Structures of Active and Inactive Vents at Deep-Sea Hydrothermal Fields of the Southern Mariana Trough

Abstract

The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive vents were investigated by culture-independent methods. These sulfide structures were collected at four hydrothermal fields, both on-and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the Epsilonproteobacteria and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active vents. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive vents. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of hydrothermal activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive vents are likely to be comparable to or higher than those in active vent structures, even though the microbial community composition is different between these two types of vents. The microbial community compositions in the sulfide structures of inactive vents were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active vents, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and microbial ecosystems in marine environments.

Intra-Field Variation of Prokaryotic Communities On and Below the Seafloor in the Back-Arc Hydrothermal System of the Southern Mariana Trough

“…22), as their energy sources, even if the supply of hydrothermal fluids ceases. The difference between active and inactive chimney samples may reflect the temporal change before and after the cease of hydrothermal activity, i.e., temperature, pH and Eh, in addition to availability of Table 24.1 for the sample description reduced chemical species (Kato et al 2010), which is consistent with the previous study of 9 N EPR (Sylvan et al 2012).…”

“…The 16S rRNA gene sequences were recovered from ironrich mats (YS16 and YS18) (Kato et al 2009a), active (AFhm, APcsc, APbsc, AAcs) and inactive chimneys (IPltc, IYdc, Inoc) (Kato et al 2010;Kato et al Chap. 9), crustal fluids obtained from boreholes (Fapm1a, Fapm1b, Papm3, F2apm1), a natural vent fluid (Fnv) and ambient seawater (Pasw and Fasw) (Kato et al 2009b) in the SMT hydrothermal fields, i.e., Snail, Pika, Archaean, Kaiko and Yamanaka sites (Suppl.…”

“…1). Numerous studies have characterized the prokaryotic community structures in various habitat types, such as hydrothermally active chimneys (e.g., Flores et al 2012a;Kato et al 2010;Kormas et al 2006;Nakagawa et al 2005;Schrenk et al 2003;Takai and Horikoshi 1999), inactive chimneys (Kato et al 2010;Suzuki et al 2004;Sylvan et al 2012), iron-rich mats (e.g., Davis and Moyer 2008;Fleming et al 2013;Forget et al 2010;Kato et al 2009a), and crustal fluids (Cowen et al 2003;Huber et al 2006;Kato et al 2009bKato et al , 2013Orcutt et al 2011), in various deep-sea hydrothermal fields. Through such studies, interfield variation between prokaryotic community structures in deep-sea hydrothermal system habitats has been revealed (e.g., Takai et al 2006;Flores et al 2012a).…”

Microbial Biodiversity and Biogeography on the Deep Seafloor

“…Furthermore, recently, massive sulfide deposits and Mn crusts on the deep seafloor have been focused on as mineral www.intechopen.com resources (Rona, 2003;Hoagland et al, 2010). There are diverse microbes on/in these seafloor minerals (Kato et al, 2010;Nitahara et al, 2011). Microbial biogeography on the deep seafloor will contribute ultimately to develop deep-sea mining techniques utilizing microbes in future.…”

“…To assess how the environmental similarity (i.e., contemporary physicochemical condition) and geographic distance (i.e., historical event) affect on the distribution patterns of biodiversity of microbial communities or population, -diversity are associated with physicochemical and geographic differences among each environment. A variety of habitats in natural environments have been targeted for microbial biogeography, such as soil (Cho & Tiedje, 2000;Fierer & Jackson, 2006), lake sediments (Yannarell & Triplett, 2005), ocean (García-Martínez & Rodríguez-Valera, 2000), deep-sea sediments (Schauer et al, 2009) and deep-sea hydrothermal fields (Kato et al, 2010). These studies have suggested that the distribution pattern of microbes in habitats is controlled by not only environmental factors (e.g., pH, salinity and oxygen concentration) but also geographic isolation.…”