Abstract
The mud sediments of the eastern China marginal seas (ECMS) are deposited under different hydrodynamic conditions with different organic matter sources. These events have been demonstrated to exert significant influences on microbial communities and biogeochemical processes in surface sediments. However, the extent to which such effects occur in subsurface microbial communities remains unclear. In this study, both horizontal and vertical (five sites, each for eight layers) distributions of bacterial abundance and community composition in mud deposits of the South Yellow Sea (SYS) and East China Sea (ECS) were investigated by quantitative PCR and Illumina sequencing of the 16S rRNA gene. Both bacterial abundance and diversity were higher in the ECS than in the SYS, and tended to be higher in up than in deep layers. Proteobacteria (JTB255 marine benthic group), Acidobacteria and Bacteroidetes were dominant in the upper layers, whereas Lactococcus, Pseudomonas, and Dehalococcoidia were enriched in the deep layers. The bacterial communities in surface and subsurface sediments showed different inter-taxa relationships, indicating contrasting co-occurrence patterns. The bacterial communities in the upper layer samples clustered in accordance with mud zones, whereas those in the deep layer samples of all sites tended to cluster together. TOC δ13C and TON δ15N significantly affected the bacterial community composition, suggesting that the abundance and composition of organic matter played critical roles in shaping of sedimentary bacterial communities. This study provides novel insights into the distribution of subsurface bacterial communities in mud deposits of the ECMS, and provides clues for understanding the biogeochemical cycles in this area.
Highlights
Marginal seas are the transitional zones between the coastal and open oceans and occupy about 10% of the global ocean
Most studies mentioned above were based on surface sediments, but relatively few have focused on the vertical profile of bacterial communities in typical marginal sediments (Franco et al, 2007; Böer et al, 2009; Harrison et al, 2009; Liu et al, 2014)
At all sites, the NO3− concentration in pore water, Total organic carbon (TOC) and total nitrogen (TN) content in sediment had a tendency to decrease with depth
Summary
Marginal seas are the transitional zones between the coastal and open oceans and occupy about 10% of the global ocean These shallow, narrow and fast-deposition areas are reported to be major reservoirs of organic carbon burial in the marine system (Hedges and Keil, 1995), and have significant impacts on global biogeochemical cycles and even global climate changes to a Bacterial Communities in Marginal Sediments considerable degree (Chen C.T.A. et al, 2004; Coelho et al, 2013). Sediments in these areas harbor a higher abundance of microbes than those in open oceans (Kallmeyer et al, 2012). The extent to which the benthic surface environmental heterogeneity affect subsurface microbial communities needs further investigation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
