Environmental Filtering by pH and Salinity Jointly Drives Prokaryotic Community Assembly in Coastal Wetland Sediments

Abstract

Understanding the microbial community assembly is an essential topic in microbial ecology. Coastal wetlands are an important blue carbon sink, where microbes play a key role in biogeochemical cycling of nutrients and energy transformation. However, the drivers controlling the distribution patterns and assembly of bacterial and archaeal communities in coastal wetland are unclear. Here we examined the diversity, co-occurrence network, assembly processes and environmental drivers of bacterial and archaeal communities from inshore to offshore sediments by the sequencing of 16S rRNA gene amplicons. The value of α- and β-diversity of bacterial and archaeal communities generally did not change significantly (P > 0.05) between offshore sites, but changed significantly (P < 0.05) among inshore sites. Sediment pH and salinity showed significant effects on the diversity and keystone taxa of bacterial and archaeal communities. The bacterial and archaeal co-occurrence networks were inextricably linked with pH and salinity to formed the large network nodes, suggesting that they were the key factors to drive the prokaryotic community. We also identified that heterogeneous and homogeneous selection drove the bacterial and archaeal community assembly, while the two selections became weaker from offshore sites to inshore sites, suggesting that deterministic processes were more important in offshore sites. Overall, these results suggested that the environmental filtering of pH and salinity jointly governed the assembly of prokaryotic community in offshore sediments. This study advances our understanding of microbial community assembly in coastal wetland ecosystems.

Fungi and cercozoa regulate methane-associated prokaryotes in wetland methane emissions

“…In addition, Module V was correlated significantly with pH. In previous studies, pH is one of the key factors driving the prokaryotic community in offshore sediments (Yu et al, 2022). This environmental factor mainly affects the prokaryotic community through affecting the structure of microbial cell membrane and availability of soil nutrients (Gabler et al, 2017;Wang et al, 2020).…”

Chemoautotrophic sulphur oxidizers dominate microbial necromass carbon formation in coastal blue carbon ecosystems

“…Meanwhile, S oxidizers were found to be the core root microbiome of saltmarsh and seagrass, and showed a direct correlation with plant species (Crump et al, 2018;Rolando et al, 2022) Plants could recruit specific soil microbiomes, and the effect of plant species on microbiomes is driven by differences in plant characteristics, plant genetics and root exudates (Wagner et al, 2016;Zancarini et al, 2021;Zhalnina et al, 2018). Several studies have reported that coastal ecosystems vegetated with different plant species showed significant differences in sediment microbiomes (Liu et al, 2020(Liu et al, , 2023Muwawa et al, 2021;Wang et al, 2020;Yu et al, 2022;Yu, Yang, et al, 2020). For example, the bacterial community composition was influenced by mangrove species and sediment chemical properties (Muwawa et al, 2021), and chemical properties such as pH, salinity, TC and TN could be impacted by the plant species (He et al, 2018;Zhou et al, 2016).…”

“…A total of 30 samples (5 sites, 6 replicates) were collected, and then transported to the laboratory in a portable cooler at 4°C within 24 h. Each sample was divided into two subsamples: one was stored at 4°C for physical and chemical analysis, and the other was kept at −80°C for microbial community DNA extraction. More details of the sampling sites are described in a previous study (Yu et al, 2022).…”

“…For example, the introduced mangrove S. apetala was found to have higher fine root turnover rates but lower C sequestration compared to their native counterparts (He et al, 2021). Although coastal sediments vegetated by native or alien species harboured distinct microbial communities (Yu et al, 2022; Yu, Yang, et al, 2020), few reports have explored how microorganisms influence the sediment C sequestration in these ecosystems. Therefore, it is necessary to understand the contribution of microbially mediated C, N and S cycling, especially for C fixation to C sequestration in coastal ecosystems.…”

Uniform selective pressures within redox zones drive gradual changes in microbial community composition in hadal sediments

“…Null model-based approaches use randomizations to measure if, and how much, dissimilarities between two communities deviate from the random (null) expectation, allowing the relative importance of neutral and deterministic processes to be estimated (Chase et al, 2011;Stegen et al, 2013). These null-modelling metrics were previously applied to 16S rRNA gene amplicon data from marine sediments (Liu et al, 2022;Yu et al, 2022) and lend qualitative support to the hypothesis that selection strongly influences microbial community assembly (Petro et al, 2017). Still, community assembly processes in marine sediments are highly complex and our understanding of how selection actually manifests in the community structures observed in these systems remains sparse.…”