Biogeography of the Sediment Bacterial Community Responds to a Nitrogen Pollution Gradient in the East China Sea

Abstract

Patterns of microbial distribution represent the integrated effects of historical and biological processes and are thus a central issue in ecology. However, there is still active debate on whether dispersal limitation contributes to microbial diversification in strongly connected systems. In this study, sediment samples were collected along a transect representing a variety of seawater pollution levels in the East China Sea. We investigated whether changes in sediment bacterial community structures would indicate the effects of the pollution gradient and of dispersal limitation. Our results showed consistent shifts in bacterial communities in response to pollution. More geographically distant sites had more dissimilar communities (r ‫؍‬ ؊0.886, P < 0.001) in this strongly connected sediment ecosystem. A variance analysis based on partitioning by principal coordinates of neighbor matrices (PCNM) showed that spatial distance (dispersal limitation) contributed more to bacterial community variation (8.2%) than any other factor, although the environmental factors explained more variance when combined (11.2%). In addition, potential indicator taxa (primarily affiliated with Deltaproteobacteria and Gammaproteobacteria) were identified; these taxa characterized the pollution gradient. This study provides direct evidence that dispersal limitation exists in a strongly connected marine sediment ecosystem and that candidate indicator taxa can be applied to evaluate coastal pollution levels.

Regional variations in the diversity and predicted metabolic potential of benthic prokaryotes in coastal northern Zhejiang, East China Sea

“…The dominant phyla and proteobacterial classes were similar to those previously reported in coastal sediments89. We observed that Cyanobacteria were not dominant in the sediments, with a low average relative abundance (0.011%, data not shown).…”

“…This could be partly explained by the limited light-permeability of the turbid waters containing a great amount of suspended particles in the study area overall27. Correspondingly, a number of previous works reported that Cyanobacteria were not dominant in the coastal marine sediments9115556. The LDA taxonomic cladogram indicated a biogeographic pattern of prokaryotic assemblages across zones at multiple taxonomic levels.…”

“…Benthic prokaryotes play crucial roles in biogeochemical cycling within marine ecosystems123. The diversity of benthic prokaryotes has been investigated across various coastal marine ecosystems456789, demonstrating a wide range of environmental drivers shaping benthic prokaryotic communities such as sediment depth10, water depth11, temperature12, ocean currents5, sediment texture8, salinity6, nutrients13, organic matter quantity and availability14, heavy metals and organic pollutants7. Previous studies have suggested that geographic distance also drives variation in benthic prokaryotic communities1516.…”

Response of Bacterioplankton Communities to Cadmium Exposure in Coastal Water Microcosms with High Temporal Variability

“…Overall, a gradual vanishing of phytoplankton biomass over time was observed, while there was a slight decrease in DO in the later stage of incubation (see Table S1 in the supplemental material). The importance of phytoplankton and DO in shaping the marine bacterioplankton community has been confirmed before (51)(52)(53), as were other driving factors here (7,16,24). Phosphate and Cd share a similar direction in shaping the bacterial community (Fig.…”

“…Current knowledge on how and to what extent the coastal bacterioplankton community responds to the competition and interaction between toxic metals and temporal succession is scarce. In addition, it is unclear whether bacterial assemblages with robust temporal variability can be applied to reflect Cd pollution in seawater, although several recent studies have found significant correlations between the bacterial community and specific environment changes such as spatial and seasonal gradients, nitrogen pollution, and outbreak of shrimp disease (19,24,25).…”