Dataset Information

Diversity and predictive metabolic pathways of the prokaryotic microbial community along a groundwater salinity gradient of the Pearl River Delta, China.

ABSTRACT: Almost half of the groundwater in the Pearl River Delta (PRD) contains salt water originally derived from paleo-seawater due to the Holocene transgression, which then generates intense physicochemical gradients in the mixing zone between freshwater and saltwater. Although some studies have been conducted on the hydrological and geochemical characteristics of groundwater in the PRD to monitor the intrusion of seawater, little attention has been paid to the microbial community of this particular region. In this study, we implemented a high-throughput sequencing analysis to characterize the microbial communities along a salinity gradient in the PRD aquifer, China. Our results indicated that the microbial community composition varied significantly depending on the salinity of the aquifer. The presence of abundant anaerobic microorganisms of the genera Desulfovibrio and Methanococcus in certain saltwater samples may be responsible for the gas generation of H2S and CH4 in the stratum. In saline water samples (TDS?>?10?g/L), the linear discriminant analysis effect size (LEfSe) analysis found two biomarkers that usually live in marine environments, and the aquifers of the PRD still contained large quantity of saltwater, indicating that the impact of the paleo-seawater has lasted to this day. The predictive metagenomic analysis revealed that the metabolic pathways present in the groundwater samples studied, included the degradation of pesticides and refractory organics (dichlorodiphenyltrichloroethane (DDT), atrazine and polycyclic aromatic hydrocarbons), matter cycling (methane, nitrogen and sulfur), and inorganic ion and mineral metabolites. This study can help enhance our understanding of the composition of the microbial assemblages and its implications as an environmental indicator in an aquifer affected by saltwater intrusion.

SUBMITTER: Sang S

PROVIDER: S-EPMC6251883 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature

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Diversity and predictive metabolic pathways of the prokaryotic microbial community along a groundwater salinity gradient of the Pearl River Delta, China.

Sang Shilei S Zhang Xiaoying X Dai Heng H Hu Bill X BX Ou Hao H Sun Liwei L

Scientific reports 20181123 1

Almost half of the groundwater in the Pearl River Delta (PRD) contains salt water originally derived from paleo-seawater due to the Holocene transgression, which then generates intense physicochemical gradients in the mixing zone between freshwater and saltwater. Although some studies have been conducted on the hydrological and geochemical characteristics of groundwater in the PRD to monitor the intrusion of seawater, little attention has been paid to the microbial community of this particular r ...[more]

PMID: 30470770

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Project description:Microbial communities mediate the biogeochemical cycles that drive ecosystems, and it is important to understand how these communities are affected by changing environmental conditions, especially in complex coastal zones. As fresh and marine waters mix in estuaries and river plumes, the salinity, temperature, and nutrient gradients that are generated strongly influence bacterioplankton community structure, yet, a parallel change in functional diversity has not been described. Metagenomic and metatranscriptomic analyses were conducted on five water samples spanning the salinity gradient of the Columbia River coastal margin, including river, estuary, plume, and ocean, in August 2010. Samples were pre-filtered through 3 μm filters and collected on 0.2 μm filters, thus results were focused on changes among free-living microbial communities. Results from metagenomic 16S rRNA sequences showed taxonomically distinct bacterial communities in river, estuary, and coastal ocean. Despite the strong salinity gradient observed over sampling locations (0 to 33), the functional gene profiles in the metagenomes were very similar from river to ocean with an average similarity of 82%. The metatranscriptomes, however, had an average similarity of 31%. Although differences were few among the metagenomes, we observed a change from river to ocean in the abundance of genes encoding for catabolic pathways, osmoregulators, and metal transporters. Additionally, genes specifying both bacterial oxygenic and anoxygenic photosynthesis were abundant and expressed in the estuary and plume. Denitrification genes were found throughout the Columbia River coastal margin, and most highly expressed in the estuary. Across a river to ocean gradient, the free-living microbial community followed three different patterns of diversity: 1) the taxonomy of the community changed strongly with salinity, 2) metabolic potential was highly similar across samples, with few differences in functional gene abundance from river to ocean, and 3) gene expression was highly variable and generally was independent of changes in salinity.

Dataset Information

Diversity and predictive metabolic pathways of the prokaryotic microbial community along a groundwater salinity gradient of the Pearl River Delta, China.

Publications

Diversity and predictive metabolic pathways of the prokaryotic microbial community along a groundwater salinity gradient of the Pearl River Delta, China.

Similar Datasets

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