Different Responses of Bacterial and Archaeal Communities in River Sediments to Water Diversion and Seasonal Changes

Abstract

In recent years, different responses of archaea and bacteria to environmental changes have attracted increasing scientific interest. In the mid-latitude region, Fen River receives water transferred from the Yellow River, electrical conductivity (EC), concentrations of Cl^- and Na⁺ in water, total phosphorus (TP), and Olsen phosphorus (OP) in sediments were significantly affected by water transfer. Meanwhile, temperature and oxidation-reduction potential (ORP) of water showed significant seasonal variations. Based on 16S rRNA high-throughput sequencing technology, the composition of bacteria and archaea in sediments was determined in winter and summer, respectively. Results showed that the dominance of bacterial core flora decreased and that of archaeal core flora increased after water diversion. The abundance and diversity of bacterial communities in river sediments were more sensitive to anthropogenic and naturally induced environmental changes than that of archaeal communities. Bacterial communities showed greater resistance than archaeal communities under long-term external disturbances, such as seasonal changes, because of rich species composition and complex community structure. Archaea were more stable than bacteria, especially under short-term drastic environmental disturbances, such as water transfer, due to their insensitivity to environmental changes. These results have important implications for understanding the responses of bacterial and archaeal communities to environmental changes in river ecosystems affected by water diversion.

Keywords: 16SrRNA high-throughput sequencing; archaea; bacteria; river sediments; seasonal changes; water transfer.

Figure 1

Map of the study area and sampling sites.

Figure 2

Result of the principal component analysis of physicochemical parameters of river water and sediments. Here, 95% confidence ellipses of sampling groups are shown. The sequencing results of the sampling points FR01–FR06 in winter and summer were labeled as W1–W6 and S1–S6, respectively.

Figure 3

The microbial composition of bacteria (a) and archaea (b). The smallest taxonomic unit is the genus. The relevant abundance of taxa less than 1% were classified as others. The sequencing results of the sampling points FR01–FR06 in winter and summer were labeled as W1–W6 and S1–S6, respectively.

Figure 4

Heat map of environmental factor correlations of bacteria. The significant level was symbolled as: *: p ≤ 0.05, **: p ≤ 0.01, ***: p ≤ 0.001. Red represented positive correlation, blue represented negative correlation, the darker the color, the greater the correlation. The range of positive and negative correlation coefficients is −1 to 1. TP: total phosphorus; T: temperature; SOM: soil organic matter; EC: electrical conductivity; TDS: total dissolved solid; AN: alkaline nitrogen; ORP: oxidation-reduction potential; PS: particle size; TN: total nitrogen; OP: Olsen phosphorus; TK: total potassium; AK: alkaline potassium.

Figure 5

Heat map of environmental factor correlations of archaea. The significant level was symbolled as: *: p ≤ 0.05, **: p ≤ 0.01, ***: p ≤ 0.001. Red represented positive correlation, blue represented negative correlation, the darker the color, the greater the correlation. The range of positive and negative correlation coefficients is −1 to 1. TP: total phosphorus; T: temperature; SOM: soil organic matter; EC: electrical conductivity; TDS: total dissolved solid; AN: alkaline nitrogen; ORP: oxidation-reduction potential; PS: particle size; TN: total nitrogen; OP: Olsen phosphorus; TK: total potassium; AK: alkaline potassium.

Figure 6

Significance test for bacterial (a) and archaeal (b) differences due to seasonal variation. The significant level was symbolled as *: p ≤ 0.05, **: p ≤ 0.01.

Figure 7

Significance test for bacterial (a) and archaeal (b) differences due to water diversion. The significant level was symbolled as *: p ≤ 0.05, **: p ≤ 0.01.

Figure 8

Hierarchical clustering of bacteria (a) and archaea (b). The length of the scale represents the differences between the community composition structures of the samples. The longer the distance is, the greater the difference becomes. The sequencing results of the sampling points FR01–FR06 in winter and summer were labeled as W1–W6 and S1–S6, respectively.

Figure 9

Network analysis of bacteria (a) and archaea (b). Nodes represent taxa, and the size of the node indicates the relative abundance of the taxon. Different colors of nodes represent different phylum. The red line represents a positive correlation between the two bacteria and the green line represents a negative correlation.